Adjuvant chemotherapy associated with an improved overall survival for patients with locally advanced gastric cancer

1. In this retrospective cohort study, 462 patients with locally advanced gastric cancer demonstrated a significantly improved survival after treatment with adjuvant chemotherapy compared to those who did not receive adjuvant chemotherapy.

2. Adjuvant chemotherapy was associated with an improved overall survival for patients with locally advanced gastric cancer with a lymph node ratio of at least 9%.

Evidence Rating Level: 2 (Good)

Study Rundown: Gastric cancer has more than 1 million newly diagnosed cases annually worldwide. While surgical techniques are continuously being developed and refined to improve prognosis, survival outcomes for patients diagnosed with locally advanced gastric cancer (LAGC) remain poor. This cohort study compared the survival rates between patients with LAGC who received adjuvant chemotherapy (AC) after neoadjuvant therapy (NAC) compared to those who did not, both after undergoing surgical resection. The main exposure of this study was patients who received AC in comparison to those who did not. The primary outcomes were overall survival (OS), disease-free survival (DFS), and disease-specific survival (DSS). A total of 353 patients from China were recruited for this study between June 2008 to December 2017, with a mean age of 58 years and 78% were men. 262 patients received AC and 91 patients did not. Patients in the AC group were defined as those who underwent 1 or more postoperative AC cycles within 3 months after surgical resection of LAGC. The 3-year overall survival rate was found to be significantly higher in patients who received AC, compared to those who did not. In particular, lymph node ratio was found to be associated with AC benefits, and patients with a lymph node ratio of at least 9% experienced improved outcomes. A major strength of this study was that it is the first multicenter, international cohort study to demonstrate a meaningful association between LNR and improved prognosis associated with AC in patients with LAGC. Finally, although propensity-matching was performed, a limitation is the potential for selection bias due to the nonrandomized assignment of treatment that may have still occurred.

Click to read the study in JAMA Network Open

Relevant Reading: Perioperative chemotherapy versus surgery alone for resectable gastroesophageal cancer

In-Depth [retrospective cohort]: This cohort study investigated whether adjuvant chemotherapy (AC) was associated with a survival benefit in patients diagnosed with locally advanced gastric cancer (LAGC) undergoing a curative-intent gastrectomy after neoadjuvant chemotherapy (NAC). A total of 353 patients were recruited for this study between June 2008 and December 2017 (275 [78.1%] male; mean [SD] age, 58.0 [10.7] years. 262 patients received postoperative AC after NAC and surgical resection, and 91 patients did not receive further treatment after NAC and surgical resection of LAGC. The primary outcomes of this study were overall survival (OS), disease-free survival (DFS) and disease-specific survival (DSS. After propensity matching, the 3 year-OS was significantly higher in patients who received AC (60.1%, 95% CI, 53.1%-68.1%) in comparison to those who did not receive AC (49.3%; 95% CI, 39.8%-61.0%) (P= .02). A subgroup analysis divided patients into those with a lymph node ratio (LNR) either less than or greater than 9%. 132 patients with an LNR of 9% or greater were associated with a significantly improved prognosis upon receipt of AC in comparison to those who did not receive AC (3-year OS: 46.6% vs 21.7%, P <.001; 3-year DFS 49.5% vs 20.0%, P <.001; 3-year DSS: 51.1% vs 22.5%, P < .001). The multivariate analysis also demonstrated that AC was associated with improved survival outcomes in patients with LAGC with an LNR greater than 9% (OS: HR, 0.45; 95% CI, 0.29-0.69; P =.007; DFS: HR, 0.47; CI 95%, 0.30-0.73; P = .008; DSS: HR, 0.47; 95% CI, 0.30-0.72; P=.007). In patients with an LNR of 9% of greater, survival rates were found to be significantly better for those who completed at least 4 cycles of AC, compared to those who did not receive AC (6-months: HR, 0.56, 95% CI, 0.33-0.96; P =.03; 9-months: HR, 0.50; 95% CI, 0.27-0.94; P=.03). With this, LNR has the potential to be used in clinical decision-making regarding AC planning for patients with LAGC.

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