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Practice Change after Evaluation of an Offline Correction Protocol for Image-guided Radiotherapy in Head and Neck Cancer
Clinical Oncology 27 (2015) 750e755 Contents lists available at ScienceDirect
Clinical Oncology journal homepage: www.clinicaloncologyonline.net
Letters
Practice Change after Evaluation of an Offline Correction Protocol for Image-guided Radiotherapy in Head and Neck Cancer Madam d Image-guided radiotherapy is essential when verifying delivery of complex radiotherapy and is the UK standard of care for patients undergoing multi-fractionated treatments [1]. This study assessed the adequacy of planning margins and the effectiveness of an offline no action level (NAL) correction protocol in reducing geometric setup errors in patients undergoing radical radiotherapy for head and neck cancer at a single institution. Cone beam computed tomography images were fused with bone registries to obtain set-up data in the superioreinferior, anterioreposterior and lateral planes for 124 patients treated on two linear accelerators between January and December 2012. An offline NAL correction protocol with 0.3 cm tolerance was used. Population systematic (S) and random (s) errors were calculated following the initial three fractions pre-correction and for all images. Required clinical target volumeeplanning target volume (CTVePTV) margins for the whole patient population were generated using the Van Herk formula (2.5S þ 0.7s) [2]. Population set-up errors and required CTVePTV margins for the first three fractions pre-correction and for all fractions are shown in Table 1. The offline NAL correction protocol successfully identified and reduced systematic error. There was no effect on random error. The CTVePTV margins calculated suggested that the 0.3 cm margin in use at the time was inadequate and this has now been increased to 0.4 cm in all planes. Additionally, online imaging has been introduced for the first three fractions to account for the higher error observed during this period. This practice change highlights the importance of continual assessment
Table 1 Population set-up errors and margins
of local set-up protocols in line with current National Radiotherapy Implementation Group image-guided radiotherapy guidelines [1]. Previous studies have shown that daily online imaging in head and neck radiotherapy is effective in correcting random errors [3,4]. However, it is time consuming, labour intensive and exposes the patient to a higher imaging radiation dose. It may also allow reduced margins, which could have undesirable clinical consequences, as a larger CTVePTV margin accounts for other uncertainties such as delineation errors or microscopic disease [5]. Daily online imaging is used routinely in other UK centres, but data from this institution did not support its introduction for the whole course of treatment, as PTV coverage was adequate using an offline correction protocol. A regular review of set-up protocols and margins provides reassurance that a centre can deliver a plan accurately, but does not account for all sources of error. Target volume definition and patient selection have been highlighted as areas of weakness for which formal quality assurance protocols may also be beneficial [6], as an accurately delivered radiotherapy plan is of no use if it does not include the correct target or is delivered to an inappropriate patient. L. Forker*y1, J. Stratfordz1, P. Whitehurstx, N. Slevin*y, C. Anandadasy, A. Choudhury*y * The University of Manchester, Manchester Academic Health Science Centre, The Christie NHS Foundation Trust, Manchester, UK y Department of Clinical Oncology, The Christie NHS Foundation Trust, Manchester, UK z Wade Centre, Christie NHS Foundation Trust, The Christie NHS Foundation Trust, Manchester, UK x Christie Medical Physics & Engineering, Christie NHS Foundation Trust, The Christie NHS Foundation Trust, Manchester, UK
Errors and margins for patient population
Systematic error (S) Random error (s) Margin (2.5S þ 0.7s)
Lateral (cm)
Superiore inferior (cm)
Anteriore posterior (cm)
References
0.11 (0.17)
0.12 (0.16)
0.13 (0.18)
0.13 (0.13)
0.13 (0.13)
0.18 (0.18)
0.38 (0.52)
0.4 (0.5)
0.45 (0.58)
[1] National Cancer Action Team. National Radiotherapy Implementation Group Report. Image guided radiotherapy (IGRT) guidance for implementation and use. Available at: http://www. natcansat.nhs.uk/dhandler.ashx?d¼pubs&f¼National% 20Radiotherapy%20Implementation%20Group%20Report% 20IGRT%20Final.pdf; 2012.
