- Email: [email protected]
Managing Incidentalomas Safely: Do Computed Tomography Requisitions Tell Us What We Need to Know?
Canadian Association of Radiologists Journal 68 (2017) 387e391 www.carjonline.org
Computed Tomography / Tomodensitometrie
Managing Incidentalomas Safely: Do Computed Tomography Requisitions Tell Us What We Need to Know? Matthew Walker, MD, Joy Borgaonkar, MD, FRCPC, Daria Manos, MD, FRCPC* Department of Diagnostic Radiology, Dalhousie University, Halifax, Nova Scotia, Canada
Abstract Purpose: Technological advancements and the ever-increasing use of computed tomography (CT) have greatly increased the detection of incidental findings, including tiny pulmonary nodules. The management of many ‘‘incidentalomas’’ is significantly influenced by a patient’s history of cancer. The study aim is to determine if CT requisitions include prior history of malignancy. Methods: Requisitions for chest CTs performed at our adult tertiary care hospital during April 2012 were compared to a cancer history questionnaire, administered to patients at the time of CT scan. Patients were excluded from the study if the patient questionnaire was incomplete or if the purpose of the CT was for cancer staging or cancer follow-up. Results: A total of 569 CTs of the chest were performed. Of the 327 patients that met inclusion criteria, 79 reported a history of cancer. After excluding patients for whom a history of malignancy could not be confirmed through a chart review and excluding nonmelanoma skin cancer, dysplasia, and in situ neoplasm, 68 patients were identified as having a history of malignancy. We found 44% (95% confidence interval [0.32-0.57]) of the chest CT requisitions for these 68 patients did not include the patient’s history of cancer. Of the malignancies that were identified by patient questionnaire but omitted from the clinical history provided on the requisitions, 47% were malignancies that commonly metastasize to the lung. Conclusions: A significant number of requisitions failed to disclose a history of cancer. Without knowledge of prior malignancy, radiologists cannot comply with current guidelines regarding the reporting and management of incidental findings. Resume Objectif : Les progres technologiques et l’utilisation toujours plus repandue de la tomodensitometrie (TDM) ont permis d’ameliorer grandement la detection des constatations fortuites, y compris de minuscules nodules pulmonaires. La gestion de nombreux « fortuitomes » depend largement des antecedents de cancer du patient. L’etude vise a determiner si les demandes de TDM comprennent les antecedents de malignite. Methodes : Les demandes correspondant aux TDM thoraciques effectuees a notre h^ opital de soins tertiaires aux adultes en avril 2012 ont ete comparees a un questionnaire sur les antecedents de cancer soumis aux patients au moment de l’examen de TDM. Les patients dont le questionnaire etait incomplet ou dont la TDM visait la stadification ou le suivi d’un cancer ont ete exclus. Resultats : Un total de 569 TDM thoraciques ont ete effectuees. Sur les 327 patients qui correspondaient aux criteres d’inclusion, 79 avaient des antecedents de cancer. Apres avoir exclu les patients pour lesquels il a ete impossible de confirmer les antecedents de malignite par un examen du dossier ainsi que ceux qui souffraient de cancers de la peau autre qu’un melanome, de dysplasie et d’une tumeur in situ, 68 patients ont ete definis comme ayant des antecedents de malignite. Nous avons decouvert que 44 % (intervalle de confiance de 95 % [de 0,32 a 0,57]) des demandes de TDM thoracique pour ces 68 patients ne comprenaient pas leurs antecedents de cancer. Sur les malignites declarees dans les questionnaires des patients, mais omises dans les antecedents cliniques fournis avec les demandes, 47 % etaient des malignites qui metastasent couramment au poumon. Conclusions : Un nombre important de demandes n’indiquaient pas les antecedents de cancer. S’ils ne connaissent pas les malignites anterieures, les radiologistes ne peuvent pas se conformer aux lignes directrices sur la declaration et la gestion des constatations fortuites. Ó 2016 Canadian Association of Radiologists. All rights reserved. Key Words: Guidelines; Incidental; Medical error; Pulmonary nodules; Reporting; Requisitions
* Address for correspondence: Daria Manos, MD, FRCPC, Department of Diagnostic Radiology, Dalhousie University, Victoria Building, 1276 South Park Street, PO BOX 9000, Halifax, Nova Scotia B3H 2Y9, Canada.
E-mail address: [email protected] (D. Manos).
