Neoadjuvant chemotherapy in relation to long-term mortality in individuals cured of gastric adenocarcinoma.

Background: Late effects of chemotherapy could affect mortality amongst cancer survivors. This study aimed to clarify if neoadjuvant chemotherapy for gastric adenocarcinoma influences the long-term survival in individuals cured of this tumour.

Methods: This was a nationwide and population-based cohort study that included all individuals who underwent gastrectomy for gastric adenocarcinoma in Sweden between 2006 and 2015 and survived for ≥ 5 years after surgery. The cohort was followed up until death or end of study period (31 December 2020). Multivariable Cox proportional hazards regression was used to provide hazard ratios (HR) with 95% confidence intervals (CI). The HR were adjusted for age, sex, comorbidity, education, calendar year, tumour sub-location, in-hospital complications, and splenectomy. Data came from medical records and nationwide registers.

Results: Amongst 613 gastric adenocarcinoma survivors, neoadjuvant chemotherapy (used in 269 patients; 43.9%) was associated with a decreased crude mortality rate (HR 0.66, 95% CI 0.46-0.96). However, the association attenuated and became statistically non-significant after adjustment for all confounders (HR 0.83, 95% CI 0.56-1.23) and after adjustments solely for age and comorbidity (HR 0.82, 95% CI 0.56-1.20). Stratified analyses did not reveal any statistically significant associations between neoadjuvant chemotherapy and long-term mortality in categories of age, sex, comorbidity, calendar year and tumour sub-location.

Conclusion: Neoadjuvant chemotherapy did not decrease the long-term survival amongst gastric adenocarcinoma survivors. Patients who received neoadjuvant chemotherapy were a selected group characterised by younger age and fewer severe comorbidities and therefore with better chances of long-term survival.