Data shown in brackets are for the first three images precorrection.
1
Authors contributed equally to this work.
Letters / Clinical Oncology 27 (2015) 750e755 [2] van Herk M, Remeijer P, Rasch C, Lebesque JV. The probability of correct target dosage: dose-population histograms for deriving treatment margins in radiotherapy. Int J Radiat Oncol 2000;47(4):1121e1135. [3] Zeidan OA, Langen KM, Meeks SL, et al. Evaluation of imageguidance protocols in the treatment of head and neck cancers. Int J Radiat Oncol 2006;67(3):670e677. [4] Den RB, Doemer A, Kubicek G, et al. Daily image guidance with cone-beam computed tomography for head-and-neck cancer
751
intensity-modulated radiotherapy: a prospective study. Int J Radiat Oncol 2009;76(5):1353e1359. [5] Njeh CF. Tumor delineation: the weakest link in the search for accuracy in radiotherapy. J Med Phys 2008;33(4):136e140. [6] Roques T. Patient selection and radiotherapy volume definition e can we improve the weakest links in the treatment chain? Clin Oncol 2014;26:353e355.
http://dx.doi.org/10.1016/j.clon.2015.07.001 Crown Copyright Ó 2015 Published by Elsevier Ltd on behalf of The Royal College of Radiologists. All rights reserved.
Trainee Oncologists Experience of Flexible Nasal Endoscopy in the Head and Neck Clinic Madam d Flexible nasal endoscopy (FNE) is an essential tool in the joint head and neck cancer follow-up clinic to detect residual/recurrent disease, and is commonly carried out by both surgeons and oncologists. There is no national standard for attainment of FNE competency during ear, nose and throat (ENT) or oncology training. However, ENT trainees typically receive supervision in the technique from more senior trainees and may attend ‘introduction to ENT courses’; where they have the chance to practice in a supervised setting. They also commonly use FNE for the evaluation of non-malignant upper aerodigestive tract disease, and as a result rapidly achieve proficiency with this technique. We undertook a national survey of oncology trainees to determine their experience of performing FNE in the head and neck clinic, the effectiveness of the training they have received and what training they would ideally like. In total, 236 oncology trainee e-mail addresses, of a variety of training grades, taken from the MSc Oncology course database (conducted by the Institute of Cancer Research, UK) were e-mailed a nine-point questionnaire using SurveyMonkeyÒ
internet-based software (www.surverymoney.com); 110 trainees replied. 32 trainees had not undertaken a head and neck rotation and were excluded from the study. 23% of respondents felt confident in performing the procedure, with 60% asking for assistance on an at least weekly basis. For most of the trainees (62%), FNE training consisted of mere observation of the technique. When asked what FNE training respondents would like, there was a preference for locally delivered observation and supervision. It is our belief that FNE training for oncology trainees can be improved with locally delivered competency frameworks. In our unit we have introduced a FNE competency programme for new oncology trainees; with periods of observation, direct supervision, mentorship and use of local video and clinical image resources. J. Hughes, M.F. Ul Qamar, K. Shah, A. Salisbury Blenheim Head and Neck Unit, Churchill Hospital, Oxford, UK
http://dx.doi.org/10.1016/j.clon.2015.08.004 Ó 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.
Neoadjuvant Chemotherapy in Technically Unresectable Oral Cancers: Does Human Papillomavirus Make a Difference? Madam d Human papillomavirus (HPV) positivity confers a favourable prognosis in oropharyngeal tumours treated with chemoradiation or radiation [1e4]. However, the positive effect of HPV is negated by increasing stage and increasing tobacco exposure [3,5]. At our centre, we treat borderline resectable or technically unresectable oral cancers (TURO) with two cycles of Neoadjuvant chemotherapy (NACT) followed by an assessment for surgery [6].
