Medicine and Health Sciences Commons^™

Is Extended Volume External Beam Radiation Therapy Covering The Anastomotic Site Beneficial In Post-Esophagectomy High Risk Patients?, Edward Yu, Rashid Dar, George Rodrigues, Larry Stitt, Gregory Videtic, Pauline Truong, Anna Tomiak, Robert Ash, Ed Brecevic, Richard Inculet, Richard Malthaner, Mark Vincent, Ian Craig, Walter Kocha, Michael Lefcoe

Richard A. Malthaner

Background and purpose: To assess the impact of extended volume radiation therapy (RT) with anastomotic coverage on local control in high risk post-operative esophageal cancer patients.

Patients and methods: This is a retrospective study of high risk (T(3), T(4), nodes positive, with or without margin involvement) post-operative esophageal cancer patients treated at London Regional Cancer Centre from 1989 to 1999. After esophagectomy, all patients received adjuvant combined modality therapy consisting of four cycles of fluorouracil-based chemotherapy, and loco-regional RT with or without coverage of the anastomotic site. RT dose ranged from 45 to 60 Gy at 1.8-2.0 Gy/fraction with treatment …

Neoadjuvant Or Adjuvant Therapy For Resectable Esophageal Cancer: A Systematic Review And Meta-Analysis, Richard Malthaner, Rebecca Wong, R. Rumble, Lisa Zuraw

Richard A. Malthaner

Background: Carcinoma of the esophagus is an aggressive malignancy with an increasing incidence. Its virulence, in terms of symptoms and mortality, justifies a continued search for optimal therapy. The large and growing number of patients affected, the high mortality rates, the worldwide geographic variation in practice, and the large body of good quality research warrants a systematic review with meta-analysis.

Methods: A systematic review and meta-analysis investigating the impact of neoadjuvant or adjuvant therapy on resectable thoracic esophageal cancer to inform evidence-based practice was produced.MEDLINE, CANCERLIT, Cochrane Library, EMBASE, and abstracts from the American Society of Clinical Oncology and the …

Neoadjuvant Or Adjuvant Therapy For Resectable Esophageal Cancer: A Clinical Practice Guideline, Richard Malthaner, Rebecca Wong, R. Rumble, Lisa Zuraw

Richard A. Malthaner

Background: Carcinoma of the esophagus is an aggressive malignancy with an increasing incidence. Its virulence, in terms of symptoms and mortality, justifies a continued search for optimal therapy. A clinical practice guideline was developed based on a systematic review investigating neoadjuvant or adjuvant therapy on resectable thoracic esophageal cancer. Methods: A systematic review with meta-analysis was developed and clinical recommendations were drafted. External review of the practice guideline report by practitioners in Ontario, Canada was obtained through a mailed survey, and incorporated. Final approval of the practice guideline was obtained from the Practice Guidelines Coordinating Committee. Results: The systematic review …

Is Extended Volume External Beam Radiation Therapy Covering The Anastomotic Site Beneficial In Post-Esophagectomy High Risk Patients?, Edward Yu, Rashid Dar, George Rodrigues, Larry Stitt, Gregory Videtic, Pauline Truong, Anna Tomiak, Robert Ash, Ed Brecevic, Richard Inculet, Richard Malthaner, Mark Vincent, Ian Craig, Walter Kocha, Michael Lefcoe

Richard A. Malthaner

Background and purpose: To assess the impact of extended volume radiation therapy (RT) with anastomotic coverage on local control in high risk post-operative esophageal cancer patients.

Patients and methods: This is a retrospective study of high risk (T(3), T(4), nodes positive, with or without margin involvement) post-operative esophageal cancer patients treated at London Regional Cancer Centre from 1989 to 1999. After esophagectomy, all patients received adjuvant combined modality therapy consisting of four cycles of fluorouracil-based chemotherapy, and loco-regional RT with or without coverage of the anastomotic site. RT dose ranged from 45 to 60 Gy at 1.8-2.0 Gy/fraction with treatment …

Subsets More Likely To Benefit From Surgery Or Prophylactic Cranial Irradiation After Chemoradiation For Localized Non-Small-Cell Lung Cancer, Bruce Keith, Mark Vincent, Larry Stitt, Anna Tomiak, Richard Malthaner, Edward Yu, Pauline Truong, Richard Inculet, Michael Lefcoe, A. Dar, Walter Kocha, Ian Craig

