Abstract
BackgroundTo assess the safety and efficacy of Stereotactic Ablative Radiotherapy (SABR) in oligometastatic patients from colorectal cancer.Methods82 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.ResultsMedian 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.ConclusionsSABR is a safe and feasible alternative treatment of oligometastatic colorectal liver and lung metastases in patients not amenable to surgery or other ablative treatments.
Highlights
To assess the safety and efficacy of Stereotactic Ablative Radiotherapy (SABR) in oligometastatic patients from colorectal cancer
A contrast-free computed tomography (CT) scan were acquired for all patient and the 3 phases contrast-enhanced CT were acquired for patient with hepatic metastases
The 4-dimensional CT (4D-CT) imaging was performed in all patients with lung metastases and in 11 patients (30.5%) with hepatic metastases because a respiratory excursion was greater of 5 mm
Summary
To assess the safety and efficacy of Stereotactic Ablative Radiotherapy (SABR) in oligometastatic patients from colorectal cancer. The concept of “oligometastatic disease” was introduced to identify a condition in which the number and sites of metastases are limited from one to five [1]. According to this hypothesis of orderly progression, this is an intermediate state before widespread dissemination. Studies suggested that oligometastases can represent only the clinically detectable lesions in the context of widespread occult disease and their treatment may not affect survival [2]. Both hypothesis are correct [3]. Given the improvements in diagnostic imaging, the prevalence of oligometastatic state is increasing [4]
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