An observational study found that adjuvant chemotherapy improves overall survival in patients with locally advanced bladder cancer.
Adjuvant chemotherapy trials in bladder cancer suffer from poor accrual, which makes discerning benefits for patients difficult. To circumvent the accrual issue, researchers conducted an observational study of real-world patients with locally advanced bladder cancer who were eligible for surgery. The results of the study were published in the Journal of Clinical Oncology.
Matthew D. Galsky, MD, of Mount Sinai School of Medicine in New York City, and colleagues identified 5,653 patients with pathologic T3-4 and/or pathologic node-positive bladder cancer through the National Cancer Data Base, which includes about 70% of all newly diagnosed cancer patients. Twenty-three percent of patients (1,293 patients) had received adjuvant chemotherapy after a cystectomy, and 4,360 had a cystectomy and were followed with observation.
Stratified analyses adjusted for propensity score demonstrated a 30% decreased risk of dying for patients who received adjuvant chemotherapy compared with patients who did not (hazard ratio, 0.70). The link between adjuvant chemotherapy and improvement in survival was consistent among all patient subgroups, including those with poor performance status.
The 5-year overall survival rate was 37.0% in the adjuvant chemotherapy group vs 29.1% in the observation group (P < .001).
Patients who received adjuvant chemotherapy were younger and more likely to live in areas of higher median income and a higher percentage of high school graduates; they were less likely to have multiple comorbidities (P < .05 for all comparisons).
Adjuvant chemotherapy is often incorporated into the treatment plan for patients with localized bladder cancer, since about half of patients who undergo potentially curative radical cystectomy progress to metastatic disease. Two prior randomized trials also showed a survival advantage after neoadjuvant chemotherapy, yet use in this setting has been limited. Three recent trials have attempted to test current chemotherapy regimens in the adjuvant setting for patients with locally advanced bladder cancer, but all three trials had accrual of less than 40% of their target populations and closed early.
In an accompanying editorial, Sumanta K. Pal, MD, of City of Hope Comprehensive Cancer Center in Duarte, California, and colleagues acknowledged that there is no substitute for valid prospective evidence. “However, because of the limitations cited previously with randomized prospective studies (eg, incomplete enrollment, methodologic issues), current trial data will be insufficient to guide use of adjuvant therapy. Galsky et al provide compelling evidence to support the practice, albeit with certain caveats,” including the lack of knowledge on exact chemotherapy regimens used, the absence of information on recurrence and timing of potential salvage chemotherapy, and the potential for missing data that could have led to imbalances in the study’s analysis.
Still, they concluded, “The data from Galsky et al will likely make the recommendation for adjuvant treatment more emphatic.”