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The article presents the case study of a 52-year-old woman presented with a six months history of vaginal bleeding. The patient was treated with a combination of concominant radiotherapy and chemotherapy. She also received six cycles of etoposide and cisplatin. The article also discusses the causes and treatment of small cell carcinoma of the endometrium.

Purpose: To re-evaluate planning target volume (PTV) and organ at risk (OAR) dosimetry using Monte Carlo recalculation of treatment plans initially calculated using the Ray-Trace algorithm (effective path length method, EPL). Any differences would be correlated with known clinical outcome in terms of local failure (LF) and toxicity. Methods: Lung CK SBRT treatment plans initially calculated using an EPL algorithm (without correction for tissue inhomogeneity) were re-calculated with MC algorithm. PTV coverage and doses to OARs were compared. We reviewed PTV coverage of patients with LF, volume of the chest wall receiving ≥ 30 Gy (V30) of patients with costal tenderness or rib fracture and percentage total lung volume receiving 5 Gy (V5) and 20 Gy (V20) for patients with grade ≥ 3 pneumonitis. Results: Twenty four plans were recalculated. Median clinical follow-up on these patients was 19 months. Median prescription dose was 60 Gy (range, 48-60 Gy) in 3 fractions (range, 3-5). With EPL and MC respectively, median PTV coverage was 95 % and 91%. Thirteen patients (54%) had a 5% or greater drop in PTV coverage after recalculation (median 9%, range (+6 to -64%). However, in 2 of the 3 cases of LF PTV coverage was actually better than expected (95% PTV coverage for EPL vs. 99% by MC). The chest wall V30 increased by a median of 1.4 cc following re-calculation. Unsurprisingly, the median V30 was greater in the 12 cases of chest wall toxicity (27cc by EPL vs. 28cc by MC) that for the other patients (10 cc using either EPL or MC). Of the patients with chest wall toxicity, 3 had ≥ 5cc (range, 8.4-16cc) V30 increase on MC re-calculation. EPL and MC lung V5 and V20 differences were not significant. Two patients with pulmonary fibrosis developed grade 5 pneumonitis. Whereas median V20 was 5% (EPL and MC) (range, 2-10%) for the other patients, V20 for these 2 patients was19%(MC). Conclusion: MC recalculation predicted worse PTV coverage than EPL, however EPL inaccuracies do not appear to be implicated in LF. No significant differences were found in either chest wall V30, lung V5 or lung V20. Our work confirms that chest wall toxicity correlates with higher V30 and suggested that more severe lung constraints should be used for patients with pulmonary fibrosis. Despite improving the accuracy of patient dosimetry, the clinical benefits of MC dose calculation remain to be demonstrated. Disclosure: No significant relationships. [ABSTRACT FROM AUTHOR]

Introduction: Stereotactic body radiotherapy (SBRT) for inoperable early stage non small cell lung cancer (NSCLC) has been shown to be a safe treatment option with excellent local control. However, higher toxicities have been reported with standard SBRT fractionation for centrally located tumors. The safety and optimal fractionation of SBRT remain under investigation. Purpose: To determine initial local control, survival and toxicity rates in patients with centrally located tumors treated with SBRT at our institution using the Cyberknife® (CK) robotic radiosurgery system. Method: Thirty-nine patients with centrally located early stage NSCLC tumors were treated from 2009 to 2011. Central lesions were defined as tumors within 2 cm of the tracheobronchial tree or adjacent to the mediastinum (as per RTOG 0813 guidelines). Direct soft tissue tracking (Xsight Lung) was used in 20 (51%) patients, fiducials in 10 (26%) and tracking of adjacent vertebral bodies (Xsight Spine) in 9 (23%). Treatment doses were adjusted according to strict dose constraints to organs at risk. One patient received 48Gy in 4 fractions, 30 (77%) received 50Gy in 4-5 fractions and 8 (21%) received 60Gy in 3 fractions. Kaplan Meier curves were used for estimation of local control, overall survival and disease-specific survival. Toxicity data were graded as per the Common Terminology Criteria for Adverse Events version 3.0. Results: The median follow-up was 16 months (range, 9-35). Median age was 78 (range, 62-93). With a median tumor size of 3.2 cm (r= 2-5 cm), 24 patients (62%) were staged T1N0M0 and 15 patients (38%) had a stage T2aN0M0. Twenty-one (54%) tumors were adjacent to the mediastinum and 18 (46%) were within 2 cm of the tracheobronchial tree. At a median follow-up of 16 months, actuarial local control was 90%. The 4 patients with local recurrences received 48-50 Gy in 4-5 fractions (median biological equivalent dose of 105 Gy vs 180 Gy for patients without failure, α/β = 10). Estimated actuarial overall survival and disease-specific survival at 2 years were 75% and 79%, respectively. Three patients experienced grade 2 rib tenderness. There was no grade ≥ 3 toxicity. Conclusion: In our initial experience we have seen minimal toxicity with CK SBRT for centrally located lung tumors. Doses ≤ 50 Gy in 4-5 fractions (biological equivalent dose of 105 Gy) might be associated with higher local failure rates. Disclosure: No significant relationships. [ABSTRACT FROM AUTHOR]