Downstaging and survival after Neoadjuvant chemotherapy for bladder cancer in Norway; a population-based study.

BACKGROUND: Neoadjuvant chemotherapy (NAC) before radical cystectomy is associated with pathological downstaging (DS) and improved overall survival (OS) in patients with muscle-invasive bladder cancer (MIBC). Population-based studies have not unequivocally shown improved survival. The aim of this population-based study was to evaluate the effect of NAC on DS and OS in Norwegian patients with MIBC. METHODS: Patients in the Cancer Registry of Norway undergoing radical cystectomy (2008-2015) with or without NAC diagnosed with MIBC between 2008 and 2012 were included. Follow-up data were available until 31 December 2019. Logistic regression estimated the odds of DS with NAC, and a Cox model investigated the effect of DS on OS. Cox models, a mediator analysis and an instrumental variable approach were used to investigate the effect of NAC on OS. RESULTS: A total of 575 patients were included. NAC was administered to 82 (14%) patients. Compared to cystectomy only, NAC increased the proportion (43% vs. 22%) and the odds of DS (OR 2.51, CI 1.37-4.60, p = 0.003). Independent of NAC, the proportion of pN0 was higher in patients with DS (89% vs. 60%) and DS yielded a 78% mortality risk reduction (HR 0.22, CI 0.15-0.34, p = 1.9∙10-12), compared to patients without DS. We did not find an association between NAC and OS, neither by Cox regression (HR 1.16, CI 0.80-1.68, p = 0.417) nor by an instrumental variable approach (HR = 0.56, CI = 0.07-4.57, p = 0.586). The mediation analysis (p = 0.026) confirmed an indirect effect of NAC on OS through DS. Limitations include limited information of the primary tumour, details of NAC treatment and treatment indications. CONCLUSIONS: NAC increases the probability of DS and is indirectly associated to OS. DS is related to the absence of regional lymph node metastases and is associated with an OS benefit. Improved staging and biomarkers are needed to identify patients most likely to achieve DS and to benefit from NAC.

Initial management and survival of patients with primary metastatic bladder cancer before the immunotherapy era: a population-based study from Norway.

Before immunotherapy became part of the management of metastatic bladder cancer (mBC), systemic anti-cancer treatment comprised primarily of platinum-based chemotherapy. The objective of this study was to describe the characteristics, the initial management, overall survival (OS) and hospitalisations of patients with mBC before 2018 when immunotherapy for mBC was introduced in Norway.  Material and methods: It is a nationwide population-based study of primary mBC patients (diagnosed 2008-16). Descriptive statistics were applied and stratified for four initial management options (≤150 days after BC diagnosis): chemotherapy, major local treatment (cystectomy/pelvic radiotherapy), multimodal treatment (chemotherapy and local) and no anti-cancer treatment beyond transurethral resection of bladder tumour (untreated). Group differences were evaluated by Chi-square and Kruskal-Wallis test; OS was estimated with Kaplan-Meier. Results: Of the 305 patients included, 76 (25%) patients had chemotherapy, 46 (15%) patients had major local treatment, 21 (7%) patients had multimodal treatment and 162 (53%) patients were untreated.  Median OS ranged from 2.3 months (untreated) to 9.8 months (chemotherapy). Patients who received treatment had a higher rate of hospitalisation, with a median stay of three to four times that of untreated patients. Conclusion: Before immunotherapy, more than 50% of patients with primary mBC did not receive any initial anti-cancer therapy and had a poor survival. Patients treated with chemotherapy had inferior median OS compared to those treated with comparable systemic strategies in contemporary trials. Our results provide a basis for future research on treatment and survival after the introduction of immunotherapy for mBC, aiming to improve the care and outcome of patients with mBC.

Primary versus secondary muscle-invasive bladder cancer: survival after curative treatment.

PURPOSE: To assess if cancer-specific survival (CSS) following curative intent treatment (CIT) for muscle-invasive bladder cancer (MIBC) differs between patients presenting with MIBC (primary) and patients presenting with non-muscle-invasive bladder cancer who progress to MIBC (secondary). METHODS: This study uses data from the Cancer Registry of Norway on patients initially diagnosed with bladder cancer in 2008-2012 and treated with radical cystectomy (RC) or radiotherapy (RT). To ensure a clinically relevant population, we selected patients with a pre-treatment histology confirming muscle-invasion. Survival models were applied to evaluate differences in observed and adjusted CSS by type of MIBC and stratified by type of CIT. Adjustment was made for age group, sex, previous cancer, diagnostic hospital's academic status and geographical region, and type of CIT. RESULTS: We identified 650 eligible patients: 589 (91%) primary MIBC and 61 (9%) secondary MIBC. A total of 556 (86%) patients underwent RC and 94 (14%) RT. The 5-year CSS for primary MIBC was 56% and 59% for secondary MIBC (p = 0.68). The type of MIBC did not impact the risk of bladder cancer death (HR = 0.85, CI = 0.55-1.33, p = 0.48), nor when stratified for CIT (RC: HR = 0.93, CI = 0.57-1.53, p = 0.78); RT: HR = 0.71, CI = 0.24-2.16, p = 0.55). CONCLUSION: This first nation-wide population-based study comparing CSS between primary and secondary MIBC showed no significant difference in survival regardless of type of CIT. Continued surveillance of patients with non-muscle-invasive bladder cancer is necessary to detect early progression to MIBC. Future studies should include molecular and genetic characteristics in addition to detailed clinicopathologic information.