0846-5371/$ - see front matter Ó 2016 Canadian Association of Radiologists. All rights reserved. http://dx.doi.org/10.1016/j.carj.2016.11.004
388
M. Walker et al. / Canadian Association of Radiologists Journal 68 (2017) 387e391
Diagnostic imaging requisitions with insufficient, inaccurate, or illegible clinical information is a long-standing and well-documented concern [1e3]. Several studies have shown that incomplete or absent clinical history reduces sensitivity for detecting disease and that accurate focused clinical information on requisitions does not deteriorate specificity [4e6]. The impact on medical error is clear; radiologists are better able to detect and interpret imaging findings when aware of the clinical context. But how do requisitions affect reporting of asymptomatic imaging findings? Do radiologists have enough past medical history information to safely interpret asymptomatic incidental findings? In 2012 an estimated 4.4 million computed tomography (CT) scans were performed in Canada (126 per 1000 people), nearly double the number of such exams performed in 2003 [7]. The growth of CT coupled with continuous improvements in image quality and spatial resolution has resulted in a marked increase in incidental detection of asymptomatic abnormalities. For example, large studies of CT colongraphy have revealed incidental extracolonic findings in 41%-69% of exams [8,9]. Incidental pulmonary nodules present a particular challenge. Up to 60% of adults will have at least 1 noncalcified pulmonary nodule detectable on chest CT [10e12]. Although lung nodules are a common benign finding, they are also a common manifestation of metastatic disease. In asymptomatic smokers and former smokers there is a malignant rate of less than 1% for patients with pulmonary nodules measuring 4 mm or less (Figure 1) [13e15]. However, similar-sized pulmonary nodules discovered in patients with pre-existing extrapulmonary cancers have been shown to have a malignant rate of 28% (Figure 2) [16]. Unfortunately tiny benign lung nodules may appear identical to early metastatic disease. Under the Mayo Clinic model the most important factor in determining the pretest probability of malignancy in small pulmonary nodules is a history of extrathoracic cancer, which independently produces an odds ratio of 3.8 [17]. The effect of prior malignancy on the significance of incidental findings is not limited to lung nodules. The American College of Radiology published a white paper on incidental abdominal CT findings to provide guidance to radiologists and to help curb unnecessary work-up. The initial step in the algorithm regarding many incidental lesions of uncertain etiology, including adrenal lesions, depends on whether the patient is known to have a malignancy [18]. Given the increased identification of incidentalomas and the critical role of prior cancer history in determining the significance of these lesions, it is important that radiologists are aware of prior cancer history when reporting CTs. The objective of this study is to determine the percentage of chest CT requisitions that have not included a patient’s previous history of cancer. Methods We reviewed requisitions for CTs of the chest performed at our adult tertiary care hospital during the period April 1-30,
Figure 1. Incidental nodule requiring no surveillance. Axial computed tomography (CT) of the lung demonstrates a 3-mm nodule (arrow) in a 56-year-old woman without a history of cancer. This is a benign nodule. Follow-up CT (not shown) was performed 1 year later for another reason and demonstrated no growth in the nodule.
2012. The month of April was selected as a convenience sample. CTs of the chest were identified by electronic search of the picture archiving and communication system (PACS) using variables ‘‘study description includes chest’’ and ‘‘modality equals CT.’’ The resultant electronic work list with cases identified by accession number served as the study group. Cases in the study group were reviewed directly on PACS. At our institution CTs are ordered through a paper requisition. This requisition is then scanned into PACS. We compared the CT requisition completed by the referring physician to information obtained directly from the patient by the CT technologist. Information from the patient was obtained as part of a routine demographic risk profiling tool used clinically in our Diagnostic Radiology Department. Technologists administer a short questionnaire immediately before every CT of the chest. The questionnaire responses are then scanned and appended to the patient’s electronic radiology chart. One of the questions the patients are asked is whether they have ever had cancer. If the patient reports a history of cancer, the patient is then asked to identify the type of cancer. Requisitions were excluded if the associated patient questionnaire had not been completed or if the requisition was illegible. Additionally, patients for whom the imaging was being conducted for the purpose of cancer staging were excluded from the study because any pulmonary nodules detected by these scans would not be incidental findings. All other CTs of the chest were included in the study. Review of the electronic medical chart was performed for all patients who identified a history of cancer on the questionnaire but presented with requisitions that did not include this history. Pathology reports, discharge summaries, and clinic notes were used to verify the history supplied by the patient. Benign neoplasms (eg, uterine leiomyoma), dysplasia, and in situ neoplasm (eg, in the cervix) were not considered cancers for the purposes of this
Incomplete requisitions / Canadian Association of Radiologists Journal 68 (2017) 387e391
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Figure 2. Incidental nodule requiring surveillance. (A) Axial computed tomography (CT) of the lung reveals an unexpected 3-mm nodule (arrow) in a 73-yearold man with a history of bladder cancer. Because of the history of prior malignancy, follow-up CT is indicated. (B) Serial CTs demonstrated progressive growth best demonstrated on an axial CT 1 year later. Core biopsy was consistent with urothelial metastases.
