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Evaluation of Diffusion-Weighted MRI to Differentiate Atelectasis From Lung Cancer in Radiation Therapy Planning
S26
International Journal of Radiation Oncology Biology Physics
Systems. M. Simoff: E. Research Grant; Varian Medical Systems. C.H. Stone: None. K.A. Jenrow: None. K. Lapanowski: None. M. Ajlouni: None. I.J. Chetty: E. Research Grant; Varian Medical Systems. A. Movsas: None. M. Lu: None. A. Sitarik: None. L. Lamerato: None. M.R. Jones: None. Z. Hammoud: None. N. Peshkin: None. K. Roszka: None. R. Parry: A. Employee; Varian Medical Systems.
malignant pleural mesothelioma (MPM). MPM is known to recur in prior chest wall biopsy, incision, and scar sites. While prophylactic irradiation of tracts (PIT) can potentially decrease surgical tract chest wall recurrences after biopsies and extrapleural pneumonectomies, no definitive data exist assessing PIT after RP. We hypothesized that PIT can be safely delivered as an adjuvant to RP, and that patients with en bloc resection and low risk, early stage disease can forgo PIT without increased tract recurrence rates. Materials/Methods: Seventy-nine consecutive patients treated on 1 of 2 IRB-approved prospective trials between 10/2005 and 4/2013 with RP and intraoperative photodynamic therapy (PDT) were evaluated. Adjuvant radiation therapy to tract sites was only administered if patients exhibited “high risk features” prior to or during resection, including gross residual disease, multistation mediastinal nodal metastases, T4 disease with aortic invasion, diffuse extension of tumor in the chest wall, or tumor seeding along a prior incision site noted and excised during RP. Results: Adjuvant radiation therapy was administered to 11 patients (14%) for residual disease (nZ2), nodal metastasis (nZ3), aortic invasion (nZ1), and/or PIT for extensive chest wall invasion (nZ6) or prior tract seeding (nZ1). Of the 11 patients receiving adjuvant radiation therapy, at a median follow-up of 23.4 months from surgery, no tract site recurrences occurred. No grade >2 acute or late toxicity was observed in any patient receiving radiation therapy. At a median follow-up of 14.3 months from surgery and 23.6 months among living patients, of the 68 patients not receiving adjuvant radiation therapy, only 4 (6%) recurred in their chest wall tract sites at a median of 10.6 months after RP (range 0.7-69.0 months). Receiving adjuvant radiation therapy did not significantly impact rates of tract site control (100% vs 94%, PZ.42). Adjuvant radiation therapy also did not impact rates of locoregional or distant control or overall survival (all P>.05). Conclusions: This study demonstrates excellent durable control of tract sites following RP in patients with high risk features receiving adjuvant radiation therapy. PIT was well tolerated and should be considered in this patient population. This study found low rates of tract site recurrence without adjuvant radiation therapy in lower risk patients undergoing oncologic en bloc resection and PDT. PIT may be safely avoided in this patient population. Tract site recurrence rates and the safety and benefit of PIT following RP alone or RP with alternative intraoperative adjuvants like intrapleural chemotherapy or povidone-iodine should be assessed. Author Disclosure: A.R. Barsky: None. J.P. Buckley: None. J.S. Friedberg: None. M. Culligan: None. S.M. Hahn: None. K.A. Cengel: None. C.B. Simone: None.