As these patients had T4 disease and are often exposed to oral tobacco, we believed that HPV positivity would not have any effect in this cohort of patients. We have tested this hypothesis in 124 patients with TURO treated with NACT. HPV positivity was identified by p16 immunohistochemistry on the pretreatment biopsy. In total, 16 patients were HPV positive (12.9%). Table 1 shows the baseline patient parameters and NACT details
Clinical Oncology journal homepage: www.clinicaloncologyonline.net
Letters
Practice Change after Evaluation of an Offline Correction Protocol for Image-guided Radiotherapy in Head and Neck Cancer Madam d Image-guided radiotherapy is essential when verifying delivery of complex radiotherapy and is the UK standard of care for patients undergoing multi-fractionated treatments [1]. This study assessed the adequacy of planning margins and the effectiveness of an offline no action level (NAL) correction protocol in reducing geometric setup errors in patients undergoing radical radiotherapy for head and neck cancer at a single institution. Cone beam computed tomography images were fused with bone registries to obtain set-up data in the superioreinferior, anterioreposterior and lateral planes for 124 patients treated on two linear accelerators between January and December 2012. An offline NAL correction protocol with 0.3 cm tolerance was used. Population systematic (S) and random (s) errors were calculated following the initial three fractions pre-correction and for all images. Required clinical target volumeeplanning target volume (CTVePTV) margins for the whole patient population were generated using the Van Herk formula (2.5S þ 0.7s) [2]. Population set-up errors and required CTVePTV margins for the first three fractions pre-correction and for all fractions are shown in Table 1. The offline NAL correction protocol successfully identified and reduced systematic error. There was no effect on random error. The CTVePTV margins calculated suggested that the 0.3 cm margin in use at the time was inadequate and this has now been increased to 0.4 cm in all planes. Additionally, online imaging has been introduced for the first three fractions to account for the higher error observed during this period. This practice change highlights the importance of continual assessment
Table 1 Population set-up errors and margins
of local set-up protocols in line with current National Radiotherapy Implementation Group image-guided radiotherapy guidelines [1]. Previous studies have shown that daily online imaging in head and neck radiotherapy is effective in correcting random errors [3,4]. However, it is time consuming, labour intensive and exposes the patient to a higher imaging radiation dose. It may also allow reduced margins, which could have undesirable clinical consequences, as a larger CTVePTV margin accounts for other uncertainties such as delineation errors or microscopic disease [5]. Daily online imaging is used routinely in other UK centres, but data from this institution did not support its introduction for the whole course of treatment, as PTV coverage was adequate using an offline correction protocol. A regular review of set-up protocols and margins provides reassurance that a centre can deliver a plan accurately, but does not account for all sources of error. Target volume definition and patient selection have been highlighted as areas of weakness for which formal quality assurance protocols may also be beneficial [6], as an accurately delivered radiotherapy plan is of no use if it does not include the correct target or is delivered to an inappropriate patient. L. Forker*y1, J. Stratfordz1, P. Whitehurstx, N. Slevin*y, C. Anandadasy, A. Choudhury*y * The University of Manchester, Manchester Academic Health Science Centre, The Christie NHS Foundation Trust, Manchester, UK y Department of Clinical Oncology, The Christie NHS Foundation Trust, Manchester, UK z Wade Centre, Christie NHS Foundation Trust, The Christie NHS Foundation Trust, Manchester, UK x Christie Medical Physics & Engineering, Christie NHS Foundation Trust, The Christie NHS Foundation Trust, Manchester, UK
Errors and margins for patient population
Systematic error (S) Random error (s) Margin (2.5S þ 0.7s)
Lateral (cm)
Superiore inferior (cm)
Anteriore posterior (cm)
References
0.11 (0.17)
0.12 (0.16)
0.13 (0.18)
0.13 (0.13)
0.13 (0.13)
0.18 (0.18)
0.38 (0.52)
0.4 (0.5)
0.45 (0.58)
[1] National Cancer Action Team. National Radiotherapy Implementation Group Report. Image guided radiotherapy (IGRT) guidance for implementation and use. Available at: http://www. natcansat.nhs.uk/dhandler.ashx?d¼pubs&f¼National% 20Radiotherapy%20Implementation%20Group%20Report% 20IGRT%20Final.pdf; 2012.
Data shown in brackets are for the first three images precorrection.
1
Authors contributed equally to this work.