study. All skin malignancies except melanoma were excluded. Institutional ethics board approval was obtained for this study. A proportion with associated 95% confidence interval was computed using a 1-sample proportions test with continuity correction, where the event of interest was the omission of cancer history in a referring physician’s requisition. Results A total of 569 chest CTs were performed during the month of April 2012; 242 (43%) were excluded from analysis due to the following reasons: in 87 of the cases the patient was not able to complete the questionnaire (eg, unresponsive or intubated patient) and the remaining 155 were excluded because the purpose of the CT was for cancer staging. None of the requisitions were excluded for being illegible. Of the 327 requisitions included in analysis, 79 related to patients who self-reported a history of malignancy. Chart review could not confirm prior malignant tumour for 6 patients (including 2 out-of-province patients with unavailable charts). Chart review also excluded 5 patients whose cancer history was of nonmelanoma skin cancer. For the remaining 68 patients with a verified history of malignancy, 30 (44%; 95% confidence interval [0.32-0.57]) had that history excluded from the requisition. Because several patients had a history of more than 1 type of cancer, in total 34 cancers were excluded from the CT requisitions. The types of malignancy identified by the patients and the ordering physicians are summarized in Table 1. Discussion The fact that close to 50% of patients with a history of cancer had that aspect of their clinical history omitted from their requisition is worrying. Lack of clinical information on requisitions is not a new observation [2,3,19]. However, the marked increase in the detection of incidental findings in conjunction with incomplete requisitions presents a recently more prevalent safety concern.
Knowledge regarding a patient’s history of malignancy affects the way a radiologist reports incidental findings including the significance and follow up recommendations. For example, in accordance with the referral guidelines adopted by the Canadian Association of Radiologists, a 60-year-old nonsmoker with a 3-mm pulmonary nodule requires no further follow-up. If that same patient has a history of breast cancer, further investigation is required to evaluate for the possibility of metastatic disease [20]. For lung nodules under 5 mm, radiologists may even omit these findings in a report for a patient for whom no history of malignancy is included on the CT requisition [21e23]. We have observed that radiologists sometimes attempt to compensate for the lack of history by providing 2 distinct recommendations, 1 for a patient at high risk for a malignant nodule and 1 for a patient at low risk. In these situations we note that some referring physicians prefer to follow the high-risk recommendations even for patients who do not meet high-risk criteria. This results in inappropriate radiation exposure and use of medical resources.
Table 1 Prior history of cancer in patients undergoing a nonstaging computed tomography of the chest
Cancer type Breast Colorectal and gastric Lung Prostate Bladder and renal Cervical, uterine, ovarian Melanoma Hematologic Head and neck Other (adrenal, thyroid, sarcoma, pancreatic) Total
Excluded from requisition
Included on requisition
Total
5 6 1 4 6 1 5 2 1 3
9 8 12 6 0 2 0 2 3 2
14 14 13 10 6 5 5 4 4 5
34
46
80
Total numbers are calculated for numbers of cancers, not numbers of patients. Four patients had a history of 2 or more cancers.
