Stereotactic Ablative Radiotherapy (SABR) in inoperable oligometastatic disease from colorectal cancer: a safe and effective approach
1 Radiotherapy and Radiosurgery Department, Humanitas Clinical and Research Center, Rozzano, MI, Italy
2 Medical Physics Unit, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland
3 Medical oncology and hematology unit, Humanitas Clinical and Research Center, Rozzano, MI, Italy
BMC Cancer 2014, 14:619 doi:10.1186/1471-2407-14-619Published: 27 August 2014
To assess the safety and efficacy of Stereotactic Ablative Radiotherapy (SABR) in oligometastatic patients from colorectal cancer.
82 patients with 1–3 inoperable metastases confined to one organ (liver or lung), were treated with SABR for a total of 112 lesions in an observational study. Prescription dose ranged between 48 and 75Gy in 3 or 4 consecutive fractions. Primary end-points were local control (LC), overall survival (OS) and progression-free survival (PFS). Secondary end-point was toxicity.
Median follow-up was 24 months (range 3–47). One, two and three years LC rate was 90%,80% and 75% (85%,75% and 70% for lung and 95%, 90% and 85% for liver metastases; no statistically significance was found). The difference in LC between the subgroup of lesions treated with ≥60 Gy (n = 58) and those irradiated with <60 Gy (n = 52) was statistically significant, with a 1, 2 and 3 yrs LC of 97%,92% and 83% for the higher dose, compared to 85%,70% and 70% for the lower dose (p < 0.04). Median OS was 32 months. Actuarial OS rate at 1, 2 and 3 yrs was 85%,65% and 43%. Univariate analysis showed a correlation only between OS and cumulative GTV > 3 cm (p < 0.02). Median PFS was 14 months, with a PFS rate of 56% at 1 yr and 40% at 2-3 yrs, without correlation with the site and prescription dose (p < 0.48 and p < 0.56). No patients experienced radiation-induced liver disease or grade >3 toxicity.
SABR is a safe and feasible alternative treatment of oligometastatic colorectal liver and lung metastases in patients not amenable to surgery or other ablative treatments.