A systematic review and meta-analysis of stereotactic body radiation therapy for colorectal pulmonary metastases

Abstract

Background: There is growing evidence to support the hypothesis that radical treatment of pulmonary oligometastatic disease with stereotactic body radiation therapy (SBRT) can improve oncological outcomes. However, some reports suggest colorectal cancer (CRC) pulmonary metastases are associated with radioresistance. The present systematic review aimed to assess the local control (LC), overall survival (OS), and progression-free survival (PFS) of patients with CRC pulmonary metastases treated by SBRT. Secondary outcomes included assessment of peri-procedural complications and identification of prognostic factors on LC. Methods: Electronic databases were systematically searched from their dates of inception using predefined criteria. Summative statistical analysis was performed for patients with CRC pulmonary metastases, and comparative meta-analysis was performed for patients with CRC versus non-CRC pulmonary metastases. Results: Using predefined criteria, 18 relevant studies were identified from the existing literature. LC for CRC pulmonary metastases treated by SBRT at 1-, 2-, and 3-year were estimated to be 81%, 66%, and 60%, respectively. OS and PFS at 3-year were 52% and 13%, respectively. Patients with CRC pulmonary metastases were associated with significantly lower LC compared to non-CRC pulmonary metastases [HR, 2.93; 95% confidence interval (CI), 1.93-4.45; P<0.00001], but higher OS (HR, 0.61; 95% CI, 0.45-0.82; P=0.001). There were no reported periprocedural mortalities and low incidences of periprocedural morbidities. Conclusions: These findings may have implications for patient and treatment selection, dose fractionation, and support the hypothesis that CRC pulmonary metastases may require higher biological effective doses while respecting normal tissue constraints when treated with SBRT.

Tumor Control and Overall Survival after Stereotactic Body Radiotherapy for Pulmonary Oligometastases from Colorectal Cancer: a Meta-Analysis

“…One of them presented pooled estimates as the odds ratio of local failure [ 39 ]. The other meta-analysis reported the LC, OS, and progression-free survival rates after SBRT for POM-CRC [ 15 ]. Compared to information provided by the previous studies, our meta-analysis has an additional strength.…”

“…The NCCN and ESMO groups also recommend SBRT as an alternative treatment modality for OM patients who are incapable of undergoing surgery. To present the effects of SBRT for POM-CRC, several studies with various publication types including original study, systematic review, and meta-analysis have been published [ 14 , 15 ]. Although previous studies have shown excellent tumor control ability of SBRT, physicians still do not have a clear reason to choose SBRT over surgery for POM-CRC patients.…”

Role of Thermal Ablation in Colorectal Cancer Lung Metastases

“…Surgical lung metastasectomy obtains a R0 resection roughly 90% of the time [ 28 ]. SABR has been reported in a recent meta-analysis with LC rates at 1, 2 and 3 years estimated to be 81%, 66% and 60% [ 29 ], but the LC rate was significantly lower for colorectal cancer lung metastases compared to non-colorectal cancer lung metastases (HR, 2.93; 95% confidence interval, 1.93–4.45; p < 0.000001).…”

“…The OS of patients treated with RFA seems comparable to what was reported in recent reports of surgical resection, with an overall survival at 5 years ranging from 32 to 65% [ 33 , 34 , 35 ] and a median overall survival of 35 to 70 months. As of today, SABR seems to provide lower OS, of around 52% at 3 years in a large meta-analysis [ 29 ].…”

“…The toxicity profile of SABR is also acceptable, with no peri-procedural mortality. The most common and serious respiratory adverse event (grade 3 CTCAE) is pneumonitis, which affects 3 to 5% of patients in the literature [ 29 ]. It is noteworthy that a decrease in lung function after SABR is delayed.…”