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There may be many reasons why a history of cancer is omitted from the clinical information supplied on CT requisitions. One possible explanation is that referring physicians may believe that certain types of cancers are less material to the evaluation of pulmonary lesions. The physicians who excluded the cancer history for 4 patients with prostate cancer might have done so appropriately. Conversely cancer history was included on the requisition for 12 of the 13 patients with prior lung malignancy. This may be an indication that referring physicians are only including cancer histories that they feel are relevant to an evaluation of the thorax. However, a significant number of cancers that commonly metastasize to the lungs were also omitted from the requisitions. Among autopsy cases, breast, colon, kidney, uterus, and head and neck cancers are the most common causes of pulmonary metastasis [24,25]. In our study, patients with a history of 1 or more of these cancers accounted for 47% of the cancers omitted from requisitions. Physicians may not be considering the possibility of incidental findings when they are completing a CT requisition. Referring physicians may also not be aware of the substantial overlap in imaging appearance between benign findings and early malignant disease. Although our study is limited by a small sample size, the confidence interval suggests the results are valid. We were unable to accurately determine if there is a pattern regarding which types of cancers are more likely to be omitted from CT requisitions. The study was also too small to determine if physicians are predominantly excluding remote malignancies or excluding cancer history predominantly in older patients. Additionally, our ability to independently verify prior cancer history was limited by use of an electronic medical file that excluded most information prior to 2004 and did not routinely include information on health visits out of province. This meant we had to exclude 6 patients who reported a history of cancer that we could not verify. We also likely excluded some cancers in poorly informed or demented patients. Indeed, in 2 cases, the referring physician made note of a history of cancer that the patient did not disclose. In both cases the patients were in their 80s. Conclusion Our study explores another source of poor communication between requesting physicians and radiologists. Radiologists cannot assume prior cancer history is included on CT imaging requests. Physician education programs, structured physician order entry forms and computerized order entry systems have been shown to improve the quality of supplied clinical information [26e28]. Expanding these programs to emphasize the importance of prior malignancy may help ensure radiologists have enough information to use new guidelines regarding incidental findings. This may have important safety and medicolegal effects. At our institution direct communication with the patient has helped obtain the additional clinical history required to more accurately report CTs.
Acknowledgements This project received funding from the Dalhousie Radiology Research Foundation. The authors wish to thank Dr Candice Crocker for her help with manuscript preparation.
References [1] Munk P. The Holy Grail - the quest for reliable radiology requisition histories. Can Assoc Radiol J 2016;67:1. [2] Obara P, Sevenster M, Travis A, et al. Evaluating the referring physician’s clinical history and indication as a means for communicating chronic conditions chat are pertinent at the point of radiologic interpretation. J Digit Imaging 2015;28:272e82. [3] Rhea JT, Potsaid MS, DeLuca SA. Errors of interpretation as elicited by a quality audit of an emergency radiology facility. Radiology 1979; 132:277e80. [4] Loy CT, Irwig L. Accuracy of diagnostic tests read with and without clinical information; a systematic review. JAMA 2004;292:1602e9. [5] Mullins MS, Lev MH, Schellingerhout D, Koroshetz WJ, Gonzalez RG. Influence of availability of clinical history of detection of early stroke using unenhanced CT and diffusion-weighted MR imaging. AJR Am J Roentgenol 2002;179:223e8. [6] Doubilet P, Herman PG. Interpretation of radiographs: effect of clinical history. AJR Am J Roentgenol 1981;137:1055e8. [7] Medical Imaging in Canada. Canadian Institute for Health Information: 2013. Available at: cihi.ca/CIHI-ext-portal/pdf/internet/MIT_SUMMARY_ 2012_en. Accessed May 25, 2016. [8] Gluecker TM, Johnson CD, Wilson LA, et al. Extracolonic findings at CT colonography: evaluation of prevalence and cost in a screening population. Gastroenterology 2003;124:911e6. [9] Halligan S, Wooldrage K, Dadswell E. Identification of extracolonic pathologies by computed tomographic colonography in symptomatic patients. Gastroenterology 2015;149:89e101. [10] van Klaveren RJ, Oudkerk M, Prokop M, et al. Management of lung nodules detected by volume CT scanning. N Engl J Med 2009;361: 2221e9. [11] Swensen SJ, Jett JR, Hartman TE, et al. Lung cancer screening with CT: Mayo Clinic experience. Radiology 2003;226:756e61. [12] Gohagan J, Marcus P, Fagerstrom R, et al. Baseline findings of a randomized feasibility trial of lung cancer screening with spiral CT scan vs chest radiograph: the Lung Screening Study of the National Cancer Institute. Chest 2004;126:114e21. [13] Swensen SJ, Jett JR, Hartman TE, et al. CT screening for lung cancer: five-year prospective experience. Radiology 2005;235:259e65. [14] McWilliams AM, Mayo JR, Ahn MI, MacDonald SL, Lam SC. Lung cancer screening using multi-slice thin-section computed tomography and autofluorescence bronchoscopy. J Thorac Oncol 2006;1:61e8. [15] McWilliams A, Tammemagi M, Mayo J, et al. Probability of cancer in pulmonary nodules detected on first screening CT. N Engl J Med 2013; 369:910e9. [16] Munden RF, Erasmus JJ, Wahba H, Fineberg NS. Follow-up of small (4mm or less) incidentally detected nodules by computed tomography in oncology patients: a retrospective review. J Thorac Oncol 2010;5: 1958e62. [17] Swensen SJ, Silverstein MD, Ilstrup DM, Schleck CD, Edell ES. The probability of malignancy in solitary pulmonary nodules. Application to small radiologically indeterminate nodules. Arch Intern Med 1997; 157:849e55. [18] Berland LL, Silverman SG, Gore RM, et al. Managing incidental findings on abdominal CT: white paper of the ACR incidental findings committee. J Am Coll Radiol 2010;7:754e73. [19] Gunderman RB, Phillips MD, Cohen MD. Improving clinical histories on radiology requisitions. Acad Radiol 2001;8:299e303.
