Conversion therapy for disseminated gastric cancer. Interim results of a retrospective analysis of our own data

Background. Despite the development of new, more effective drug combinations, the increase in life expectancy of patients with disseminated gastric cancer (dGC) does not exceed 3.5 months. In this regard, new ways to improve long-term treatment results are being sought. One of these direction is conversion treatment – a combination of drug therapy with a surgical method in case of achieving stable control of the disease against the background of effective chemotherapy and the possibility of complete removal of all tumor foci (R0).

Objective. Evaluation of the long-term results of conversion therapy of patients with dGC and identification of predictive factors for overall survival. Goals: 1) assessment of progression-free survival; 2) assessment of overall survival with conversion treatment; 4) determination of prognostic factors for overall survival; 5) determination of the optimal timing of surgical treatment; 6) evaluation of event-free and postoperative survival.

Methods. The analysis included 55 operated patients with morphologically confirmed dGC aged from 21 to 77 years (median 50.5 years), male/female – 33/22, ECOG status 0–1 in 94.5% of patients. According to the histological structure, the signet ring cell variant (49.1%) and the diffuse subtype according to the Lauren classification (54.6%) predominated. Initially, ascites was detected in 23.64% of patients, metastases in the peritoneum – in 61.8%, in retroperitoneal lymph nodes – in 20%, in peripheral lymph nodes – in 10.9%, in the liver – in 18.18%, in the ovaries – in 12.73% of women. Localization of metastases in 1 anatomical area (zone) was noted in 22 (40%), in 2 areas - in 26 (47.3%), in 3 or more – in 7 (12.7%) patients. All patients received one line of chemotherapy (CT) for 18 weeks, in the FOLFIRINOX regimen – 19 (34.5%) patients, in the FLOT/mDCF regimen - 22 (40%), platinum-fluoropyrimidine doublets (XELOX, mFOLFOX6) – 14 (25.5%). R0 surgery was performed in 53 (96.3%) patients, R1-R2 – in 2. The median overall survival (mOS) was 29.33 months, 1-year survival – 85.5%, 3-year – 25.5%, 5-year – 9.1%. Median progression-free survival (mPFS) was 18.5 months, median event-free survival – 9.8 months, and median postoperative OS – 20.47 months. A significant increase in OS was obtained with an follow-up period interval from the date of completion of chemotherapy to the date of surgery of more than 3.4 months. The independent factors for a favorable prognosis of OS in a multivariate analysis were: 1) non-signet ring cell morphological variant; 2) absence of lymphovascular invasion; 3) FOLFIRINOX mode.

Conclusion. Conversion therapy for dGC is a promising area that can provide long-term survival for some patients.