Hannah Carolan

Whole brain radiotherapy with hippocampal avoidance and simultaneous integrated boost for 1-3 brain metastases: a feasibility study using volumetric modulated arc therapy.

PURPOSE To evaluate the feasibility of using volumetric modulated arc therapy (VMAT) to deliver whole brain radiotherapy (WBRT) with hippocampal avoidance and a simultaneous integrated boost (SIB) for one to three brain metastases. METHODS AND MATERIALS Ten patients previously treated with stereotactic radiosurgery for one to three brain metastases underwent repeat planning using VMAT. The whole brain prescription dose was 32.25 Gy in 15 fractions, and SIB doses to brain metastases were 63 Gy to lesions >or=2.0 cm and 70.8 Gy to lesions <2.0 cm in diameter. The mean dose to the hippocampus was kept at <6 Gy(2). Plans were optimized for conformity and target coverage while minimizing hippocampal and ocular doses. Plans were evaluated on target coverage, prescription isodose to target volume ratio, conformity number, homogeneity index, and maximum dose to prescription dose ratio. RESULTS Ten patients had 18 metastases. Mean values for the brain metastases were as follows: conformity number = 0.73 +/- 0.10, target coverage = 0.98 +/- 0.01, prescription isodose to target volume = 1.34 +/- 0.19, maximum dose to prescription dose ratio = 1.09 +/- 0.02, and homogeneity index = 0.07 +/- 0.02. For the whole brain, the mean target coverage and homogeneity index were 0.960 +/- 0.002 and 0.39 +/- 0.06, respectively. The mean hippocampal dose was 5.23 +/- 0.39 Gy(2). The mean treatment delivery time was 3.6 min (range, 3.3-4.1 min). CONCLUSIONS VMAT was able to achieve adequate whole brain coverage with conformal hippocampal avoidance and radiosurgical quality dose distributions for one to three brain metastases. The mean delivery time was under 4 min.

The Impact of Peer Review of Volume Delineation in Stereotactic Body Radiation Therapy Planning for Primary Lung Cancer: A Multicenter Quality Assurance Study

Introduction: Although the value of peer review is increasingly recognized, there is little research documenting its impact in the setting of stereotactic body radiation therapy (SBRT) for lung cancer. This study determines the dosimetric effect of peer review of tumor and normal tissue contouring in lung SBRT planning. Methods: Forty anonymized lung SBRT plans were retrospectively evaluated post treatment. Each plan was independently reviewed by two to three radiation oncologists using established institutional guidelines. For each structure, reviewers recorded recommendations for “no change,” “minor change,” “major change,” or “missing contour” and provided a modified or new contour as needed. Dose–volume histograms were analyzed for dosimetric violations. Results: Among 472 contoured structures evaluated, recommendations from peer review were 107 major change (23%), 176 minor change (37%), 157 no change (33%), and 32 missing (7%). Common major changes involved the skin (n = 20), heart (n = 18), and proximal bronchial tree (n = 15). Dose constraints were not achieved for 25 new or recontoured structures (5%), of which 17 involved the planning target volume (PTV). Among cases with PTV violations, the mean prescription dose coverage to the modified PTVs was 90%, compared with the protocol standard of greater than or equal to 95% coverage. The remaining violations involved the ribs (n = 5), spinal canal (n = 2), and heart (n = 1). Conclusions: Peer review of structure contouring resulted in significant changes in lung SBRT plans. Recontouring of several plans revealed violations of dose limits, most often involving inadequate PTV coverage. Peer review, especially of target volume delineation, is warranted to improve consistency and quality in lung SBRT planning.