Richard A. Malthaner

After chemoradiation for localized non-small-cell lung cancer, surgery and prophylactic cranial irradiation (PCI) have been used as additional therapies. Less than a third of patients develop brain recurrences, or have local recurrence as their sole initial site of recurrence; these are groups that would benefit from PCI or surgery, respectively. Pretreatment identification of patients more likely to benefit from surgery or PCI would be useful. A retrospective analysis of 80 patients was performed to determine prognostic factors for such patterns of failure. Twenty-nine patients were subsequently selected for surgery in a nonrandomized manner. Seventeen patients had isolated local initial recurrence …

Neoadjuvant Or Adjuvant Therapy For Resectable Esophageal Cancer: A Systematic Review And Meta-Analysis, Richard Malthaner, Rebecca Wong, R. Rumble, Lisa Zuraw

Richard A. Malthaner

Background: Carcinoma of the esophagus is an aggressive malignancy with an increasing incidence. Its virulence, in terms of symptoms and mortality, justifies a continued search for optimal therapy. The large and growing number of patients affected, the high mortality rates, the worldwide geographic variation in practice, and the large body of good quality research warrants a systematic review with meta-analysis.

Methods: A systematic review and meta-analysis investigating the impact of neoadjuvant or adjuvant therapy on resectable thoracic esophageal cancer to inform evidence-based practice was produced.MEDLINE, CANCERLIT, Cochrane Library, EMBASE, and abstracts from the American Society of Clinical Oncology and the …

Neoadjuvant Or Adjuvant Therapy For Resectable Esophageal Cancer: A Clinical Practice Guideline, Richard Malthaner, Rebecca Wong, R. Rumble, Lisa Zuraw

Richard A. Malthaner

Background: Carcinoma of the esophagus is an aggressive malignancy with an increasing incidence. Its virulence, in terms of symptoms and mortality, justifies a continued search for optimal therapy. A clinical practice guideline was developed based on a systematic review investigating neoadjuvant or adjuvant therapy on resectable thoracic esophageal cancer.

Methods: A systematic review with meta-analysis was developed and clinical recommendations were drafted. External review of the practice guideline report by practitioners in Ontario, Canada was obtained through a mailed survey, and incorporated. Final approval of the practice guideline was obtained from the Practice Guidelines Coordinating Committee.

Results: The systematic review …

Subsets More Likely To Benefit From Surgery Or Prophylactic Cranial Irradiation After Chemoradiation For Localized Non-Small-Cell Lung Cancer, Bruce Keith, Mark Vincent, Larry Stitt, Anna Tomiak, Richard Malthaner, Edward Yu, Pauline Truong, Richard Inculet, Michael Lefcoe, A. Dar, Walter Kocha, Ian Craig

Richard A. Malthaner

After chemoradiation for localized non-small-cell lung cancer, surgery and prophylactic cranial irradiation (PCI) have been used as additional therapies. Less than a third of patients develop brain recurrences, or have local recurrence as their sole initial site of recurrence; these are groups that would benefit from PCI or surgery, respectively. Pretreatment identification of patients more likely to benefit from surgery or PCI would be useful. A retrospective analysis of 80 patients was performed to determine prognostic factors for such patterns of failure. Twenty-nine patients were subsequently selected for surgery in a nonrandomized manner. Seventeen patients had isolated local initial recurrence …

Prophylactic Cranial Irradiation For Patients With Limited-Stage Small-Cell Lung Cancer With Response To Chemoradiation, Patricia Tai, Avi Assouline, Kurian Joseph, Larry Stitt, Edward Yu

Edward Yu

Background Previous clinical studies have generally reported that prophylactic cranial irradiation (PCI) was given to patients with a complete response (CR) to chemotherapy and chest radiotherapy in limited-stage small-cell lung cancer (SCLC). It is not clear if those with incomplete response (IR) would benefit from PCI. Patients and Methods The Saskatchewan experience from 1981 through 2007 was reviewed. Patients were treated with chest radiotherapy and chemotherapy with or without PCI (typical doses: 2500 cGy in 10 fractions over 2 weeks, 3000 cGy in 15 fractions over 3 weeks, or 3000 cGy in 10 fractions over 2 weeks). Results There were …

The Impact Of Post-Mastectomy Radiation Therapy On Male Breast Cancer Patients--A Case Series, Edward Yu, Hiromichi Suzuki, Jawaid Younus, Tarek Elfiki, Larry Stitt, Gary Yau, Olga Vujovic, Francisco Perera, Michael Lock, Patricia Tai

Michael Lock

OBJECTIVE: To assess the impact of radiation management on male breast cancer (MBC) at London Regional Cancer Program (LRCP).

