Management of Metastatic Gastric Cancer
HER2-NEGATIVE DISEASE
For patients with HER2-negative disease, National Comprehensive Cancer Network (NCCN) guidelines recommend using 2-drug combination regimens rather than 3 drugs, given concern for increased toxicity with 3-drug regimens.17 For patients with a performance status of 0 to 1, utilization of a 3-drug regimen is a reasonable alternative. The combination of a fluoropyrimidine with a platinum agent is considered the standard of care, with regimens such as fluorouracil, leucovorin, and oxaliplatin (FOLFOX) being commonly used.
Epirubicin-containing regimens have also been extensively studied in advanced gastric cancer. In a study of 274 previously untreated patients with GEJ cancers, the combination of epirubicin, cisplatin, and fluorouracil (ECF) was compared to fluorouracil, doxorubicin, and methotrexate (FAMTX). There was an OS benefit favoring ECF (8.9 months versus 5.7 months) at 1 year (95% CI 27% to 45%, P = 0.0009). The ECF regimen was associated with an increased risk of nausea, emesis, and alopecia, while more hematologic toxicity and infections were noted with the FAMTX regimen.18 In addition, in a phase 3 trial, Van Cutsem and colleagues examined the role of docetaxel in combination with cisplatin and fluorouracil (DCF) compared to cisplatin and fluorouracil alone. Addition of docetaxel led to improved OS and time to progression (9.2 months versus 8.6 months for cisplatin and fluorouracil alone, P = 0.02) but with an increased risk of grade 3 and 4 toxicities (69% versus 59%). These adverse events included neutropenia (82% versus 57% of cisplatin and fluorouracil patients), diarrhea (19% versus 8%), stomatitis (21% versus 27%), and fatigue (19% versus 14%).19
The landmark phase 3 REAL-2 study compared 4 chemotherapy regimens in patients with untreated advanced esophagogastric cancer. This study was conducted to determine if the efficacy of cisplatin and oxaliplatin, a third-generation platinum agent, is equivalent to that of fluorouracil and capecitabine, an oral fluoropyrimidine. In this trial, a 2 × 2 design was used to compare 4 regimens: ECF versus epirubicin, cisplatin, and capecitabine (ECX) versus epirubicin, oxaliplatin, and fluorouracil (EOF) versus epirubicin, oxaliplatin, and capecitabine (EOX). The study found EOX to be noninferior to ECF, with a trend towards improved OS compared to other combination regimens (11.2 months versus 9.9 months, HR 0.80 [95% CI 0.66 to 0.97], P = 0.02).20 Thus, the study demonstrated that an oxaliplatin and capecitabine-based regimen could replace cisplatin and fluorouracil. Given that fluorouracil administration requires long continuous infusions, the oral-based capecitabine regimen is an attractive option for patients.
Several trials have demonstrated the equivalency of oxaliplatin with cisplatin in combination regimens for the treatment of advanced gastric cancer. Oxaliplatin has the benefit of an improved toxicity profile as compared to cisplatin, with the major dose-limiting toxicity being peripheral neuropathy
Given previous evidence that DCF (docetaxel, cisplatin, fluorouracil) is superior to cisplatin and fluorouracil alone, there was interest in determining if the addition of docetaxel to a backbone of fluorouracil, oxaliplatin, and leucovorin (FLO) could elicit a higher response rate. This concept was investigated in a phase 2 trial that assigned 54 patients with metastatic gastric or GEJ adenocarcinoma to receive biweekly infusions of oxaliplatin, leucovorin, fluorouracil, and docetaxel.21 Median time to response was 1.54 months, and the overall response rate was 57.7%. Median progression-free survival (PFS) was 5.2 months, and OS was 11.1 months. The most common grade 3 or 4 toxicities included neutropenia (48%), leukopenia (27.8%), diarrhea (14.8%), and fatigue (11.1%).
