RESUMEN
PURPOSE: To report the local control, survival, and low toxicity observed at the Cooper University Hospital CyberKnife Center post stereotactic body radiation therapy (SBRT) in the treatment of lung tumors near the mediastinum. METHODS AND MATERIALS: Twenty-four medically inoperable lung cancer patients with tumors near the mediastinum were treated using the Accuray CyberKnife system (Accuray, Sunnyvale, CA) with Monte Carlo dose calculations and heterogeneity corrections from July 2008 to May 2010. The prescription dose ranged from 28.5 Gy to 60 Gy in 3-5 fractions. For conventional fractionation schemes, Emami et al(1) organized the dose tolerance limits into a unified format for clinical utility and partitioned them into 2 risk levels (5% and 50%) with preset volumes for most critical structures throughout the body. In contrast, statistical SBRT dose tolerance limits for mediastinal structures have not been established yet. We have sufficient experience at least to begin organizing a unified format with low-risk and high-risk partitions and preset volumes for 1-5 fractions exposing mediastinal structures. With the help of the (dose-volume histogram) DVH Evaluator, a software tool developed by our senior author, each treatment plan was assessed for safety and feasibility prior to treatment. The DVH Evaluator was also used to analyze the follow-up data and to create graphs of risk, called DVH Risk Maps, superimposing clinical data onto the unified SBRT dose tolerance limits. RESULTS: It was not feasible to prescribe the doses of peripheral lung lesions for all tumors near the mediastinum because of known toxicity. The crude local tumor control rate achieved in our series was 92%. Median survival was 26.8 months for the primary lung cases and 9.6 months for the metastatic cases. No patients experienced grade 3 or higher toxicities. CONCLUSIONS: We affirm that SBRT is feasible in the treatment of centrally located lung cancers when the dose tolerance limits of critical structures are diligently respected. The low adverse event rates that we have experienced, combined with a good local tumor control rate, are encouraging.
RESUMEN
Leptomeningeal disease (LMD) can occur in a small percentage of patients with active metastatic cancer. However, we report a case of LMD occurring during disease remission in a patient with carcinoma of unknown primary with panreaticobiliary features. A 45-year-old woman was found with mediastinal and abdominal lymphadenopathy with lymph node biopsy consistent with adenocarcinoma, expressing immunomarkers CK7, CK20, and Ca19-9 along with markedly elevated serum Ca19-9 level. The patient was started on a pancreatic cancer directed chemotherapy regimen of Folfirinox (5-fluorouracil, leucovorin, oxaliplatin, irinotecan) and achieved complete response. She was then noted to have slowly rising Ca19-9 level that did not correlate with her lack of evidence of systemic disease progression. Eventually, she presented with neurologic symptoms and was found on imaging to have isolated LMD.