150 Evaluation of Diffusion-Weighted MRI to Differentiate Atelectasis From Lung Cancer in Radiation Therapy Planning Locally Advanced Non-Small Cell Lung Cancer S. Saraiya,1 G. Hugo,1 K. Karki,1 K. Olsen,2 R. Groves,2 J. Ford,1 and E. Weiss1; 1Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, 2Department of Radiology, Virginia Commonwealth University, Richmond, VA Purpose/Objective(s): Differentiating atelectasis from active neoplasm in lung cancer has been shown to improve radiation therapy targeting. Currently, PET is the gold standard functional imaging technique for this purpose. We evaluated the ability of diffusion-weighted MRI (DW-MRI) to differentiate atelectasis from active tumor and compared it to PET/CTbased delineation for radiation therapy planning. Materials/Methods: In this pilot study, six patients with locally advanced non-small cell lung cancer underwent DW-MRI and PET/CT prior to chemoradiation therapy. Respiratory navigated DW-MRIs were acquired on a 1.5T scanner in axial planes with eight b-values ranging from 0-1000 s/mm2. Apparent diffusion coefficient (ADC) maps were derived using all b-value DW-MRI images. Primary tumor (PT) and atelectasis (A) were contoured on ADC maps and PET/CT images. Contours were drawn in consensus by 2 radiation oncologists using commercially available treatment planning software. For each patient, the mean ADC (ADCmean), max standard uptake values (SUVmax), and mean standard uptake values (SUVmean) were measured both for PT and A. The averages of all the parameters were calculated. Differences between PT and A were calculated for both functional imaging modalities. Paired t test was used to evaluate difference of ADCmean, SUVmax and SUVmean values between PT and A. While SUVmax is used in clinical practice, SUVmean was also used in the analysis for better comparability with mean ADC values. Results: The mean standard deviation of ADCmean over the subject population for primary tumor and atelectasis are 1269193 mm2/s (range: 996-1490 mm2/s ) and 1836236 mm2/s (range: 1513-2100 mm2/s), respectively. The mean SUVmax for primary tumor and atelectasis are 27.912.7 (range: 18.0- 52.5) and 8.85.0 (range: 4.2-18.0), respectively. The mean SUVmean for primary tumor and atelectasis are 10.52.4 (range: 7.9-14.3) and 2.52.1(range: 1.3-6.7), respectively. Using paired t test, the difference between ADCmean values of PT and A is highly significant (PZ.0014). For SUVmax and SUVmean, the differences between PT and A are significant as well (PZ.019 and PZ.0017, respectively). Conclusions: Results of this pilot study demonstrate that both DW-MRI and PET/CT show significant differences between PT and A. DW MRI provides relevant functional imaging information for radiation therapy planning that needs to be investigated further. Author Disclosure: S. Saraiya: None. G. Hugo: None. K. Karki: None. K. Olsen: None. R. Groves: None. J. Ford: None. E. Weiss: E. Research Grant; NIH, Varian and Phillips Medical Systems. P. Royalty; UpToDate.
151 Prophylactic Irradiation of Surgical Tract Sites in the Era of Radical Pleurectomy for Malignant Pleural Mesothelioma Mesothelioma, Thymic Malignancies, and Other Thoracic Malignancies A.R. Barsky, J.P. Buckley, J.S. Friedberg, M. Culligan, S.M. Hahn, K.A. Cengel, and C.B. Simone; University of Pennsylvania, Philadelphia, PA Purpose/Objective(s): Radical pleurectomy (RP) is increasingly performed and has emerged as a standard definitive surgical treatment for resectable
152 The Important Prognostic Value of Pretreatment Stage in Patients Achieving Pathologic Complete Response After Neoadjuvant Therapy of Esophageal Cancer Mesothelioma, Thymic Malignancies, and Other Thoracic Malignancies J. Yang,1 Z. Xiao,1 L. Tan,1 Z. Zhou,1 Q. Feng,1 L. Wang,1 H. Zhang,1 D. Chen,1 J. Liang,1 Z. Hui,1 W. Yin,1 and J. He2; 1Department of Radiation Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences (CAMS), Peking Union Medical College (PUMC), Beijing, China, 2Department of Thoracic Surgical Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences (CAMS), Peking Union Medical College (PUMC), Beijing, China Purpose/Objective(s): To evaluate the relation between pretreatment stage and pathologic response as well as prognosis after neoadjuvant radiation therapy in esophageal squamous cell cancer (ESCC). Materials/Methods: A total of 296 ESCC patients treated by neoadjuvant radiation therapy in our center between 1980 and 2007 were retrospectively reviewed. The prescription doses were 36w50 Gy (median, 40 Gy), 2 Gy each daily, 5 fractions per week. Radiation therapy was delivered with anteroposterior opposing fields for most patients. Radiation treatment area encompassed primary tumor and relevant lymph node regions. All patients received esophagectomy and 2-field lymphadenectomy 4 weeks after
International Journal of Radiation Oncology Biology Physics
Systems. M. Simoff: E. Research Grant; Varian Medical Systems. C.H. Stone: None. K.A. Jenrow: None. K. Lapanowski: None. M. Ajlouni: None. I.J. Chetty: E. Research Grant; Varian Medical Systems. A. Movsas: None. M. Lu: None. A. Sitarik: None. L. Lamerato: None. M.R. Jones: None. Z. Hammoud: None. N. Peshkin: None. K. Roszka: None. R. Parry: A. Employee; Varian Medical Systems.
