Kowalchik, Kristin

125 Background: Treatment for locally advanced esophageal carcinoma is radiation and chemotherapy, with or without surgery. Radiation has traditionally been delivered with 3D conformal radiation therapy (3D CRT). This study evaluates late toxicity in patients treated with IMRT as well as early outcomes and acute toxicity. Methods: This is a retrospective review of 32 patients with esophageal carcinoma treated with IMRT at Mayo Clinic Florida from 2008 -2012. Pathology includes squamous cell and adenocarcinomas. Tumor sites include middle and lower thoracic and GE junction. Clinical stages are TX-T3, N0-3, M0-1. All patients received at least one cycle of concurrent chemotherapy. IMRT dose was 50.4 Gy in 28 fractions prescribed to a target volume including the tumor and regional lymphatics. IMRT plans utilized coplaner beams in a 7-9 beam arrangement or volumetric modulated arc therapy. Results: Median follow-up is 8.9 months (range 2.4-23.0) for all patients and 13.1 months (range 2.8-23.0 months) in surviving patients. Median patient age is 69 (range 46-87). Trimodality treatment was completed in 20 patients (62.5%). Surgery was either an open or minimally invasive esophagogastrectomy. The incidence of grade 3 or greater late toxicity at 1 year was 48% in surgery patients and 26% in non-surgery patients. The most common grade 3 or higher toxicity was esophageal strictures in 25%. The incidence of any grade 3 or greater acute toxicity was 65% in the surgery patients and 75% in the non-surgery patients. Overall survival (OS) for all patients at 18 months is 57% (CI 37-86%) and progression-free survival (PFS) is 60% (36-99%). OS and PFS for trimodality therapy at 12 months is 83% (66-100%) and 81% (63-100%) respectively and for bimodality therapy is 34% (12-93%) and 70% (33-100%) respectively. Conclusions: Increased late toxicity occurs in surgery patients, and increased acute toxicity in non-surgery patients. Lower survival in non-surgery patients may be due to early progression, morbidities which preclude surgery or improved survival with surgery. Overall, IMRT is a feasible treatment modality, which may be equally efficacious to 3D CRT for the treatment of esophageal carcinoma.

211 Background: The current standard of care for locally advanced esophageal cancer includes chemoradiotherapy with or without surgery. Radiation is usually delivered via a 3D technique. IMRT has been utilized in the treatment of multiple tumors and demonstrated similar efficacy while offering the possibility of decreased toxicity. Methods: Thirty-six patients were treated with IMRT and chemotherapy. Twenty-one patients underwent surgical resection. Eleven underwent open surgery and the remainder underwent minimally invasive surgery. Chemotherapy consisted primarily of 5-FU with oxaliplatin or cisplatin. All but two patients received 50.4 Gy; one patient received 41.4 Gy without surgery and one patient discontinued treatment after 25.2 Gy. Eleven patients required a treatment break during radiotherapy. The median age was 69 (range 46-87). Approximately two-thirds of tumors were adenocarcinomas located in the lower thorax. Two thirds of patients were staged as T3 and had positive lymph nodes. The median tumor size was 5 cm (range 2-13). Results: With a median follow-up of 21.3 months (range 2.4-44.8) and 33.9 months for survivors (range 3.7-44.8), overall survival at 24 months was 55%. The 24 month overall survival was 75% vs 24% for surgical and non-surgical patients, respectively. Seven patients had a complete pathologic response. Twenty-four patients experienced grade 3 or higher acute toxicity and there was one grade 5 toxicity. Acute toxicity was similar between surgery and non-surgery patients. Fourteen patients experienced grade 3 or higher late toxicity; 9 surgery and 5 non-surgery patients. The most frequent late toxicity was grade 3 stricture (21%). On multivariate analysis, advanced age (RR [10 year increase] 2.01, p=0.032) and heart maximum dose >55 Gy (RR 3.73, p=0.011) were associated with decreased survival. Conclusions: Patients who undergo surgery after chemoradiotherapy demonstrate improved survival; however, this may be related to underlying comorbidities that preclude surgery. IMRT appears to be a reasonable treatment option that may reduce complications from radiotherapy. Careful attention should be given to heart dose during treatment planning.

284 Background: Frameless stereotactic radiosurgery (SRS) is single fraction radiation therapy delivered to an intracranial lesion. Rather than with a rigid head frame, frameless SRS uses a thermoplastic mask for immobilization. The benefit of this mask includes the ability to simulate and treat the patient at different times, ease of patient set-up and improved patient comfort. Clinically, frameless SRS is used for primary brain tumors and metastatic lesions. The length of the treatments may vary based on a number of factors, including total treatment dose, number of monitor units, number and arrangement of beams, and equipment manipulations. This is a single institution review of patients treated with SRS with positional checks made before, during and at the completion of treatment to evaluate intrafraction motion. Methods: Patients were treated with SRS at Mayo Clinic Florida between 2010 and 2011. All patients were immobilized with a thermoplastic mask and treated on a Varian IX Clinac. KV Cone beam CT was taken prior to the initiation of treatment to verify the treatment position. Cone beam CT’s were also performed at the midpoint and conclusion of treatment. The same physician analyzed all cone beam CT’s. Adjustments were recorded in each dimension and analyzed to determine intrafraction motion. Results: Intrafraction motion was evaluated during six separate SRS cases. The mean displacements at mid-treatment were 0.67±0.52 mm, 0.50±0.55 mm, 0.83±0.75 mm, and 1.35±0.78 mm in the medial/lateral, superior/inferior, anterior/posterior, and vectoral direction, respectively. The mean post-treatment displacements were 0.17±0.41 mm, 0.67±0.82 mm, 0.50±0.84 mm, and 1.11±0.96 mm in the medial/lateral, superior/inferior, anterior/posterior, and vectoral direction, respectively. Estimated overall margins to accommodate intrafraction motion in 90% of patients were 2.63 mm and 2.69 mm at mid-treatment and post-treatment, respectively. Conclusions: The majority of intrafraction motion occurred during the first portion of treatment. Intrafraction motion during the course of frameless SRS treatment is not negligible and approximately a 2.5 mm margin should be taken into account during the planning process.

Purpose. Women with ductal carcinomain situ(DCIS) are often candidates for breast-conserving therapy, and one option for radiation treatment is partial breast irradiation (PBI). This study evaluates the use of preoperative breast magnetic resonance imaging (MRI) for PBI selection in DCIS patients.Methods. Between 2002 and 2009, 136 women with newly diagnosed DCIS underwent a preoperative bilateral breast MRI at Mayo Clinic in Florida. One hundred seventeen women were deemed eligible for PBI by the NSABP B-39 (National Surgical Adjuvant Breast and Bowel Project, Protocol B-39) inclusion criteria using physical examination, mammogram, and/or ultrasound. MRIs were reviewed for their impact on patient eligibility, and findings were pathologically confirmed.Results. Of the 117 patients, 23 (20%) were found ineligible because of pathologically proven MRI findings. MRI detected additional ipsilateral breast cancer in 21 (18%) patients. Of these women, 15 (13%) had more extensive disease than originally noted before MRI, and 6 (5%) had multicentric disease in the ipsilateral breast. In addition, contralateral breast cancer was detected in 4 (4%).Conclusions. Preoperative breast MRI altered the PBI recommendations for 20% of women. Bilateral breast MRI should be an integral part of the preoperative evaluation of all patients with DCIS being considered for PBI.