Prognostic factors in metastatic gastric cancer – let’s take a step forward

Abstract

Introduction: Gastric cancer is the fourth cancer worldwide and the second leading cause of cancer related mortality. Decision-making and prognosis is determined mostly by TNM. Median disease specific survival in metastatic setting is 10 months with a 5-year OS around 3-5%. Few studies identified important prognostic factors such as extent of metastatic disease, tumor markers, age, sex and receipt of treatment in these patients. Methods: We retrospectively reviewed clinical data from patients diagnosed with metastatic gastric cancer between 2006-2012 in our institute. We aimed to identify the most important prognostic factors besides TNM. Survival analysis was carried using Kaplan-Meier method. Results: In a total of 85 patients, 68.2% male, median age was 64 (34-80 years). Most patient had a good performance status (ECOG) - 38.8% 0 and 47.1% 1. The tumor grade was III (60%), I (30%) and II (10%). Primary lesion was located in the antrum (46.3%), gastric fundus/body/small curvature (32.5%) and cardia (21.3%). Stage IV was present on diagnosis in 82.1%. The metastatic sites were liver (45.8%), peritoneum (29.4%), lymph node (29.4%), lung (12.9%), pancreas (7.1%), colon (4.7%), bone (3.5%), pleura (3.5%), ovary (3.5%), kidney (2.4%) and spleen (1.2%). There was a median number of metastatic sites of 1 - 1 (66.7%), 2 (22.6%), 3 (7.1%) or 4 (3.6%). Patients presented with significant weight loss in 35.3%. The first treatment approach was palliative chemotherapy in 64.3% of patients and best supportive care (BSC) in 35.7%. The median number of chemotherapy lines was 1: 1 (39.3%), 2 (20.2%), 3 (1.2%), 4 (2.4%) and 6 (1.2%). Regarding major toxicity (grade III/IV), we reported neutropenia (14.1%), thrombocytopenia (2.4%), vomiting (2.4%), anemia (1.2%) and mucositis (1.2%). There was disease progression in 27.1% of patients, most commonly in bone (8.3%), loco regional (9.4%) and hepatic (5.9%) sites. Regarding survival, OS and PFS were significantly influenced (p<0.05) by gender, age, pleural metastasis, previous surgery to primary lesion and occurrence of neutropenia. Pancreatic metastasis had a negative influence on OS but not on PFS. Ovary and renal metastasis had a negative tendency on OS and PFS. The number of lines of chemotherapy had a positive tendency on OS. The median OS was 6.9 months, with a 12 months survival rate of 22.6% and the median PFS was 17.96 months with a 12 months PFS rate of 63.7%. Considering specific subgroups: for male population, pleural metastasis, treatment choice (BSC), neutropenia and pancreatic metastasis had a significant negative influence on OS; For females, ovary metastasis and age were the only factors affecting OS. For the diffuse type adenocarcinoma, there was a significant correlation between CA72.4 values and OS and PFS which was not found for the intestinal type. Conclusion: The average oncologist will face many cases of incurable gastric cancer. Gender (male), age (> 64 years), pleural metastasis and neutropenia had a negative and surgical approach of primary lesion had a positive prognostic impact. In some subgroups, tumor markers (CA72.4) can have a good prognostic value. Future studies need to investigate socioeconomics and molecular status.