malignant pleural mesothelioma (MPM). MPM is known to recur in prior chest wall biopsy, incision, and scar sites. While prophylactic irradiation of tracts (PIT) can potentially decrease surgical tract chest wall recurrences after biopsies and extrapleural pneumonectomies, no definitive data exist assessing PIT after RP. We hypothesized that PIT can be safely delivered as an adjuvant to RP, and that patients with en bloc resection and low risk, early stage disease can forgo PIT without increased tract recurrence rates. Materials/Methods: Seventy-nine consecutive patients treated on 1 of 2 IRB-approved prospective trials between 10/2005 and 4/2013 with RP and intraoperative photodynamic therapy (PDT) were evaluated. Adjuvant radiation therapy to tract sites was only administered if patients exhibited “high risk features” prior to or during resection, including gross residual disease, multistation mediastinal nodal metastases, T4 disease with aortic invasion, diffuse extension of tumor in the chest wall, or tumor seeding along a prior incision site noted and excised during RP. Results: Adjuvant radiation therapy was administered to 11 patients (14%) for residual disease (nZ2), nodal metastasis (nZ3), aortic invasion (nZ1), and/or PIT for extensive chest wall invasion (nZ6) or prior tract seeding (nZ1). Of the 11 patients receiving adjuvant radiation therapy, at a median follow-up of 23.4 months from surgery, no tract site recurrences occurred. No grade >2 acute or late toxicity was observed in any patient receiving radiation therapy. At a median follow-up of 14.3 months from surgery and 23.6 months among living patients, of the 68 patients not receiving adjuvant radiation therapy, only 4 (6%) recurred in their chest wall tract sites at a median of 10.6 months after RP (range 0.7-69.0 months). Receiving adjuvant radiation therapy did not significantly impact rates of tract site control (100% vs 94%, PZ.42). Adjuvant radiation therapy also did not impact rates of locoregional or distant control or overall survival (all P>.05). Conclusions: This study demonstrates excellent durable control of tract sites following RP in patients with high risk features receiving adjuvant radiation therapy. PIT was well tolerated and should be considered in this patient population. This study found low rates of tract site recurrence without adjuvant radiation therapy in lower risk patients undergoing oncologic en bloc resection and PDT. PIT may be safely avoided in this patient population. Tract site recurrence rates and the safety and benefit of PIT following RP alone or RP with alternative intraoperative adjuvants like intrapleural chemotherapy or povidone-iodine should be assessed. Author Disclosure: A.R. Barsky: None. J.P. Buckley: None. J.S. Friedberg: None. M. Culligan: None. S.M. Hahn: None. K.A. Cengel: None. C.B. Simone: None.
