Date Published: March 13, 2018
Author(s): Fiorina Kyritsi, Christopher A. Loffredo, Yun-Ling Zheng, George Philips, Sania Amr.
We investigated gender differences in the histopathologic presentation of bladder cancer cases in Egypt, where both urothelial cell carcinoma (UC) and squamous cell carcinoma (SCC) types are highly prevalent. We used logistic regression to estimate the unadjusted (OR) and adjusted odds ratio (AOR) and 95% confidence interval (CI) of the associations between gender and different histopathologic and sociodemographic parameters of 2,186 confirmed cases of primary bladder cancer (1,775 males and 411 females; 784 SCC and 1,402 UC). There were no statistically significant gender differences in tumor grade, stage, mucosal ulcer, or inflammatory cystitis, regardless of the cancer type, but men were less likely than women to have undergone cystectomy with pelvic lymphadenectomy. Having Schistosoma haematobium (SH) ova in the bladder tissue was significantly associated with male gender in the fully adjusted model of either SCC (AOR (95% CI) = 2.12 (1.15–3.89)) or UC cases (3.78 (1.89–7.55)). Compared to females, male cases were significantly older at time of diagnosis and smokers. In Egypt, regardless of the type of bladder cancer (SCC or UC), male more than female cases had evidence of SH infection, but not other histopathologic differences, in bladder tissue specimens.
Worldwide, the incidence and prevalence of urinary bladder cancer are higher in men than in women , whereas several studies, reviewed by Fajkovic et al., have shown worse outcomes after radical cystectomy in the latter than in the former . Indeed, to predict recurrence of bladder cancer after surgery, the International Bladder Cancer Nomogram Consortium (IBCNC) developed a tool that includes, among other variables, sex, cancer histological type, and characteristics, as prognostic factors . However, Welty et al. developed a nomogram to predict survival after cystectomy for urothelial cell carcinoma, but did not include sex, because they found age and tumor stage to be considerably stronger risk factors than sex in predicting patient survival .
The present investigation used data collected on primary urinary bladder cancer in Egypt for the parent study, a multicenter case-control type that was conducted between 2006 and 2014. It was approved by the institutional review boards of the three collaborating cancer centers in Egypt: the University of Maryland in Baltimore MD, Georgetown University in Washington DC, and the National Scientific and Research Ethical Committee at the Egyptian Ministry of Health and Population.
From July 2006 through July 2014, 4,049 patients presumed to have bladder cancer were asked to participate in the study. Of those patients, 3,427 were eligible and 2,891 (84%) agreed to participate. The pathologists completed a review of 2,523 cases and confirmed 2,325 to be primary bladder cancer. There were 1,402 UC (60.3%), 784 SCC (33.7%), 77 adenocarcinomas (3.3%), and 62 (2.7%) cases of other types of primary bladder cancer.
We found male, more than female, cases of bladder cancer to have evidence of SH infection in their bladder tissue specimen, regardless of the type of cancer. These findings support our previous studies demonstrating that the self-reported history of SH infection is a risk factor, not only for SCC but also for the UC cancer type [26, 28]. Indeed, more men (55%) than women (20%) reported a history of schistosomiasis, and the pathologists reported more men (73% and 59% for SCC and UC, resp.) than women (53% and 42% for SCC and UC, resp.) to have SH ova in their bladder tissue specimens. The higher prevalence of SH infection in males, as compared to female cancer cases, can be explained by the fact that the majority of men worked in farming and thus were at risk for SH infection because of exposures to infested waters, while the majority of women did not work outside the house .
We found evidence for bladder tissue infection with SH to be significantly more prevalent in male than in female cases of bladder cancer, regardless of the type of cancer (SCC or UC); but there are no significant gender differences in other histopathological characteristics of either UC or SCC in Egypt. More studies are needed to elucidate the mechanism(s) underlying gender difference in bladder cancer.