METHODS AND MATERIALS: Men with a diagnosis of breast cancer referred to LRCP were reviewed. The seventh American Joint Committee on Cancer staging system was used. Patients treated with and without post-mastectomy radiation therapy (PMRT) were analyzed. Disease-free survival (DFS) was defined as time duration from diagnosis to first recurrence. Overall survival (OS) was defined as time duration from pathologic diagnosis to death or last follow-up with any death defined as an event. Survival estimates were obtained using Kaplan-Meier methodology.

RESULTS: …

Prediction Of Radiation Pneumonitis By Dose-Volume Histogram Parameters In Lung Cancer--A Systematic Review, George Rodrigues, Michael Lock, David D'Souza, Edward Yu, Jake Van Dyk

Michael Lock

BACKGROUND AND PURPOSE: To perform a systematic review of the predictive ability of various dose-volume histogram (DVH) parameters (V(dose), mean lung dose (MLD), and normal tissue complication probability (NTCP)) in the incidence of radiation pneumonitis (RP) caused by external-beam radiation therapy.

METHODS AND MATERIALS: Studies assessing the relationship between CT-based DVH reduction parameters and RP rate in radically treated lung cancer were eligible for the review. Synonyms for RP, lung cancer, DVH and its associated parameters (NTCP, V(20), V(30), MLD) were combined in a search strategy involving electronic databases, secondary reference searching, and consultation with experts. Individual or group data …

Mesothelioma - Epidemiology And Management, Patricia Tai, Edward Yu, Avi Assouline, Kurian Joseph

Edward Yu

Mesothelioma is an uncommon tumor. It has a latency period of 20-40 years. The most important risk factor is asbestos exposure. Prognosis of mesothelioma is generally poor with high case-fatality rate, and research to improve the outcome of this disease is on-going worldwide. Due to its rarity, management by a multidisciplinary team with experience is recommended. Carefully selected patients may benefit from tri-modality (surgery, radiotherapy and chemotherapy) treatment. The management of pleural and peritoneal mesothelioma is summarized in this review. Recent advances in chemotherapy and biologic response modifiers are promising.

The Impact Of Post-Mastectomy Radiation Therapy On Male Breast Cancer Patients--A Case Series, Edward Yu, Hiromichi Suzuki, Jawaid Younus, Tarek Elfiki, Larry Stitt, Gary Yau, Olga Vujovic, Francisco Perera, Michael Lock, Patricia Tai

Edward Yu

OBJECTIVE: To assess the impact of radiation management on male breast cancer (MBC) at London Regional Cancer Program (LRCP). METHODS AND MATERIALS: Men with a diagnosis of breast cancer referred to LRCP were reviewed. The seventh American Joint Committee on Cancer staging system was used. Patients treated with and without post-mastectomy radiation therapy (PMRT) were analyzed. Disease-free survival (DFS) was defined as time duration from diagnosis to first recurrence. Overall survival (OS) was defined as time duration from pathologic diagnosis to death or last follow-up with any death defined as an event. Survival estimates were obtained using Kaplan-Meier methodology. RESULTS: …

The Use Of Ct Density Changes At Internal Tissue Interfaces To Correlate Internal Organ Motion With An External Surrogate, Stewart Gaede, Gregory Carnes, Edward Yu, Jake Van Dyk, Jerry Battista, Ting-Yim Lee

Edward Yu

The purpose of this paper is to describe a non-invasive method to monitor the motion of internal organs affected by respiration without using external markers or spirometry, to test the correlation with external markers, and to calculate any time shift between the datasets. Ten lung cancer patients were CT scanned with a GE LightSpeed Plus 4-Slice CT scanner operating in a ciné mode. We retrospectively reconstructed the raw CT data to obtain consecutive 0.5 s reconstructions at 0.1 s intervals to increase image sampling. We defined regions of interest containing tissue interfaces, including tumour/lung interfaces that move due to breathing …