Incomplete requisitions / Canadian Association of Radiologists Journal 68 (2017) 387e391 [20] 2012 CAR Diagnostic Imaging Referral Guidelines, Section F - Thoracic. Ottawa, Canada: Canadian Association of Radiologists; 2012. Available at: http://car.ca/en/standards-guidelines/guidelines.aspx. Accessed September 9, 2013. [21] Herold C. Ignore it or explore it; how to manage incidentally detected pulmonary nodules (abstract). Cancer Imaging 2007;(suppl). [22] Jeudy J, White CS, Munden RF, Boiselle PM. Management of small (3e5-mm) pulmonary nodules at chest CT: global survey of thoracic radiologists. Radiology 2008;247:847e53. [23] Eisenberg RL, Bankier AA, Boiselle PM. Compliance with Fleischner Society guidelines for management of small lung nodules: a survey of 834 radiologists. Radiology 2010;255:218e24.
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[24] Crow J, Slavin G, Kreel L. Pulmonary metastases: a pathologic and radiologic study. Cancer 1981;47:2595e602. [25] Coppage L, Shaw C, Curtis AM. Metastatic disease to the chest in patients with extrathoracic malignancy. J Thorac Imaging 1987;2:24e37. [26] Wortman JR, Goud A, Raja AS, Marchello D, Sodickson A. Structured physician order entry for trauma CT: value in improving clinical information transfer and billing efficiency. AJR Am J Roentgenol 2014;203:1242e8. [27] Alkasab TK, Alkasab JR, Abujudeh HH. Effects of a computerized provider order entry system on clinical histories provided in emergency department radiology requisitions. J Am Coll Radiol 2009;6:194e200. [28] Troude P, Dozol A, Soyer P, et al. Improvement of radiology requisition. Diagn Interv Imaging 2014;95:69e75.
Computed Tomography / Tomodensitometrie
Managing Incidentalomas Safely: Do Computed Tomography Requisitions Tell Us What We Need to Know? Matthew Walker, MD, Joy Borgaonkar, MD, FRCPC, Daria Manos, MD, FRCPC* Department of Diagnostic Radiology, Dalhousie University, Halifax, Nova Scotia, Canada
Abstract Purpose: Technological advancements and the ever-increasing use of computed tomography (CT) have greatly increased the detection of incidental findings, including tiny pulmonary nodules. The management of many ‘‘incidentalomas’’ is significantly influenced by a patient’s history of cancer. The study aim is to determine if CT requisitions include prior history of malignancy. Methods: Requisitions for chest CTs performed at our adult tertiary care hospital during April 2012 were compared to a cancer history questionnaire, administered to patients at the time of CT scan. Patients were excluded from the study if the patient questionnaire was incomplete or if the purpose of the CT was for cancer staging or cancer follow-up. Results: A total of 569 CTs of the chest were performed. Of the 327 patients that met inclusion criteria, 79 reported a history of cancer. After excluding patients for whom a history of malignancy could not be confirmed through a chart review and excluding nonmelanoma skin cancer, dysplasia, and in situ neoplasm, 68 patients were identified as having a history of malignancy. We found 44% (95% confidence interval [0.32-0.57]) of the chest CT requisitions for these 68 patients did not include the patient’s history of cancer. Of the malignancies that were identified by patient questionnaire but omitted from the clinical history provided on the requisitions, 47% were malignancies that commonly metastasize to the lung. Conclusions: A significant number of requisitions failed to disclose a history of cancer. Without knowledge of prior malignancy, radiologists cannot comply with current guidelines regarding the reporting and management of incidental findings. Resume Objectif : Les progres technologiques et l’utilisation toujours plus repandue de la tomodensitometrie (TDM) ont permis d’ameliorer grandement la detection des constatations fortuites, y compris de minuscules nodules pulmonaires. La gestion de nombreux « fortuitomes » depend largement des antecedents de cancer du patient. L’etude vise a determiner si les demandes de TDM comprennent les antecedents de malignite. Methodes : Les demandes correspondant aux TDM thoraciques effectuees a notre h^ opital de soins tertiaires aux adultes en avril 2012 ont ete comparees a un questionnaire sur les antecedents de cancer soumis aux patients au moment de l’examen de TDM. Les patients dont le questionnaire etait incomplet ou dont la TDM visait la stadification ou le suivi d’un cancer ont ete exclus. Resultats : Un total de 569 TDM thoraciques ont ete effectuees. Sur les 327 patients qui correspondaient aux criteres d’inclusion, 79 avaient des antecedents de cancer. Apres avoir exclu les patients pour lesquels