A Propensity Score Analysis of Chemotherapy Use in Patients with Resectable Gallbladder Cancer

Importance: Gallbladder cancer is uncommon but highly fatal. Surgery remains the only potentially curative treatment for localized or locoregionally advanced gallbladder cancer. The rate of use of neoadjuvant and adjuvant chemotherapy in resectable gallbladder cancer is unknown. Objective: To assess factors associated with the use of neoadjuvant and adjuvant chemotherapy in patients with resectable gallbladder cancer and survival outcomes. Design, Setting, and Participants: The National Cancer Database was used to identify 6391 adults who underwent definitive surgical resection for gallbladder cancers between January 1, 2004, and January 1, 2016. Data analysis was performed from January 15 to February 15, 2020. Patients with localized or locoregionally advanced gallbladder cancers (ie, categories cTx-cT4, cN0-2, and cM0) were categorized as receiving neoadjuvant chemotherapy, adjuvant chemotherapy, or surgery alone. Categorical variables were compared using the χ²test, with 1:3 nearest-neighbor propensity score matching based on neoadjuvant chemotherapy. Survival outcomes between groups were compared using Kaplan-Meier and Cox proportional hazards regression analyses. Main Outcomes and Measures: The use and survival outcomes of adjuvant and neoadjuvant chemotherapy. Results: Of 6391 patients who underwent definitive surgery for gallbladder cancer, 4559 were women (71.3%); median age was 68 (IQR, 59-77) years. A total of 3145 patients (49.2%) received adjuvant chemotherapy, 3145 patients (49.2%) underwent surgery without chemotherapy, and 101 patients (1.6%) received neoadjuvant chemotherapy. Neoadjuvant chemotherapy use was associated with treatment at an academic facility (61 patients [60%] vs 38 patients [38%] treated in a nonacademic facility; P <.001) and in those with private insurance (65 patients [65%] vs 11 patients [11%] with Medicaid insurance; P <.001). Surgery alone was frequently used in older patients (median age, 72 [IQR, 63-81] years vs 59 [IQR, 52-66] years in patients with neoadjuvant chemotherapy; P <.001), those with Medicare insurance (1925 patients [57%] vs 1438 patients [43%] with adjuvant chemotherapy; P <.001), and patients with a higher comorbidity index score (326 patients [62%] vs 197 patients [38%] with adjuvant chemotherapy; P <.001). Adjuvant or neoadjuvant chemotherapy was used more frequently than surgery in patients with node-positive cancer (1482 [67.2%] vs 53 [65.4%] vs 912 [49.7%]). On propensity score matching analysis, adjuvant chemotherapy was associated with longer survival than surgery alone (22 vs 18 months, hazard ratio [HR], 0.78; 95% CI, 0.63-0.96); survival with neoadjuvant chemotherapy was not statistically significant compared with surgery alone and adjuvant chemotherapy groups (27 months, HR, 0.78; 95% CI, 0.58-1.04). However, in patients with node-positive gallbladder cancer, neoadjuvant therapy was associated with longer median overall survival (30 months [95% CI, 24-36 months] vs 14 months [95% CI, 11-17] in patients with surgery alone; P =.002). Conclusions and Relevance: In this cohort study, use of adjuvant and neoadjuvant chemotherapy was low in patients with surgically resected gallbladder cancers. Chemotherapy was used more frequently than surgery in lymph node-positive disease compared with lymph node-negative disease. Adjuvant chemotherapy was associated with a survival advantage in resectable gallbladder cancer, and neoadjuvant chemotherapy was associated with increased survival in node-positive gallbladder cancers. These findings suggest that adjuvant chemotherapy and neoadjuvant chemotherapy should be considered in treatment of gallbladder cancer..