Post-Operative Extended Volume External Beam Radiation Therapy In High Risk Esophageal Cancer Patients: A Prospective Experience, E. Yu, P. Tai, J. Younus, R. Malthaner, P. Truong, L. Stitt, G. Rodrigues, R. Ash, R. Dar, B. Yaremko, A. Tomiak, B. Dingle, M. Sanatani, M. Vincent, W. Kocha, D. Fortin, R. Inculet

Edward Yu

Background and purpose: Extended volume external beam radiation therapy (RT) following esophagectomy is controversial. This prospective study evaluates the feasibility of extended volume RT treatment in high-risk esophagectomy patients with cervical anastomosis receiving post–operative combined chemo-radiation therapy. Patients and methods: From 2001-2006, 15 patients with resected esophageal cancer were prospectively accrued to this pilot study, to evaluate the adverse effects of extended volume RT. Eligibility criteria were pathologically proven esophageal malignancy, T3-4, N0-1, disease amenable to surgical resection and esophagectomy with or without resection margin involvement. Patients with distant metastases (M1) and patients treated with previous RT were excluded. All …

Nodal Ratios In Node-Positive Breast Cancer—Long-Term Study To Clarify Discrepancy Of Role Of Supraclavicular And Axillary Regional Radiotherapy, Patricia Tai, Kurian Joseph, Evgeny Sadikov, Shazia Mahmood, Francis Lien, Edward Yu

Edward Yu

Purpose: To study the absolute number of involved nodes/the number of nodes examined or the nodal ratio (NR) in breast cancer. The primary study endpoint was to evaluate the role of supraclavicular and axillary radiotherapy (SART) according to the NR. Methods and materials: From the Saskatchewan provincial registry of 1981-1995, the charts of 5,996 consecutive patients were retrieved to collect detailed prognostic factors. Among these patients, 1,985 were node positive. Because the NRs are more reliable the greater the number of nodes examined, we analyzed 1,255 patients with > or =10 nodes examined. Of these 1,255 patients, 667, 389, and 199 …

The Role Of Radiation Therapy In Malignant Pleural Mesothelioma: A Systematic Review, Yee Ung, Edward Yu, Conrad Falkson, Adam Haynes, Denise Stys-Norman, William Evans

Edward Yu

Introduction: Radiation therapy may offer patients presenting with malignant pleural mesothelioma (MPM) symptom palliation and improvements in quality of life. This systematic review will address the role of radiation therapy in the management of MPM. Methods: A thorough systematic search of the literature was conducted for published articles and conference proceedings for applicable abstracts. Relevant trials were selected and assessed. Results: Three small randomized controlled trials compared prophylactic external beam radiation therapy to no radiation therapy for patients with thoracic tracts caused by drainage tubes or diagnostic procedures. None of those trials reported any serious adverse effects. A pooled analysis …

Comparative Planning Evaluation Of Intensity-Modulated Radiotherapy Techniques For Complex Lung Cancer Cases, Slav Yartsev, Jeff Chen, Edward Yu, Tomas Kron, George Rodrigues, Terry Coad, Kristina Trenka, Eugene Wong, Glenn Bauman, Jake Van Dyk

Edward Yu

Background and purpose: Lung cancer treatment can be one of the most challenging fields in radiotherapy. The aim of the present study was to compare different modalities of radiation delivery based on a balanced scoring scheme for target coverage and normal tissue avoidance. Patients and methods: Treatment plans were developed for 15 patients with stage III inoperable non-small cell lung cancer using 3D conformal technique and intensity-modulated radiotherapy (IMRT). Elective nodal irradiation was included for all cases to create the most challenging scenarios with large target volumes. A 2 cm margin was used around the gross tumour volume (GTV) to …

The Role Of Radiation Therapy On Medically Inoperable Clinically Localized Non-Small Cell Lung Patients: London Regional Cancer Program (Lrcp) Clinical Experience, Michael Lee, Edward Yu, Robert Ash, Patricia Tai, Larry Stitt, George Rodrigues, Rashid Dar, Mark Vincent, Richard Inculet, Richard Malthaner