150 Evaluation of Diffusion-Weighted MRI to Differentiate Atelectasis From Lung Cancer in Radiation Therapy Planning Locally Advanced Non-Small Cell Lung Cancer S. Saraiya,1 G. Hugo,1 K. Karki,1 K. Olsen,2 R. Groves,2 J. Ford,1 and E. Weiss1; 1Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, 2Department of Radiology, Virginia Commonwealth University, Richmond, VA Purpose/Objective(s): Differentiating atelectasis from active neoplasm in lung cancer has been shown to improve radiation therapy targeting. Currently, PET is the gold standard functional imaging technique for this purpose. We evaluated the ability of diffusion-weighted MRI (DW-MRI) to differentiate atelectasis from active tumor and compared it to PET/CTbased delineation for radiation therapy planning. Materials/Methods: In this pilot study, six patients with locally advanced non-small cell lung cancer underwent DW-MRI and PET/CT prior to chemoradiation therapy. Respiratory navigated DW-MRIs were acquired on a 1.5T scanner in axial planes with eight b-values ranging from 0-1000 s/mm2. Apparent diffusion coefficient (ADC) maps were derived using all b-value DW-MRI images. Primary tumor (PT) and atelectasis (A) were contoured on ADC maps and PET/CT images. Contours were drawn in consensus by 2 radiation oncologists using commercially available treatment planning software. For each patient, the mean ADC (ADCmean), max standard uptake values (SUVmax), and mean standard uptake values (SUVmean) were measured both for PT and A. The averages of all the parameters were calculated. Differences between PT and A were calculated for both functional imaging modalities. Paired t test was used to evaluate difference of ADCmean, SUVmax and SUVmean values between PT and A. While SUVmax is used in clinical practice, SUVmean was also used in the analysis for better comparability with mean ADC values. Results: The mean standard deviation of ADCmean over the subject population for primary tumor and atelectasis are 1269193 mm2/s (range: 996-1490 mm2/s ) and 1836236 mm2/s (range: 1513-2100 mm2/s), respectively. The mean SUVmax for primary tumor and atelectasis are 27.912.7 (range: 18.0- 52.5) and 8.85.0 (range: 4.2-18.0), respectively. The mean SUVmean for primary tumor and atelectasis are 10.52.4 (range: 7.9-14.3) and 2.52.1(range: 1.3-6.7), respectively. Using paired t test, the difference between ADCmean values of PT and A is highly significant (PZ.0014). For SUVmax and SUVmean, the differences between PT and A are significant as well (PZ.019 and PZ.0017, respectively). Conclusions: Results of this pilot study demonstrate that both DW-MRI and PET/CT show significant differences between PT and A. DW MRI provides relevant functional imaging information for radiation therapy planning that needs to be investigated further. Author Disclosure: S. Saraiya: None. G. Hugo: None. K. Karki: None. K. Olsen: None. R. Groves: None. J. Ford: None. E. Weiss: E. Research Grant; NIH, Varian and Phillips Medical Systems. P. Royalty; UpToDate.
151 Prophylactic Irradiation of Surgical Tract Sites in the Era of Radical Pleurectomy for Malignant Pleural Mesothelioma Mesothelioma, Thymic Malignancies, and Other Thoracic Malignancies A.R. Barsky, J.P. Buckley, J.S. Friedberg, M. Culligan, S.M. Hahn, K.A. Cengel, and C.B. Simone; University of Pennsylvania, Philadelphia, PA Purpose/Objective(s): Radical pleurectomy (RP) is increasingly performed and has emerged as a standard definitive surgical treatment for resectable
152 The Important Prognostic Value of Pretreatment Stage in Patients Achieving Pathologic Complete Response After Neoadjuvant Therapy of Esophageal Cancer Mesothelioma, Thymic Malignancies, and Other Thoracic Malignancies J. Yang,1 Z. Xiao,1 L. Tan,1 Z. Zhou,1 Q. Feng,1 L. Wang,1 H. Zhang,1 D. Chen,1 J. Liang,1 Z. Hui,1 W. Yin,1 and J. He2; 1Department of Radiation Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences (CAMS), Peking Union Medical College (PUMC), Beijing, China, 2Department of Thoracic Surgical Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences (CAMS), Peking Union Medical College (PUMC), Beijing, China Purpose/Objective(s): To evaluate the relation between pretreatment stage and pathologic response as well as prognosis after neoadjuvant radiation therapy in esophageal squamous cell cancer (ESCC). Materials/Methods: A total of 296 ESCC patients treated by neoadjuvant radiation therapy in our center between 1980 and 2007 were retrospectively reviewed. The prescription doses were 36w50 Gy (median, 40 Gy), 2 Gy each daily, 5 fractions per week. Radiation therapy was delivered with anteroposterior opposing fields for most patients. Radiation treatment area encompassed primary tumor and relevant lymph node regions. All patients received esophagectomy and 2-field lymphadenectomy 4 weeks after