Faculty Bibliography

Purpose: To determine optimal (prone vs. supine) treatment positions for breast radiotherapy by classifying geometric features extracted from prone CT scans. Method and Materials: CT scans from patients enrolled in NYU 05‐181 Protocol were studied to discern predicting factors for optimizing treatment positions for breast radiotherapy. Each of the 400 patients accrued for this protocol underwent CT simulation and planning in both supine and prone positions. The treatment set up was chosen based on maximum sparing of heart and lung. Since the results demonstrated that most patients were best treated prone, we studied whether a support vector machine (SVM) classifier could successfully predict optimal position based on a single prone CT scan and limit a second supine CT only to the minority of women best treated supine. To build this classifier, prone CT scans of NYU 05‐181 were de‐identified and exported in DICOM RT format. Three‐dimensional shape and distance features were computed from organs at risk and the planning target volume in the CT scans. We used a k‐fold cross validation procedure to test the performance of the SVM classifier. Results: Images of 36 patients (23 prone‐treated and 13 supine‐treated) were used. Preliminary results indicate that breast volume, heart and lung involvement in the treatment field are significant predicting factors. A weighting of 1:5 (prone‐treated: supine‐treated) was used when determining the soft margin hyper plane of the SVM classifier. The purpose is to increase the specificity [true‐supine/ (true‐supine+false‐prone)] of the classifier since patients classified as prone will not receive a validation supine CT scan. A sensitivity [true‐prone/(true‐prone+false‐supine)] of 87% and a specificity of 92% was achieved using 11 geometric features and the SVM classifier. Conclusion: Preliminary data support the use of a feature‐based classification to predict the optimal treatment position from prone CT scans

BACKGROUND: We report the results of a prospective trial investigating the use of accelerated, hypofractionated whole-breast radiation therapy after breast-conservation surgery for ductal carcinoma in situ (DCIS). PATIENTS AND METHODS: A total of 59 patients with a median age of 54 years (range, 36-78 years) completed a phase I/II study of hypofractionated radiation therapy for treatment of DCIS. Eligibility criteria included patients with mammographically detected DCIS, status after segmental mastectomy with negative margins, and no residual calcifications. All patients were treated with external-beam radiation therapy without a boost, over 3 weeks, to a total dose of 42 Gy to the entire breast (2.8 Gy per fraction in 15 fractions). To optimally spare heart and lung, 34 of the 59 patients (57%) were treated in the prone position. Twenty-nine of 59 patients (49%) received adjuvant hormonal therapy. RESULTS: Overall, radiation therapy was well tolerated, with modest acute toxicity limited to grade 1 radiation dermatitis (76%), breast edema (17%), and fatigue (12%). With a median follow-up of 36 months, late toxicities included grade 1 hyperpigmentation changes (85%), induration (66%), asymmetry (64%), and breast fibrosis (17%), with 3 cases of grade 2 fibrosis and 1 case of grade 2 hyperpigmentation. Among the patients with >or= 3 years of follow-up, cosmesis was scored as good to excellent in 21 patients (91%) and fair in 2 patients (9%). At the time of this report, no ipsilateral or contralateral breast recurrences have occurred. CONCLUSION: These data demonstrate the feasibility of treating the whole breast for DCIS with a hypofractionated regimen, with modest acute and late toxicity

PURPOSE: A small fraction of patients with 1-2 brain metastases will not be suitable candidates to either surgical resection or stereotactic radiosurgery (SRS) due to either their location or their size. The objective of this study was to determine the local control, survival, patterns of relapse and the incidence of brain injury following a course of hypofractionated stereotactic radiotherapy while avoiding upfront whole brain radiation therapy (WBRT) in this subgroup of patients. METHODS: A Gill-Thomas removable head frame system was used for immobilization. Brain LAB software with dynamic multileaf collimator hardware was used to design and deliver an intensity-modulated radiation therapy treatment plan. A dose of 600 cGy was prescribed to the 100% isodose line that would encompass the lesion with a 3-mm margin. A total dose of 3,000 cGy was delivered in 5 fractions using 2 fractions per week. The patients were followed with neurological examination and serial MRI images done every 3 months following the procedure. RESULTS: Twenty patients have been treated using this fractionation schedule since April 2004. The 1-year local control at the site of original disease is 70%. The complete response, partial response and stable disease at the last follow-up were 15, 30 and 45%, respectively. Two patients had local recurrence at the site of original disease, while 5 had evidence of leptomeningeal disease. Two additional patients developed new brain metastases, resulting in a 1-year brain relapse-free survival of 36% following this approach. The median overall survival was 8.5 months. Three patients (15%) developed steroid dependency lasting 3 months or longer following the procedure. Four patients (20%) needed WBRT as salvage following this approach. CONCLUSIONS: The preliminary results of hypofractionated SRS are comparable to both surgery and SRS data for solitary brain metastases in terms of local control and overall survival with acceptable morbidity in this cohort of unfavorable patients