Impact of Facility Radiation Patient Volume on Overall Survival in Patients with Muscle Invasive Bladder Cancer Undergoing Trimodality Bladder Preservation Therapy

Abstract

Background: There is an association between higher hospital and urologist case volume and improved survival outcomes for patients with bladder cancer. Less data on facility volume and outcomes exists following trimodality bladder preservation with TURBT followed by definitive chemoradiation (CRT). Materials and Methods: The National Cancer Database was queried for patients from 2004-2013 with urothelial bladder cancer (cT2-4aN0M0) receiving definitive CRT after TURBT. We compared OS between high-and low-bladder preservation case volume (BPCV) centers using Cox proportional hazard models. BPCV was dichotomized into high versus low volume at the 70th percentile level (i.e. high volume defined as top 30th percentile of cases and low volume defined as bottom 70th percentile of cases). Propensity matching was performed to match high-and low-volume centers. Results: A total of 666 treatment facilities treating 1,635 patients with bladder preservation were identified with a median follow-up of 26 months (range, 2-136 months). A 70th percentile cutoff identified 497 patients that received treatment at 64 high-volume facilities. Median OS of patients treated at high BPCV centers was 37.0 months (95% CI, 27.3-46.7) versus 32.3 months (95% CI, 27.9-33.6) for patients treated at low BPCV centers (P = 0.004). High BPCV facilities were independently associated with a decreased hazard of death (HR, 0.86, 95% CI, 0.75-0.98; P = 0.031). In the propensity score matched cohort, median OS of patients treated at high BPCV was 36.1 months (95% CI, 26.5-45.8) versus 28.1 months (95% CI, 23.9-32.3) for patients treated at a low BPCV facility (P = 0.016). Conclusions: In this observational cohort, treatment at a high BPCV facility was associated with improved OS. Causal factors for this finding may include superior bladder specific clinician expertise, technology, and multidisciplinary-care.

Systematic Review and Meta-analysis of the Association Between Radiation Therapy Treatment Volume and Patient Outcomes

“…Prostate cancer death over 10-y study period: HR, 1.07; 95% CI, 0.98-1.17; P = .14 4. All deaths over 10-y study period: HR, 0.99; 95% CI, 0.96-1.02; P = .48 Bladder cancer Bajaj et al; 2017 34 (USA) NCDB (n = 2763); 2004-2013 Muscle-invasive bladder cancer; TNM stage: T2-4, N0-3, M0 RT with/without CT (technique not specified) Dose: 60-70 Gy Age, sex, race, facility type, median case volume, ethnicity, Charlson-Deyo comorbidity score, insurance, median income, education level, census region, metropolitan area, year group, tumor grade, chemotherapy type, tumor group, radiation therapy dose, distance to hospital, extent of resection Categorical (dichotomized): Divided at the 75th percentile based on median case volume per facility over study period (10 y) HV facilities: top 25th LV facilities: bottom 75th Propensity-matched: no Sensitivity analysis performed: yes Volume effect seen on sensitivity analysis: no HV vs LV facilities: Adjusted overall survival over 100 mo: HR, 0.99; 95% CI, 0.94-1.04; P = .60 Fischer-Valuck et al; 2019 35 (USA) NCDB (n = 1635); 2004-2013 Muscle-invasive bladder cancer; TNM stage: T2-4, N0, M0 CRT Dose: 50.4-75 Gy Age, sex, race, tumor stage, Charlson-Deyo comorbidity, treatment facility type, radiation dose, radiation fractionation, number of chemotherapy agents, year of diagnosis, treatment facility location, insurance status, population setting, household income, education level, (all patients underwent TURBT before RT) Categorical (dichotomized): Divided at the 70th percentile based on the number of bladder preservation cases completed at each facility over the study period (10 y) HV facilities: ≥6 cases (top 30th) LV facilities: <6 cases (bottom 70th) Propensity-matched: yes Sensitivity analysis performed: yes Volume effect seen on sensitivity analysis: yes HV vs LV facilities: Median length of survival (mo): 36.1 (95% CI, 26.5-45.8) vs 28.1 (95% CI, 23.9-32.3) (all doses); 39.1 (95% CI, 29.3-48.8) vs 30.7 (95% CI, 27.6-33.7) (doses 59.4-64.8 Gy; n = 1213) Adjusted overall survival over 120 mo: HR, 0.82; 95% CI, 0.70-0.96; P = .016 (all doses); HR, 0.83; 95% CI, 0.73-0.96; P = .037 (doses 59.4-64.8 Gy; n = 1213) D'Rummo et al; 2019 36 (USA) NCDB (n = 7562); 2004-2015 Muscle-invasive bladder cancer; TNM stage: T2-4, 0-3, M0 EBRT with/without CT (techn...…”

“… Bladder cancer All 3 studies did not describe the radiation therapy technique used, for example, IMRT or 3D-CRT. Bajaj et al 34 specifically analyzed curative doses of 60-70 Gy; Fischer-Valuck et al 35 analyzed all doses between 50.4 and 75 Gy and standard curative fractionated doses of 59.4-64.8 Gy; and D'Rummo et al 36 analyzed all doses >30 Gy and curative doses of 55-60 Gy ( Table 1 ). Tchelebi et al 28 included only patients who received definitive radiation therapy doses via EBRT (technique not specified) and/or brachytherapy; however, specific doses were not mentioned.…”

Current Management of Localized Muscle-Invasive Bladder Cancer: A Consensus Guideline from the Genitourinary Medical Oncologists of Canada

“…Short-term treatment mortality likely favors TMT, especially in elderly patients [256]. Patients should be carefully selected for TMT (and NAC) through a multidisciplinary approach in experienced centres [257]. A multidisciplinary bladder clinic has been shown to significantly impact treatment selection and has potential to improve patient outcomes [119].…”

Impact of radiation therapy facility volume on survival in patients with cancer

“…However, of the 14 million patients diagnosed with cancer each year, approximately 1 quarter receive radiation therapy as part of the curative intent management of their disease 15,16 . Although existing studies show a survival benefit to receiving radiation therapy at high‐volume versus low‐volume centers, they only focus on a few disease sites, without accounting for receipt of surgery, and with variable definitions of facility volume 17‐24 …”