PURPOSE: To report local control and survival of robotic radiosurgery for the treatment of hilar lung tumors.
METHODS: Patients presenting with inoperable primary and metastatic hilar lung tumors, treated using robotic radiosurgery, were retrospectively reviewed for local control and survival. Hilar location was defined as abutting or invading a main stem bronchus. Fiducial markers were implanted by conventional bronchoscopy within or adjacent to tumors to serve as targeting references. A prescribed dose of 30 to 40 Gy to the gross tumor volume (GTV) was delivered in 5 fractions. Clinical examination and PET/CT imaging were performed at 3 to 6-month follow-up intervals.
RESULTS: Twenty-four patients were accrued over a 54 month period. Four had inoperable primary lung tumors and 20 had hilar lung metastases. The median GTV was 91 cc (range, 23 - 324 cc) which received a median dose of 35 Gy (range, 30 - 40 Gy) over 4 - 7 days (median, 5 days). The resulting mean maximum point doses delivered to the esophagus and mainstem bronchus were 27 Gy (range, 11 - 40 Gy) and 45 Gy (range, 30 - 50 Gy), respectively. At a median follow-up of 12 months, the 1-year Kaplan-Meier local control and overall survival estimates were 71 % and 61 %, respectively. The majority of deaths were attributed to metastatic disease. However, 1 death was attributed to local recurrence and one death was attributed to mainstem bronchus fistula in a patient with gross mainstem endobronchial tumor.
CONCLUSION: Robotic radiosurgery is a palliative treatment option for hilar lung tumors, but local control and survival remain poor at one year. Prospective dose escalation studies excluding patients with gross mainstem endobronchial tumor are planned.
CLINICAL IMPLICATIONS: Robotic radiosurgery is a novel palliative treatment option forhilar lung tumors. Additional research is required to improve local control.
DISCLOSURE: Keith Unger, No Financial Disclosure Information; No Product/Research Disclosure Information