Associations Between Female Sex and Treatment Patterns and Outcomes for Muscle-invasive Bladder Cancer

The sex gap in bladder cancer survival - a missing link in bladder cancer care?

The differences in bladder cancer outcomes between the sexes has again been highlighted. Uncommon among cancers, bladder cancer outcomes are notably worse for women than for men. Furthermore, bladder cancer is three to four times more common among men than among women. Factors that might explain these sex differences include understanding the importance of haematuria as a symptom of bladder cancer by both clinicians and patients, the resultant delays in diagnosis and referral of women with haematuria, and health-care access. Notably, these factors seem to have geographical variation and are not consistent across all health-care systems. Likewise, data relating to sex-specific treatment responses for patients with non-muscle-invasive or muscle-invasive bladder cancer are inconsistent. The influence of differences in the microbiome, bladder wall thickness and urine dwell times remain to be elucidated. The interplay of hormone signalling, gene expression, immunology and the tumour microenvironment remains complex but probably underpins the sexual dimorphism in disease incidence and stage and histology at presentation. The contribution of these biological phenomena to sex-specific outcome differences is probable, albeit potentially treatment-specific, and further understanding is required. Notwithstanding these aspects, we identify opportunities to harness biological differences to improve treatment outcomes, as well as areas of fundamental and translational research to pursue. At the level of policy and health-care delivery, improvements can be made across the domains of patient awareness, clinician education, referral pathways and guideline-based care. Together, we aim to highlight opportunities to close the sex gap in bladder cancer outcomes.

Biological differences underlying sex and gender disparities in bladder cancer: current synopsis and future directions

Sex and gender disparities in bladder cancer have long been a subject of interest to the cancer research community, wherein men have a 4 times higher incidence rate than women, and female patients often present with higher-grade disease and experience worse outcomes. Despite the known differences in disease incidence and clinical outcomes between male and female bladder cancer patients, clinical management remains the same. In this review, we critically analyze studies that report on the biological differences between men and women and evaluate how these differences contribute to sex and gender disparities in bladder cancer. Distinct characteristics of the male and female immune systems, differences in circulating hormone levels and hormone receptor expression, and different genetic and epigenetic alterations are major biological factors that all likely contribute to disparate incidence rates and outcomes for male and female bladder cancer patients. Future preclinical and clinical studies in this area should employ experimental approaches that account for and consider sex and gender disparities in bladder cancer, thereby facilitating the development of precision medicine for the effective treatment of bladder cancer in all patients.

Effects of treatments on gender differences in patients with localized muscle-invasive bladder cancer

PURPOSE

To explore the gender differences in survival under different treatments in localized muscle-invasive bladder cancer (MIBC), and to find clinical strategies to improve the poor prognosis of female with bladder cancer (BC).

METHODS

Patients with localized MIBC were collected in the SEER database from 2010 to 2016 to analyze the gender differences in clinical characteristics. Propensity score matching was used to balance the effects of confounding factors. Kaplan-Meier method and Cox proportional hazards regression model were performed to compare the overall survival (OS) and cancer-specific survival (CSS) of patients between different treatment subgroups.

RESULTS

The entire cohort included 13,272 T2N0M0 MIBC patients, with a male-to-female incidence of 3:1. Compared with male patients, females had a higher age of onset and more blacks. There were more female patients undergoing bladder-sparing surgery (BSS) alone, and the OS and CSS were worse than those in males. The gender difference showed statistical significance in the BSS group, but not in the radical cystectomy (RC) group.

CONCLUSION

The survival of localized MIBC patients can be affected by treatments. Multi-modality treatment and RC may improve the survival prognosis of female patients.

Mortality Trends Related to Bladder Cancer in Spain, 1999-2018

Bladder cancer (BC) is an important cause of premature mortality (PM, <75 years). Spain has one of the highest BC mortality rates in Europe. The objective of this study was to analyse BC mortality trends between 1999 and 2018 in Spain. The study was based on data from the National Institute of Statistics (Instituto Nacional de Estadística-INE). Age-adjusted mortality rates (AAMRs) were calculated by sex and age group. A trend analysis was performed using Joinpoint regression models and years of potential life lost (YPLL). Mortality in men resulting from BC decreased in all age groups studied. This was not observed in women, for whom mortality only decreased in the ≥75 age group. Deaths due to BC occurred prematurely in 38.6% of men and in 23.8% of women, which indicated a greater impact on YPLL in men compared to women. Over the last 20 years, there has been a significant decrease in BC mortality rate, except in women under 75 years of age. Despite this temporal trend of decreasing mortality, BC continues to have a significant impact on YPLL, mainly in men. Given this context, it is important to direct more resources towards prevention and early diagnosis strategies to correct this situation.