il a ete impossible de confirmer les antecedents de malignite par un examen du dossier ainsi que ceux qui souffraient de cancers de la peau autre qu’un melanome, de dysplasie et d’une tumeur in situ, 68 patients ont ete definis comme ayant des antecedents de malignite. Nous avons decouvert que 44 % (intervalle de confiance de 95 % [de 0,32 a 0,57]) des demandes de TDM thoracique pour ces 68 patients ne comprenaient pas leurs antecedents de cancer. Sur les malignites declarees dans les questionnaires des patients, mais omises dans les antecedents cliniques fournis avec les demandes, 47 % etaient des malignites qui metastasent couramment au poumon. Conclusions : Un nombre important de demandes n’indiquaient pas les antecedents de cancer. S’ils ne connaissent pas les malignites anterieures, les radiologistes ne peuvent pas se conformer aux lignes directrices sur la declaration et la gestion des constatations fortuites. Ó 2016 Canadian Association of Radiologists. All rights reserved. Key Words: Guidelines; Incidental; Medical error; Pulmonary nodules; Reporting; Requisitions
* Address for correspondence: Daria Manos, MD, FRCPC, Department of Diagnostic Radiology, Dalhousie University, Victoria Building, 1276 South Park Street, PO BOX 9000, Halifax, Nova Scotia B3H 2Y9, Canada.
E-mail address: [email protected] (D. Manos).
0846-5371/$ - see front matter Ó 2016 Canadian Association of Radiologists. All rights reserved. http://dx.doi.org/10.1016/j.carj.2016.11.004
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Diagnostic imaging requisitions with insufficient, inaccurate, or illegible clinical information is a long-standing and well-documented concern [1e3]. Several studies have shown that incomplete or absent clinical history reduces sensitivity for detecting disease and that accurate focused clinical information on requisitions does not deteriorate specificity [4e6]. The impact on medical error is clear; radiologists are better able to detect and interpret imaging findings when aware of the clinical context. But how do requisitions affect reporting of asymptomatic imaging findings? Do radiologists have enough past medical history information to safely interpret asymptomatic incidental findings? In 2012 an estimated 4.4 million computed tomography (CT) scans were performed in Canada (126 per 1000 people), nearly double the number of such exams performed in 2003 [7]. The growth of CT coupled with continuous improvements in image quality and spatial resolution has resulted in a marked increase in incidental detection of asymptomatic abnormalities. For example, large studies of CT colongraphy have revealed incidental extracolonic findings in 41%-69% of exams [8,9]. Incidental pulmonary nodules present a particular challenge. Up to 60% of adults will have at least 1 noncalcified pulmonary nodule detectable on chest CT [10e12]. Although lung nodules are a common benign finding, they are also a common manifestation of metastatic disease. In asymptomatic smokers and former smokers there is a malignant rate of less than 1% for patients with pulmonary nodules measuring 4 mm or less (Figure 1) [13e15]. However, similar-sized pulmonary nodules discovered in patients with pre-existing extrapulmonary cancers have been shown to have a malignant rate of 28% (Figure 2) [16]. Unfortunately tiny benign lung nodules may appear identical to early metastatic disease. Under the Mayo Clinic model the most important factor in determining the pretest probability of malignancy in small pulmonary nodules is a history of extrathoracic cancer, which independently produces an odds ratio of 3.8 [17]. The effect of prior malignancy on the significance of incidental findings is not limited to lung nodules. The American College of Radiology published a white paper on incidental abdominal CT findings to provide guidance to radiologists and to help curb unnecessary work-up. The initial step in the algorithm regarding many incidental lesions of uncertain etiology, including adrenal lesions, depends on whether the patient is known to have a malignancy [18]. Given the increased identification of incidentalomas and the critical role of prior cancer history in determining the significance of these lesions, it is important that radiologists are aware of prior cancer history when reporting CTs. The objective of this study is to determine the percentage of chest CT requisitions that have not included a patient’s previous history of cancer. Methods We reviewed requisitions for CTs of the chest performed at our adult tertiary care hospital during the period April 1-30,
