Frameless single robotic radiosurgery of pulmonary metastases in colorectal cancer patients.

Abstract

e15147 Background: Metastases due to colorectal cancer are a rising problem, since modern therapy allows for long term survival. Surgical intervention and radiation therapy are the most common approaches for pulmonary metastasectomy. Well established in liver metastasectomy, the role of minimal invasive techniques in pulmonary metastases remains unclear. Frameless single robotic radiosurgery (Cyberknife) of pulmonary metastases in colorectal cancer pts offers high precision radiation therapy. Methods: We analyzed 34 pts and a total of 45 lesions receiving Cyberknife treatment of lung metastases in colorectal cancer pts. We analyze the safety and efficacy of Cyberknife therapy of pulmonary metastases in patients suffering from colorectal cancer. Primary endpoint was local control (LC); secondary endpoints were progression-free survival (PFS), overall survival (OS) and distant control (DC). Results: In 4/45 cases fiducial placement lead to a pneumothorax; 3/4 pts needed chest tube insertion afterwards. No radiation-associated side effects were reported in 57.8% of pts. In 10/45 cases (22.2%) pts. suffered from acute radiation-associated side effects. 7/45 cases (15.6%) reported a late-onset of radiation-associated side effects. According to the toxicity criteria RTOG/EORTC maximal radiation-associated side effects reached Grade 1. 35/45 treated lesions (77.8%) decreased in size or remained unchanged (CR, PR, SD), 8/45 (17.8%) lesions increased in size (PD) and 2/45 (4.4%) lesions were not evaluable due to missing follow-up scans. Local progression within the previously irradiated lesion was shown in 2 lesions (4.4 %). Median PFS, calculated with Kaplan-Meier method, was 6.0 months. Within a median follow-up time of 19.4 months, medium OS was 19.9 months ranging from 3.0 months to 61.0 months. Distant recurrence outside the irradiated lung was observed in 21/34 pts, representing 61.8 % of all pts. Intrapulmonal progression in previously not-irradiated sections occurred in six pts. Conclusions: Cyberknife treatment of pulmonary metastases is safe and well tolerated. In mCRC patients with pulmonary metastases, who are not eligible for surgery, Cyberknife radiation offers a valuable treatment option.