PERIOPERATIVE CHEMOTHERAPY, ADJUVANT CHEMOTHERAPY AND ADJUVANT CHEMORADIOTHERAPY IN THE SURGICAL TREATMENT OF GASTRIC CANCER IN A HOSPITAL OF THE BRAZILIAN UNIFIED HEALTH SYSTEM.

Background: Despite the preference for multimodal treatment for gastric cancer, abandonment of chemotherapy treatment as well as the need for upfront surgery in obstructed patients brings negative impacts on the treatment. The difficulty of accessing treatment in specialized centers in the Brazilian Unified National Health System (SUS) scenario is an aggravating factor.

Aims: To identify advantages, prognostic factors, complications, and neoadjuvant and adjuvant therapies survival in gastric cancer treatment in SUS setting.

Methods: The retrospective study included 81 patients with gastric adenocarcinoma who underwent treatment according to INT0116 trial (adjuvant chemoradiotherapy), CLASSIC trial (adjuvant chemotherapy), FLOT4-AIO trial (perioperative chemotherapy), and surgery with curative intention (R0 resection and D2 lymphadenectomy) in a single cancer center between 2015 and 2020. Individuals with other histological types, gastric stump, esophageal cancer, other treatment protocols, and stage Ia or IV were excluded.

Results: Patients were grouped into FLOT4-AIO (26 patients), CLASSIC (25 patients), and INT0116 (30 patients). The average age was 61 years old. More than 60% of patients had pathological stage III. The treatment completion rate was 56%. The pathological complete response rate of the FLOT4-AIO group was 7.7%. Among the prognostic factors that impacted overall survival and disease-free survival were alcoholism, early postoperative complications, and anatomopathological status pN2 and pN3. The 3-year overall survival rate was 64.9%, with the CLASSIC subgroup having the best survival (79.8%).

Conclusions: The treatment strategy for gastric cancer varies according to the need for initial surgery. The CLASSIC subgroup had better overall survival and disease-free survival. The INT0116 regimen also protected against mortality, but not with statistical significance. Although FLOT4-AIO is the preferred treatment, the difficulty in carrying out neoadjuvant treatment in SUS scenario had a negative impact on the results due to the criticality of food intake and worse treatment tolerance.