Letters / Clinical Oncology 27 (2015) 750e755 [2] van Herk M, Remeijer P, Rasch C, Lebesque JV. The probability of correct target dosage: dose-population histograms for deriving treatment margins in radiotherapy. Int J Radiat Oncol 2000;47(4):1121e1135. [3] Zeidan OA, Langen KM, Meeks SL, et al. Evaluation of imageguidance protocols in the treatment of head and neck cancers. Int J Radiat Oncol 2006;67(3):670e677. [4] Den RB, Doemer A, Kubicek G, et al. Daily image guidance with cone-beam computed tomography for head-and-neck cancer
751
intensity-modulated radiotherapy: a prospective study. Int J Radiat Oncol 2009;76(5):1353e1359. [5] Njeh CF. Tumor delineation: the weakest link in the search for accuracy in radiotherapy. J Med Phys 2008;33(4):136e140. [6] Roques T. Patient selection and radiotherapy volume definition e can we improve the weakest links in the treatment chain? Clin Oncol 2014;26:353e355.
http://dx.doi.org/10.1016/j.clon.2015.07.001 Crown Copyright Ó 2015 Published by Elsevier Ltd on behalf of The Royal College of Radiologists. All rights reserved.
Trainee Oncologists Experience of Flexible Nasal Endoscopy in the Head and Neck Clinic Madam d Flexible nasal endoscopy (FNE) is an essential tool in the joint head and neck cancer follow-up clinic to detect residual/recurrent disease, and is commonly carried out by both surgeons and oncologists. There is no national standard for attainment of FNE competency during ear, nose and throat (ENT) or oncology training. However, ENT trainees typically receive supervision in the technique from more senior trainees and may attend ‘introduction to ENT courses’; where they have the chance to practice in a supervised setting. They also commonly use FNE for the evaluation of non-malignant upper aerodigestive tract disease, and as a result rapidly achieve proficiency with this technique. We undertook a national survey of oncology trainees to determine their experience of performing FNE in the head and neck clinic, the effectiveness of the training they have received and what training they would ideally like. In total, 236 oncology trainee e-mail addresses, of a variety of training grades, taken from the MSc Oncology course database (conducted by the Institute of Cancer Research, UK) were e-mailed a nine-point questionnaire using SurveyMonkeyÒ
internet-based software (www.surverymoney.com); 110 trainees replied. 32 trainees had not undertaken a head and neck rotation and were excluded from the study. 23% of respondents felt confident in performing the procedure, with 60% asking for assistance on an at least weekly basis. For most of the trainees (62%), FNE training consisted of mere observation of the technique. When asked what FNE training respondents would like, there was a preference for locally delivered observation and supervision. It is our belief that FNE training for oncology trainees can be improved with locally delivered competency frameworks. In our unit we have introduced a FNE competency programme for new oncology trainees; with periods of observation, direct supervision, mentorship and use of local video and clinical image resources. J. Hughes, M.F. Ul Qamar, K. Shah, A. Salisbury Blenheim Head and Neck Unit, Churchill Hospital, Oxford, UK
http://dx.doi.org/10.1016/j.clon.2015.08.004 Ó 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.
Neoadjuvant Chemotherapy in Technically Unresectable Oral Cancers: Does Human Papillomavirus Make a Difference? Madam d Human papillomavirus (HPV) positivity confers a favourable prognosis in oropharyngeal tumours treated with chemoradiation or radiation [1e4]. However, the positive effect of HPV is negated by increasing stage and increasing tobacco exposure [3,5]. At our centre, we treat borderline resectable or technically unresectable oral cancers (TURO) with two cycles of Neoadjuvant chemotherapy (NACT) followed by an assessment for surgery [6].
As these patients had T4 disease and are often exposed to oral tobacco, we believed that HPV positivity would not have any effect in this cohort of patients. We have tested this hypothesis in 124 patients with TURO treated with NACT. HPV positivity was identified by p16 immunohistochemistry on the pretreatment biopsy. In total, 16 patients were HPV positive (12.9%). Table 1 shows the baseline patient parameters and NACT details