E258: Survival Benefit of Adjuvant Chemotherapy in Resected Squamous Carcinoma of the Gallbladder

Squamous carcinoma of the gallbladder is an uncommon malignancy and therefore evidence-based recommendations are limited with no formal guidelines recommending adjuvant treatment. Given the known aggressive nature and poor prognosis of squamous carcinoma the gallbladder, we hypothesize adjuvant systemic treatment of resected squamous carcinoma of the gallbladder may improve overall survival in patients undergoing resection.

Methods:

Using the National Cancer Database, all patients with adenosquamous and squamous carcinoma < ![if !supportAnnotations] >[BR1]< ![endif] > of the gallbladder (SGBC) who underwent definitive surgical resection from 2004-2020 were identified. Patients were stratified by receipt of adjuvant chemotherapy. Univariate and multivariable survival analysis was performed.
 

Results:

Of the 1,048 patients with SGBC undergoing surgical resection, 47.2% (495) received adjuvant chemotherapy. Patients who received adjuvant chemotherapy were younger (66 vs 73), a higher percentage had private insurance (34.7% vs 20.8%) and were treated at an academic center (64.8% vs 51.5%) compared to those who did not receive adjuvant chemotherapy (all p< .001). 49.8% of patients with SGBC had a lymphadenectomy at time of surgical resection. Of those receiving adjuvant chemotherapy, 57.4% (284/495) received multiagent chemotherapy regimens.  Overall survival was significantly longer in those who received adjuvant chemotherapy (11.3 months vs 5.3 months, p< .001) (Figure 1). Multivariable survival analysis adjusting for margin status, histology, extent of surgery, pathologic stage, and receipt of radiation demonstrated decreased mortality associated with receipt of adjuvant chemotherapy (HR 0.62, p< .001) compared to those not receiving adjuvant chemotherapy.

Conclusions:

SGBC is an aggressive malignancy with poor prognosis. This study demonstrates that patients with SGBC derive an overall survival benefit from receipt of adjuvant chemotherapy. Guidelines should be addended to reflect SGBC as a unique entity and recommendations should be made for adjuvant treatment in patients who undergo surgical resection of SGBC.