According to an accepted manuscript published in the American Journal of Roentgenology (AJR), upfront ablation plus adjuvant systemic therapy improves progression-free survival (PFS) of patients with colorectal liver oligometastases (CLOM) and low tumor burden score (TBS), supporting ablation as an alternative to surgical resection. 

Clarifying that upfront thermal ablation performed two to four weeks before starting systemic therapy achieved significantly better PFS, compared with thermal ablation delayed two to three months after the star of therapy, “the findings will help guide the optimal clinical implementation of thermal ablation for patients with CLOM who are not candidates for surgical resection,” writes corresponding author Ping Liang, MD, PhD, from the department of interventional ultrasound at Fifth Medical Center of Chinese PLA General Hospital in Beijing.

Of 543 total patients (346 men, 197 women; mean age, 58.1 years) with CLOM across nine institutions, 322 patients delayed thermal ablation, whereas 118 underwent thermal ablation upfront—in combination with systemic therapy—between October 2009 and December 2020. Analyses included all patients using crude data, as well a patient subset using propensity-score matching (PSM) for balanced baseline variables. 

Based on number and size of liver metastases, patients were then classified as having a low or high TBS. PFS was the primary outcome; secondary outcomes included overall survival. Ultimately, in this multicenter retrospective study of patients with CLOM, after application of PSM, median PFS was 1.1 years and two years in patients who underwent delayed and upfront ablation, respectively, in combination with systemic therapy.

“In subgroup analysis,” the authors of the AJR accepted manuscript add, “the difference between the two timings for thermal ablation was observed in patients with low TBS, but not in patients with high TBS.”