Does muscle invasive bladder cancer following pelvic radiotherapy portend worse prognosis? A seer-based study

Assessing the safety of bladder-preserving therapy as an alternative to surgical intervention in elderly patients with muscle invasive bladder cancer

BACKGROUND

There is interest in using bladder-preserving therapy as an alternative definitive therapy for muscle invasive bladder cancer in certain high-risk groups such as the elderly.

OBJECTIVE

To determine if bladder-preserving therapy represents a safer alternative to surgical intervention in elderly patients with muscle invasive bladder cancer.

METHODS

We surveyed the Surveillance, Epidemiology and End Results database (SEER) for cases of non-metastasized malignant bladder cancer in patients aged 80+. Survival outcomes with radical cystectomy (RC) with or without chemotherapy were compared to those after chemotherapy and radiation without cystectomy. We performed log-rank tests and Kaplan-Meier and cox regression and hazard analyses before and after propensity score matching.

RESULTS

A total of 2995 patients were identified, with 49.98% treated with RC only, 8.65% treated with RC/chemotherapy, and 41.37% treated with chemotherapy and radiation without RC. Median overall survival for the RC only, RC/chemotherapy and chemotherapy/radiation groups were 31.4, 44.1, and 24.6 months, respectively. On multivariate analysis, hazard ratios (reference: RC/chemotherapy group) were RC Only (HR = 1.408 (95% CI 1.188-1.669), p < 0.0001) and chemotherapy/radiation (HR = 1.650 (95% CI 1.390-1.959), p < 0.0001). After matching the chemotherapy/radiation and RC/chemotherapy groups, the former continued to show survival hazard (HR = 1.744 (95% CI 1.414-2.155), p < 0.0001).

CONCLUSIONS

Octogenarians should be offered definitive local therapy for their localized bladder cancer including RC and chemotherapy. Bladder-sparing alternatives should be reserved for patients unfit for surgery.

Clinical characterization of radiation-associated muscle-invasive bladder cancer

OBJECTIVE

To characterize the presentation, patterns of care, and outcomes of radiation-associated muscle-invasive bladder cancer (RA-MIBC) compared to primary (non-radiation associated) MIBC. RA-MIBC has been suggested to represent a more aggressive disease variant and be more difficult to treat compared to primary (non-radiation associated) MIBC.

METHODS

We identified 60,090 patients diagnosed with MIBC between 1988-2015 using the Surveillance, Epidemiology, and End Results database and stratified patients based on whether radiation had been administered to a prior pelvic primary cancer. We used Fine-Gray competing risks regression to compare adjusted bladder cancer-specific mortality (BCSM) for RA-MIBC compared to primary MIBC.

RESULTS

There were 1,093 patients with RA-MIBC and 58,997 patients with primary MIBC. RA-MIBCs were more likely to be T4 at diagnosis (21.0% vs 17.3%, P < .001), and less likely to be node-positive (10.3% vs 17.1%, P < .001). The rate of 5-year BCSM was significantly higher for patients with RA-MIBC vs primary MIBC (56.1% vs 35.3%, AHR 1.24, P < .001), even after stratification by other tumor, treatment and patient-specific factors.

CONCLUSION

RA-MIBCs tended to present with higher grade and T stage disease and were less likely to receive curative treatment. Even when accounting for stage, grade, and receipt of treatment, patients with RA-MIBC had worse survival compared to those with primary MIBC. These findings suggest that RA-MIBC present unique clinical challenges and may also represent a biologically more aggressive disease compared to primary MIBC. Future research is needed to better understand the biology of RA-MIBC and develop improved treatment approaches.