Thymoma: A Population-Based Study of the Management and Outcomes for the Province of British Columbia

Introduction: Thymomas are rare neoplasms with variable clinical behavior. Our primary study aim was to analyze treatment practices and outcomes in a population-based cohort of thymoma patients. We hypothesized that stage I and II thymomas would have high cure rates with resection and adjuvant radiation, whereas locally advanced cases would benefit from multimodality therapy. Methods: All patients, diagnosed with thymoma or thymic carcinoma in British Columbia between 1994 and 2009, were identified using the British Columbia Cancer Agency Registry. Chart review was used to collect demographic and treatment data. Detailed pathology review was performed using the World Health Organization classification. Results: One hundred and seventy-one patients were identified for analysis. The 5-year overall survival was 93.3%, 88.7%, 74.6%, 43.4% for stages I, II, III, and IV, respectively. Survival varied significantly among patients with thymoma compared with thymic carcinoma. In patients with stage II disease, adjuvant radiation did not confer an overall survival or recurrence-free survival benefit. Seventy-five patients had locally advanced disease. There was practice variation in treatment of these patients. Patients with thymoma undergoing trimodality treatment had a 5-year median overall survival of 80%, whereas patients with thymic carcinoma had poor outcomes despite aggressive treatment. Conclusions: Survival rates in this population-based series were comparable to those in previously published reports. The ideal management of thymic tumors involves a multidisciplinary approach, particularly in locally advanced disease and selection of patients for adjuvant radiation therapy.

Volumetric Radiosurgery for 1 to 10 Brain Metastases: A Multicenter, Single-Arm, Phase 2 Study

PURPOSE Interest is growing in treating multiple brain metastases with radiosurgery. We report on the effectiveness and tolerability of volumetric radiosurgery (VRS). METHODS AND MATERIALS We enrolled patients with a ≥6-month estimated life expectancy and 1 to 10 brain metastases with a diameter of ≤3 cm at 5 cancer centers. Volumetric radiosurgery was delivered in 5 fractions with 98% target coverage, prescribed as 95% of 50 Gy (47.5 Gy in 5 fractions) to the metastases with no margin and 95% of 40 Gy (38 Gy in 5 fractions) to their 2-mm planning target volumes, concurrent with 20 Gy to the whole brain planning target volume. The treatment was delivered with daily image guidance using conventional linear accelerators and volumetric modulated arc therapy. A magnetic resonance imaging scan was obtained every 3 months. The primary endpoint was the 3-month objective response in the brain according to the Response Evaluation Criteria in Solid Tumors, version 1.1. The principal secondary endpoint was 1-year actuarial control of treated metastases. Toxicities were graded using the Common Terminology Criteria for Adverse Events, version 4.0. The present study is registered with ClinicalTrials.gov (clinicaltrials.gov identifier NCT01046123). RESULTS From July 2010 to May 2013, 60 patients underwent VRS with 47.5 Gy in 5 fractions for 12 metastases in the thalamus and basal ganglia (deep metastases) and 207 non-deep metastases. The median follow-up period was 30.5 months, and the median survival was 10.1 months. For the 43 patients assessable at 3 months, the objective response in the brain was 56%. The treated metastases were controlled in 88% of patients at 1 year and 84% at 3 years. Overall survival did not differ for patients with 4 to 10 versus 1 to 3 metastases (hazard ratio 1.18, P=.6). The crude incidence of severe radionecrosis (grade 3-5) was 25% (3 of 12) per deep metastasis, 1.9% (4 of 219) per non-deep metastasis, and 10% (6 of 60) per patient. CONCLUSIONS For non-deep brain metastases, 47.5 Gy in 5 fractions was tolerable. Volumetric radiosurgery was effective for long-term control of treated brain metastases.