Figure 1. Incidental nodule requiring no surveillance. Axial computed tomography (CT) of the lung demonstrates a 3-mm nodule (arrow) in a 56-year-old woman without a history of cancer. This is a benign nodule. Follow-up CT (not shown) was performed 1 year later for another reason and demonstrated no growth in the nodule.
2012. The month of April was selected as a convenience sample. CTs of the chest were identified by electronic search of the picture archiving and communication system (PACS) using variables ‘‘study description includes chest’’ and ‘‘modality equals CT.’’ The resultant electronic work list with cases identified by accession number served as the study group. Cases in the study group were reviewed directly on PACS. At our institution CTs are ordered through a paper requisition. This requisition is then scanned into PACS. We compared the CT requisition completed by the referring physician to information obtained directly from the patient by the CT technologist. Information from the patient was obtained as part of a routine demographic risk profiling tool used clinically in our Diagnostic Radiology Department. Technologists administer a short questionnaire immediately before every CT of the chest. The questionnaire responses are then scanned and appended to the patient’s electronic radiology chart. One of the questions the patients are asked is whether they have ever had cancer. If the patient reports a history of cancer, the patient is then asked to identify the type of cancer. Requisitions were excluded if the associated patient questionnaire had not been completed or if the requisition was illegible. Additionally, patients for whom the imaging was being conducted for the purpose of cancer staging were excluded from the study because any pulmonary nodules detected by these scans would not be incidental findings. All other CTs of the chest were included in the study. Review of the electronic medical chart was performed for all patients who identified a history of cancer on the questionnaire but presented with requisitions that did not include this history. Pathology reports, discharge summaries, and clinic notes were used to verify the history supplied by the patient. Benign neoplasms (eg, uterine leiomyoma), dysplasia, and in situ neoplasm (eg, in the cervix) were not considered cancers for the purposes of this
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Figure 2. Incidental nodule requiring surveillance. (A) Axial computed tomography (CT) of the lung reveals an unexpected 3-mm nodule (arrow) in a 73-yearold man with a history of bladder cancer. Because of the history of prior malignancy, follow-up CT is indicated. (B) Serial CTs demonstrated progressive growth best demonstrated on an axial CT 1 year later. Core biopsy was consistent with urothelial metastases.
study. All skin malignancies except melanoma were excluded. Institutional ethics board approval was obtained for this study. A proportion with associated 95% confidence interval was computed using a 1-sample proportions test with continuity correction, where the event of interest was the omission of cancer history in a referring physician’s requisition. Results A total of 569 chest CTs were performed during the month of April 2012; 242 (43%) were excluded from analysis due to the following reasons: in 87 of the cases the patient was not able to complete the questionnaire (eg, unresponsive or intubated patient) and the remaining 155 were excluded because the purpose of the CT was for cancer staging. None of the requisitions were excluded for being illegible. Of the 327 requisitions included in analysis, 79 related to patients who self-reported a history of malignancy. Chart review could not confirm prior malignant tumour for 6 patients (including 2 out-of-province patients with unavailable charts). Chart review also excluded 5 patients whose cancer history was of nonmelanoma skin cancer. For the remaining 68 patients with a verified history of malignancy, 30 (44%; 95% confidence interval [0.32-0.57]) had that history excluded from the requisition. Because several patients had a history of more than 1 type of cancer, in total 34 cancers were excluded from the CT requisitions. The types of malignancy identified by the patients and the ordering physicians are summarized in Table 1. Discussion The fact that close to 50% of patients with a history of cancer had that aspect of their clinical history omitted from their requisition is worrying. Lack of clinical information on requisitions is not a new observation [2,3,19]. However, the marked increase in the detection of incidental findings in conjunction with incomplete requisitions presents a recently more prevalent safety concern.