Edward Yu

Lung cancer is the most frequent cause of cancer death in both men and women in North America. In 2006, an estimated 22,700 Canadians will be diagnosed with lung cancer and 19,300 will die of it (Canadian Cancer Statistics 2006). Approximately 15-20% of NSCLC patients present with early or localized disease. Surgical resection of T1-2N0 NSCLC remains the treatment of choice for this population, and results in a 5-year survival rate of 50-70%. Patients deemed medically inoperable have been treated with non-surgical therapies, such as radiation therapy(RT), while some patients have simply been observed without any tumor therapy because of …

Radiotherapy For Merkel Cell Carcinoma Of The Skin, Patricia Tai, Edward Yu, Juan Pacella

Edward Yu

We examine the impact of radiotherapy in the treatment of Merkel cell carcinoma (MCC) of the skin. Data at two Canadian institutions (Allan Blair Cancer Centre and London Regional Cancer Program) were collected and charts were retrieved from the registry of 1987 to 2005. A total of 79 patients with definite MCC were studied. All except three had a primary skin lesion. Six patients presented with nodal metastases and three patients with distant metastases. Fourteen patients were referred to the cancer centers at the time of recurrence: 2/14 with local recurrence, 8/14 with nodal recurrence, 2/14 with both local and …

Is Extended Volume External Beam Radiation Therapy Covering The Anastomotic Site Beneficial In Post-Esophagectomy High Risk Patients?, Edward Yu, Rashid Dar, George Rodrigues, Larry Stitt, Gregory Videtic, Pauline Truong, Anna Tomiak, Robert Ash, Ed Brecevic, Richard Inculet, Richard Malthaner, Mark Vincent, Ian Craig, Walter Kocha, Michael Lefcoe

Edward Yu

Background and purpose: To assess the impact of extended volume radiation therapy (RT) with anastomotic coverage on local control in high risk post-operative esophageal cancer patients. Patients and methods: This is a retrospective study of high risk (T(3), T(4), nodes positive, with or without margin involvement) post-operative esophageal cancer patients treated at London Regional Cancer Centre from 1989 to 1999. After esophagectomy, all patients received adjuvant combined modality therapy consisting of four cycles of fluorouracil-based chemotherapy, and loco-regional RT with or without coverage of the anastomotic site. RT dose ranged from 45 to 60 Gy at 1.8-2.0 Gy/fraction with treatment …

Planning Evaluation Of Radiotherapy For Complex Lung Cancer Cases Using Helical Tomotherapy, Tomas Kron, Grigor Grigorov, Edward Yu, Slav Yartsev, Jeff Chen, Eugene Wong, George Rodrigues, Kris Trenka, Terry Coad, Glenn Bauman, Jake Van Dyk

Edward Yu

Lung cancer treatment is one of the most challenging fields in radiotherapy. The aim of the present study was to investigate what role helical tomotherapy (HT), a novel approach to the delivery of highly conformal dose distributions using intensity-modulated radiation fan beams, can play in difficult cases with large target volumes typical for many of these patients. Tomotherapy plans were developed for 15 patients with stage III inoperable non-small-cell lung cancer. While not necessarily clinically indicated, elective nodal irradiation was included for all cases to create the most challenging scenarios with large target volumes. A 2 cm margin was used …

Prediction Of Radiation Pneumonitis By Dose-Volume Histogram Parameters In Lung Cancer--A Systematic Review, George Rodrigues, Michael Lock, David D'Souza, Edward Yu, Jake Van Dyk

Edward Yu

BACKGROUND AND PURPOSE: To perform a systematic review of the predictive ability of various dose-volume histogram (DVH) parameters (V(dose), mean lung dose (MLD), and normal tissue complication probability (NTCP)) in the incidence of radiation pneumonitis (RP) caused by external-beam radiation therapy. METHODS AND MATERIALS: Studies assessing the relationship between CT-based DVH reduction parameters and RP rate in radically treated lung cancer were eligible for the review. Synonyms for RP, lung cancer, DVH and its associated parameters (NTCP, V(20), V(30), MLD) were combined in a search strategy involving electronic databases, secondary reference searching, and consultation with experts. Individual or group data …

Radiation Treatment Of Lung Cancer--Patterns Of Practice In Canada, Patricia Tai, Edward Yu, Jerry Battista, Jake Van Dyk

