Oral Antimetabolite After Surgery Associated With Survival Benefit in Biliary Tract Cancer

Data from a phase 3 trial demonstrated that the use of the oral antimetabolite fluoropyrimidine derivative S-1 after surgical resection for biliary tract cancer induced a better survival outcome than surgery alone.

The findings, which were recently presented at the 2022 American Society of Clinical Oncology (ASCO) Gastrointestinal Cancers Symposium, led the study authors to recommend the regimen as standard of care for this patient population.

“Adjuvant S-1 therapy led to significantly longer survival than surgery alone (in) patients with resected (biliary tract cancer),” Dr. Masafumi Ikeda, of the Department of Hepatobiliary and Pancreatic Oncology at National Cancer Center Hospital East in Japan, said during a presentation of the results.

The trial included 440 patients, 222 of which received surgery alone (median age, 70 years; 68% male). Patients who received the oral antimetabolite (median age, 68 years; 74% male) were administered a dose of 40 mg/m2 twice a day for four weeks followed by two weeks off treatment for four cycles.

Enrolled patients were aged 20 to 80 years old and received curative surgery to resect their bile duct.

The data demonstrated that treatment with the oral antimetabolite derivative induced a three-year overall survival rate of 77.1% compared with 67.6% in the group that received surgery alone. Use of the study drug after surgery was also associated with a better three-year relapse-free survival rate than surgery alone (62.4% vs 50.9%, respectively).

More than half of the patients in both the surgery alone (59%) and treatment after surgery (58%) group presented with stage 2 biliary tract cancer.

Further analyses of the data also indicated a survival benefit with the oral antimetabolite derivative after surgery across several patient subgroups.

The most common severe side effect in those who received the antimetabolite derivative was a decrease in neutrophils (14%) compared with 1% in those who were treated with only surgery. Of note, a decrease in neutrophils may put individuals at an increased risk for developing infections. Other common severe side effects included but were not limited to anemia (4% vs 1%) and diarrhea (3% vs 0%).

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