Knowledge regarding a patient’s history of malignancy affects the way a radiologist reports incidental findings including the significance and follow up recommendations. For example, in accordance with the referral guidelines adopted by the Canadian Association of Radiologists, a 60-year-old nonsmoker with a 3-mm pulmonary nodule requires no further follow-up. If that same patient has a history of breast cancer, further investigation is required to evaluate for the possibility of metastatic disease [20]. For lung nodules under 5 mm, radiologists may even omit these findings in a report for a patient for whom no history of malignancy is included on the CT requisition [21e23]. We have observed that radiologists sometimes attempt to compensate for the lack of history by providing 2 distinct recommendations, 1 for a patient at high risk for a malignant nodule and 1 for a patient at low risk. In these situations we note that some referring physicians prefer to follow the high-risk recommendations even for patients who do not meet high-risk criteria. This results in inappropriate radiation exposure and use of medical resources.
Table 1 Prior history of cancer in patients undergoing a nonstaging computed tomography of the chest
Cancer type Breast Colorectal and gastric Lung Prostate Bladder and renal Cervical, uterine, ovarian Melanoma Hematologic Head and neck Other (adrenal, thyroid, sarcoma, pancreatic) Total
Excluded from requisition
Included on requisition
Total
5 6 1 4 6 1 5 2 1 3
9 8 12 6 0 2 0 2 3 2
14 14 13 10 6 5 5 4 4 5
34
46
80
Total numbers are calculated for numbers of cancers, not numbers of patients. Four patients had a history of 2 or more cancers.
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There may be many reasons why a history of cancer is omitted from the clinical information supplied on CT requisitions. One possible explanation is that referring physicians may believe that certain types of cancers are less material to the evaluation of pulmonary lesions. The physicians who excluded the cancer history for 4 patients with prostate cancer might have done so appropriately. Conversely cancer history was included on the requisition for 12 of the 13 patients with prior lung malignancy. This may be an indication that referring physicians are only including cancer histories that they feel are relevant to an evaluation of the thorax. However, a significant number of cancers that commonly metastasize to the lungs were also omitted from the requisitions. Among autopsy cases, breast, colon, kidney, uterus, and head and neck cancers are the most common causes of pulmonary metastasis [24,25]. In our study, patients with a history of 1 or more of these cancers accounted for 47% of the cancers omitted from requisitions. Physicians may not be considering the possibility of incidental findings when they are completing a CT requisition. Referring physicians may also not be aware of the substantial overlap in imaging appearance between benign findings and early malignant disease. Although our study is limited by a small sample size, the confidence interval suggests the results are valid. We were unable to accurately determine if there is a pattern regarding which types of cancers are more likely to be omitted from CT requisitions. The study was also too small to determine if physicians are predominantly excluding remote malignancies or excluding cancer history predominantly in older patients. Additionally, our ability to independently verify prior cancer history was limited by use of an electronic medical file that excluded most information prior to 2004 and did not routinely include information on health visits out of province. This meant we had to exclude 6 patients who reported a history of cancer that we could not verify. We also likely excluded some cancers in poorly informed or demented patients. Indeed, in 2 cases, the referring physician made note of a history of cancer that the patient did not disclose. In both cases the patients were in their 80s. Conclusion Our study explores another source of poor communication between requesting physicians and radiologists. Radiologists cannot assume prior cancer history is included on CT imaging requests. Physician education programs, structured physician order entry forms and computerized order entry systems have been shown to improve the quality of supplied clinical information [26e28]. Expanding these programs to emphasize the importance of prior malignancy may help ensure radiologists have enough information to use new guidelines regarding incidental findings. This may have important safety and medicolegal effects. At our institution direct communication with the patient has helped obtain the additional clinical history required to more accurately report CTs.
Acknowledgements This project received funding from the Dalhousie Radiology Research Foundation. The authors wish to thank Dr Candice Crocker for her help with manuscript preparation.
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