Multicenter retrospective cohort study of patients with locally advanced gastric and esophagogastric junction cancer, who achieved pathological complete response: incidence, patterns and predictors of disease progression (report 3)

Abstract

Background. Pathological complete response (pCR, ypT0N0) after neoadjuvant therapy is regarded as an exceptionally favorable prognostic factor in locally advanced gastric and esophagogastric junction cancer. The incidence of disease progression in this subgroup and the factors that might predict it remain insufficiently studied, and no data are available for the Russian population. Aim: to assess the incidence of disease progression in patients with locally advanced gastric cancer, who achieved pCR after neoadjuvant therapy and to describe the clinical and morphological features of those in whom it occurred. Material and Methods. In a national multicenter retrospective cohort of 195 patients with pCR, who met the inclusion criteria and had adequate follow-up, disease progression was recorded in 11 (5.6 %). The clinical and morphological characteristics of patients with progression were compared with those of sex- and age-matched patients without progression (1:3). Descriptive statistics, Fisher exact test and the Mann–Whitney u test were used. Results. The median time from the start of treatment to progression was 22 months (range 12–48); progression was predominantly systemic (distant metastases 63.6 %, peritoneal carcinomatosis 45.5 %). Across the whole pCR cohort, cancer-specific survival was ~95.5 % at 2 years and ~94.7 % at 3 years. patients with progression somewhat more often had features of a more aggressive tumor course (cT4, a non-intestinal – diffuse or mixed – Lauren type), as well as postoperative complications grade III+, but none of these differences retained significance after correction for multiple comparisons, and none can be regarded as a reliable predictor of progression. Conclusion. Achievement of pCR is associated with an extremely low rate of disease progression and high cancer-specific survival. No reliable predictors of progression have been identified to date. The very small number of progression events does not allow a subgroup requiring adjuvant therapy to be defined and does not justify the routine use of adjuvant therapy (in particular, continued FLOT) in patients who have achieved a complete response.