Edward Yu

BACKGROUND AND PURPOSE: To assess the patterns of practice among Canadian radiation oncologists who treat lung cancers. PATIENTS AND METHODS: A questionnaire detailing different aspects of radiation treatment of lung cancer was mailed to all radiation oncologists treating lung cancer in Canada. Seventy-two percent (74/103) of radiation oncologists who treat lung cancer from all 34 Canadian cancer centres replied to the questionnaire. RESULTS: (a) Radiotherapy regimens in Canadian cancer centres are in accordance with several major randomised studies. There is still some variation in treatment practice that may be due to unresolved controversies or limited resources. The most frequently used …

Continued Cigarette Smoking By Patients Receiving Concurrent Chemoradiotherapy For Limited-Stage Small-Cell Lung Cancer Is Associated With Decreased Survival, Gregory Videtic, Larry Stitt, A. Dar, Walter Kocha, Anna Tomiak, Pauline Truong, Mark Vincent, Edward Yu

Edward Yu

PURPOSE: To determine the impact of continued smoking by patients receiving chemotherapy (CHT) and radiotherapy (RT) for limited-stage small-cell lung cancer (LSCLC) on toxicity and survival. PATIENTS AND METHODS: A retrospective review was carried out on 215 patients with LSCLC treated between 1989 and 1999. Treatment consisted of six cycles of alternating cyclophosphamide, doxorubicin, vincristine and etoposide, cisplatin (EP). Thoracic RT was concurrent with EP (cycle 2 or 3) only. Patients were known smokers, with their smoking status recorded at the start of chemoradiotherapy (CHT/RT). RT interruption during concurrent CHT/RT was used as the marker for treatment toxicity. RESULTS: Of …

Subsets More Likely To Benefit From Surgery Or Prophylactic Cranial Irradiation After Chemoradiation For Localized Non-Small-Cell Lung Cancer, Bruce Keith, Mark Vincent, Larry Stitt, Anna Tomiak, Richard Malthaner, Edward Yu, Pauline Truong, Richard Inculet, Michael Lefcoe, A. Dar, Walter Kocha, Ian Craig

Edward Yu

After chemoradiation for localized non-small-cell lung cancer, surgery and prophylactic cranial irradiation (PCI) have been used as additional therapies. Less than a third of patients develop brain recurrences, or have local recurrence as their sole initial site of recurrence; these are groups that would benefit from PCI or surgery, respectively. Pretreatment identification of patients more likely to benefit from surgery or PCI would be useful. A retrospective analysis of 80 patients was performed to determine prognostic factors for such patterns of failure. Twenty-nine patients were subsequently selected for surgery in a nonrandomized manner. Seventeen patients had isolated local initial recurrence …

Improving The Consistency In Cervical Esophageal Target Volume Definition By Special Training, Patricia Tai, Jake Van Dyk, Jerry Battista, Edward Yu, Larry Stitt, Jon Tonita, Olusegun Agboola, James Brierley, Rashid Dar, Christopher Leighton, Shawn Malone, Barbara Strang, Pauline Truong, Gregory Videtic, C. Wong, Rebecca Wong, Youssef Youssef

Edward Yu

PURPOSE: Three-dimensional conformal radiation therapy requires the precise definition of the target volume. Its potential benefits could be offset by the inconsistency in target definition by radiation oncologists. In a previous survey of radiation oncologists, a large degree of variation in target volume definition of cervical esophageal cancer was noted for the boost phase of radiotherapy. The present study evaluated whether special training could improve the consistency in target volume definitions. METHODS AND MATERIALS: A pre-training survey was performed to establish baseline values. This was followed by a special one-on-one training session on treatment planning based on the RTOG 94-05 …

Variability Of Target Volume Delineation In Cervical Esophageal Cancer, Patricia Tai, Jake Van Dyk, Edward Yu, Jerry Battista, Larry Stitt, Terry Coad

Edward Yu

PURPOSE: Three-dimensional (3D) conformal radiation therapy (CRT) assumes and requires the precise delineation of the target volume. To assess the consistency of target volume delineation by radiation oncologists, who treat esophageal cancers, we have performed a transCanada survey. MATERIALS AND METHODS: One of three case presentations, including CT scan images, of different stages of cervical esophageal cancer was randomly chosen and sent by mail. Respondents were asked to fill in questionnaires regarding treatment techniques and to outline boost target volumes for the primary tumor on CT scans, using ICRU-50 definitions. RESULTS: Of 58 radiation oncologists who agreed to participate, 48 …