Stereotactic body radiotherapy for colorectal lung oligometastases: preliminary single-institution results

Purpose: To present the preliminary results of stereotactic body radiotherapy (SBRT) for lung oligometastases originated from colorectal cancer (CRC). Methods: Thirteen patients (9 male, 4 female) with lung oligometastases from CRC were prospectively selected for SBRT between July 2009 and July 2013. We used a dose risk-adapted schedule of radiation. Results: The median follow-up was 9.16 months (range 2-45.6). The median age was 69 years (range 40-84). Three cases (23.1%) were treated with 12.5 Gy in 4 fractions (112.5 biological effective dose/BED). Four cases (30.8%) received 18Gy (151.2 BED), 2 (15.4%) 7.5 Gy in 8 fractions (BED 105) and 4 (30.8%) a monofraction of 34 Gy (149.6 BED). There were 5 (38.5%) complete responses, 5 (38.5%) partial responses and 3 (23%) patients remained with stable disease. During follow-up 6 patients (46.2%) showed distant metastases: liver (N=3, 50%), bone (N=1, 16.6%) and contralateral lung (N=2, 33.3%). Median time to systemic progression was 9 months. One- and two-year distant progression-free survival (DPFS) was 45.8% and 22.9%, respectively. Local control (LC), overall survival (OS), and cause-specific survival (CSS) at one- and two-years were all 92.3%. A tendency for a better local response and DFPS in patients aged s70 years and BED > 120 Gy was observed. No grade 3-4 toxicity was noticed. Conclusions: Excellent LC and longer DFS could be achieved with SBRT in oligometastatic lung disease from CRC, delaying thus disease progression and the need for further treatment.