Information for decision making by post-menopausal women with hormone receptor positive early-stage breast cancer considering adjuvant endocrine therapy

PURPOSE To identify the information that post-menopausal women with hormone-receptor positive, early-stage breast cancer want, to help them decide among six treatment options for adjuvant-endocrine therapy. METHODS We surveyed women with early-stage breast cancer who were eligible for adjuvant endocrine-therapy 3-18 months earlier. Participants rated the importance of getting each of 95 questions answered before this decision is made (options: essential/desired/not important/avoid). For questions rated essential or desired, participants identified the purpose(s) for having the question answered: to help them understand, make the decision, plan, or other. Participants indicated the role they played in their actual decision and the role they would prefer if the decision was made today. They also indicated whether they felt they had had a choice of endocrine therapy treatments. RESULTS 188 of 343 questionnaires were returned (response rate 55%). Mean age was 67 yr (range 38-88 yr); 76% were married, and 39% had secondary school education or less. On average, respondents rated 18 questions (range 0-94) essential for decision making. Each question was rated essential for decision making by ≥ 7% of participants but only 1 question by >50%. Regarding roles, 89% of respondents had participated in their actual decision and would want to again; an additional 9% had not participated in their actual decision but would want to at the time of the survey. The percentage of respondents who felt they had no choice of endocrine therapy treatments varied between centres, 25% vs 41% and 49%. CONCLUSIONS Most patients want to participate in the decision but they vary widely in the amount and which specific details they want to help them make the decision. IMPLICATION The wide variation in questions considered important means the support should be tailored to the needs of the individual patient.

A Patient-centered Approach to Evaluate the Information Needs of Women With Ductal Carcinoma In Situ.

Objective: To evaluate the information needs of ductal carcinoma in situ (DCIS) patients. Methods: Four focus groups involving 24 previously treated DCIS patients were conducted to develop a comprehensive list of questions they felt were important to have answered at the time of diagnosis. Using a survey, a separate group of patients treated for DCIS then rated the importance of having each of these questions addressed before treatment decision making. Response options were “essential,” “desired,” “not important,” “no opinion,” and “avoid.” For each essential/desired question, respondents specified how addressing it would help them: “understand,” “decide,” “plan,” “not sure,” or “other.” Results: Focus group participants generated 117 questions used in the survey. Fifty-seven patients completed the survey (55% response rate). Respondents rated a median of 66 questions as essential. The most commonly cited reason for rating a question essential was to “understand,” followed by to “decide.” The top questions women deemed essential to help them understand were disease specific, whereas the top questions deemed essential to help women decide were predominantly treatment specific, pertaining to available options, recurrence and survival outcomes, and timelines to decide and start treatment. Conclusions: DCIS patients want a large number of questions answered, mostly for understanding, and also for deciding and planning. A core set of questions that most patients consider essential for decision making has been formulated and may be used in the clinical setting and in research to develop educational resources and decision-making tools specific to DCIS.

Population-based phase II trial of stereotactic ablative radiotherapy (SABR) for up to 5 oligometastases: SABR-5

BackgroundOligometastases refer to a state of disease where cancer has spread beyond the primary site, but is not yet widely metastatic, often defined as 1–3 or 1–5 metastases in number. Stereotactic ablative radiotherapy (SABR) is an emerging radiotherapy technique to treat oligometastases that require further prospective population-based toxicity estimates.MethodsThis is a non-randomized phase II trial where all participants will receive experimental SABR treatment to all sites of newly diagnosed or progressing oligometastatic disease. We will accrue 200 patients to assess toxicity associated with this experimental treatment. The study was powered to give a 95% confidence on the risk of late grade 4 toxicity, anticipating a < 5% rate of grade 4 toxicity.DiscussionSABR treatment of oligometastases is occurring off-trial at a high rate, without sufficient evidence of its efficacy or toxicity. This trial will provide necessary toxicity data in a population-based cohort, using standardized doses and organ at risk constraints, while we await data on efficacy from randomized phase III trials.Trial RegistrationRegistered through clinicaltrials.gov NCT02933242 on October 14, 2016 prospectively before patient accrual.

