An observational retrospective analysis of the main metastatic site and corresponding locoregional treatment as a prognostic factor in metastatic gastric cancer.

Despite novel drugs, the prognosis for patients with metastatic gastric cancer remains poor. In rare instances, locoregional therapies are used in addition to standard chemotherapy in patients with oligometastatic involvement. This type of approach has not been supported by solid published evidence. The aim of the present retrospective study was to assess the prognostic impact of factors such as metastatic site, tumour histology and locoregional treatment in patients with metastatic gastric cancer. A total of 184 patients with metastatic gastric or gastroesophageal junction adenocarcinoma who received at least one line of palliative therapy with doublet or triplet chemotherapy were enrolled in the current analysis. Median overall survival (OS) was 8.32 months (95% CI, 7.02-9.41) and median progression-free survival (PFS) was 4.16 months (95% CI, 3.24-5.08). Lung metastases vs. other sites of metastatic involvement [hazard ratio (HR), 0.27; P=0.0133] and intestinal histology (HR, 0.48; P=0.08) were significantly associated with an improved OS. Improved PFS was also observed (HR, 0.49; P=0.10 and HR, 0.72; P=0.08 for lung metastases and intestinal histology, respectively). Second line chemotherapy and locoregional treatment of metastases (surgery or radiotherapy) were associated with improved OS (HR, 0.52; P<0.0001 and HR, 0.35; P<0.0001, respectively). Multivariate analysis confirmed an independent prognostic role for OS only for locoregional treatment, second line treatment and intestinal histology. The present results suggested that the presence of lung metastases alone was not a relevant prognostic factor and was influenced by the availability of further lines of treatment or by locoregional treatments. Locoregional treatments in patients with oligometastatic disease should be offered as they allow prolonged survival in patients with otherwise relatively short life expectancy.