Sex differences in treatment patterns for non-advanced muscle-invasive bladder cancer: a descriptive analysis of 3484 patients of the Netherlands Cancer Registry

PURPOSE

Bladder cancer (BC) is a common malignancy with well-established differences in incidence, clinical manifestation and outcomes between men and women. It is unknown to what extent disparities in outcomes are influenced by differences in treatment approaches. This paper describes treatment patterns among men and women with muscle-invasive BC focusing on curative treatment (radical cystectomy or trimodal therapy).

METHODS

A retrospective population-based cohort study was performed with data from the Netherlands Cancer Registry. All patients newly diagnosed with muscle-invasive, non-advanced BC (MIBC, cT2-4a, N0/X, M0/X) in the years 2018, 2019 and 2020 were identified. Patient and tumor characteristics and initial treatment were compared between men and women with descriptive statistics and multivariable logistic regression analyses.

RESULTS

A total of 3484 patients were diagnosed with non-advanced MIBC in 2018-2020 in the Netherlands, of whom 28% were women. Women had higher T-stage and more often non-urothelial histology. Among all strata of clinical T-stage, women less often received treatment with curative intent (radical cystectomy [RC] or trimodality treatment). Among RC-treated patients, women more often received neoadjuvant treatment (except for cT4a disease). After adjustment for pre-treatment factors, odds ratios were indicative of women having lower probability of receiving curative treatment and RC specifically, and higher probability to receive NAC when treated with RC then men, although not statistically significant.

CONCLUSIONS

Considerable differences in treatment patterns between men and women with MIBC exist. A more considerate role of the patient's sex in treatment decisions could help decrease these differences and might mitigate disparities in outcomes.

Gender Differences in Urothelial Bladder Cancer: Effects of Natural Killer Lymphocyte Immunity

Men are more likely to develop cancer than women. In fact, male predominance is one of the most consistent cancer epidemiology findings. Additionally, men have a poorer prognosis and an increased risk of secondary malignancies compared to women. These differences have been investigated in order to better understand cancer and to better treat both men and women. In this review, we discuss factors that may cause this gender difference, focusing on urothelial bladder cancer (UBC) pathogenesis. We consider physiological factors that may cause higher male cancer rates, including differences in X chromosome gene expression. We discuss how androgens may promote bladder cancer development directly by stimulating bladder urothelium and indirectly by suppressing immunity. We are particularly interested in the role of natural killer (NK) cells in anti-cancer immunity.

Gender-specific Stratification of Survival Following Immune Checkpoint Inhibitor Therapy Based on Intratumoral Expression of a B cell Gene Signature

BACKGROUND

There is a great need to identify biomarkers that can accurately identify patients who will obtain the most clinical benefit from immune checkpoint inhibitor (ICI) therapy. While high intratumoral B cell gene expression correlated with an ICI response in melanoma, whether it adds predictive value in other cancers is unknown.

OBJECTIVE

To examine the relationship between B cell gene signature (BCGS) expression and overall survival (OS) following ICI treatment.

DESIGN, SETTING, AND PARTICIPANTS

A total of 348 patients with advanced urothelial carcinoma from the IMvigor 210 phase 2 clinical trial of atezolizumab and 406 patients with muscle-invasive bladder cancer from The Cancer Genome Atlas (TCGA) were included.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We analyzed tumor RNA sequencing data of included patients to examine the relationships between a BCGS and clinical outcomes.

RESULTS AND LIMITATIONS

Tumors with high levels of B cell and CD8+ T cell gene signatures (BCGS/CD8TGS or B8T high/high) were associated with the longest OS of all B8T groups. Moreover, the B8T cell signature stratified patients whose tumors had a high tumor mutational burden or high programmed death ligand 1 (PD-L1) into subsets with differential OS outcomes. Whereas the B8T high/high tumors were associated with the best clinical outcomes in ICI-treated men, they were not associated with better OS in women. Conversely, women with B8T high/high tumors had the best clinical outcomes in non-ICI-treated muscle-invasive bladder cancer.

CONCLUSIONS

These data suggest that the B8T signature can enhance OS stratification in patients with advanced urothelial carcinoma who are treated with ICI therapy and that sex-specific differences in the tumor immune microenvironment may drive disparate outcomes.

PATIENT SUMMARY

We examined whether the presence of two immune cell gene signatures within tumor samples impact survival in patients with bladder cancer. High levels of both of these signatures (B cells and CD8+ T cells) associate with superior survival in patients who receive immune therapy.