122: The Impact of a Central Nervous System Event on Cognitive Function After Radiation Treatment in Patients With One-Ten Brain Metastases

CARO 2016 _________________________________________________________________________________________________________ 122 THE IMPACT OF A CENTRAL NERVOUS SYSTEM EVENT ON COGNITIVE FUNCTION AFTER RADIATION TREATMENT IN PATIENTS WITH ONE-TEN BRAIN METASTASES Laura Beaton, Roy Ma, Fred Hsu, Lovedeep Gondara, Hannah Carolan, Robert Olson, Devin Schellenberg, Francois Germain, Arthur Cheung, Michael McKenzie, Alan Nichol University of British Columbia, Vancouver, BC

Poster — Thur Eve — 57: Craniospinal irradiation with jagged‐junction IMRT approach without beam edge matching for field junctions

PURPOSE Craniospinal irradiation were traditionally treated the central nervous system using two or three adjacent field sets. A intensity-modulated radiotherapy (IMRT) plan (Jagged-Junction IMRT) which overcomes problems associated with field junctions and beam edge matching, improves planning and treatment setup efficiencies with homogenous target dose distribution was developed. METHODS AND MATERIALS Jagged-Junction IMRT was retrospectively planned on three patients with prescription of 36 Gy in 20 fractions and compared to conventional treatment plans. Planning target volume (PTV) included the whole brain and spinal canal to the S3 vertebral level. The plan employed three field sets, each with a unique isocentre. One field set with seven fields treated the cranium. Two field sets treated the spine, each set using three fields. Fields from adjacent sets were overlapped and the optimization process smoothly integrated the dose inside the overlapped junction. RESULTS For the Jagged-Junction IMRT plans vs conventional technique, average homogeneity index equaled 0.08±0.01 vs 0.12±0.02, and conformity number equaled 0.79±0.01 vs 0.47±0.12. The 95% isodose surface covered (99.5±0.3)% of the PTV vs (98.1±2.0)%. Both Jagged-Junction IMRT plans and the conventional plans had good sparing of the organs at risk. CONCLUSIONS Jagged-Junction IMRT planning provided good dose homogeneity and conformity to the target while maintaining a low dose to the organs at risk. Jagged-Junction IMRT optimization smoothly distributed dose in the junction between field sets. Since there was no beam matching, this treatment technique is less likely to produce hot or cold spots at the junction in contrast to conventional techniques.

Thymoma: A population-based study of the management and outcomes for the province of British Columbia.

7023 Background: The optimal approach to the management of thymoma and thymic carcinomas is unclear, particularly for advanced stage disease. Our primary study aim was to analyze treatment practices and outcomes in a population-based cohort of thymoma patients. METHODS All patients (pts) with a pathological diagnosis of thymoma or thymic carcinoma and referred to the British Columbia Cancer Agency (BCCA) between 1994 and 2009 were reviewed. Kaplan-Meier curves and Cox proportional hazard models were used to correlate histology, stage, and treatment with outcomes. Pathology review using WHO classification is currently underway. RESULTS 190 pts were identified of which 171 (90%) were referred to BCCA and eligible for analyses. Median was 60 years; 50% of pts were male. 26% had paraneoplastic phenomena; including 21% with myasthenia gravis.Pts with thymic carcinoma (n=23) and thymoma (n=148) had 5-year overall survival (OS) rates of 38% and 81%, respectively. Survival by stage is detailed in the table. Pts with stage I disease were treated primarily with surgery. Selected stage II pts received adjuvant radiation therapy, which conferred a significant improvement in progression free survival (98 vs. 62 months, p<0.01), but no OS benefit. There were practice variations in management of pts with advanced stage disease (n=71). A multimodality approach that included surgery, radiation, and chemotherapy correlated with better outcomes. Tri-modality treatment for thymoma achieved a 5-year OS of 85%; however, pts with advanced thymic carcinoma had poor outcomes despite aggressive treatment. In multivariate analyses histology (thymoma vs. thymic carcinoma) and surgery were significant predictors of OS. CONCLUSIONS This study is the first population-based series to detail treatment and outcomes for thymoma. Outcomes compare favorably to series from single institutions. Pts with locally advanced disease for whom initial surgical resectibility is uncertain should be triaged to a multidisciplinary team for consideration of multimodality treatment. [Table: see text].