Bladder cancer is a common urinary malignant tumor. In 2012, bladder cancer ranks as the ninth most common‐diagnosed cancer with estimated 430,000 new cases. For the past few years, the overall incidence and mortality of bladder cancer have shown a positive trend and become a serious threat for the global health. Risk factors for bladder cancer include smoking, family history, prior radiation therapy, frequent bladder infections especially due to parasites and exposure to certain industrial chemicals. Tobacco smoking is the main known contributor to urinary bladder cancer; in most populations, smoking is associated with over half of bladder cancer cases in men and one-third of cases among women. However, these proportions have reduced over recent years since there are fewer smokers in Europe and North America. There is an almost linear relationship between smoking duration (in years), pack years and bladder cancer risk. A risk plateau at smoking about 15 cigarettes a day can be observed (meaning that those who smoke 15 cigarettes a day are approximately at the same risk as those smoking 30 cigarettes a day).
Quitting smoking reduces the risk, however former smokers will most likely always be at a higher risk of bladder cancer compared to people who have never smoked. Passive smoking does not appear to be a risk. Early menopause increases the risk of bladder cancer for smokers – this was the finding of an interdisciplinary research group, using data from 230,000 participants in the longitudinal Nurses’ Health Studies I and II. Hormonal factors have no influence on the incidence of the disease but smokers who start the menopause before the age of 45 run a more than 50% higher risk of developing it. The results of the, as yet unpublished, study were recently presented at the European Association of Urology (EAU) Congress in Barcelona. In Austria, approximately 1,600 people a year develop bladder cancer, men being approximately four times more likely to be affected than women. That said, the mortality rate is around 40% higher in women. The reasons for this gender difference are unclear.
The original question of the study conducted by a research group led by urologist Mohammad Abufaraj from Department of Urology and researchers from the Division of Epidemiology at MedUni Vienna’s Center for Public Health, and scientists from Harvard Medical School and other hospitals was to establish the significant risk factors for women. The team explored whether hormonal processes in the female body play a role in the development of bladder cancer. To do this they analyzed data from the Nurses’ Health Study 1 and 2 (NHS I and II). The Nurses’ Health Study is the largest women’s health study in the world and has produced important findings relating to nutrition and cancer risks by means of questionnaires and clinical examinations of women. Initially, nurses were explicitly invited to participate, since they have an above-average level of medical knowledge. The participants are surveyed every two years about contraception, diet and lifestyle habits.
Over the observation period, the study team has now found 629 cases of bladder cancer and compared the data of women who started the menopause after the age of 50 with those of women who started the change before the age of 45. What stood out was that women who had an early menopause were more likely to have developed bladder cancer. It was statistically determined that women who smoked – who often experience an early menopause as a result of smoking – have a 53% higher risk of developing this type of cancer. Data also showed that factors such as the age when period began, the number of pregnancies, use of oral contraceptives or hormone replacement therapy do not increase the risk of bladder cancer. Besided EAU, the 16th Meeting of the International Bladder Cancer Network (IBCN) took place from October 11-13, 2018 in Rotterdam, the Netherlands. A take home message of the meeting was that the IBCN increasingly serves as an interdisciplinary forum not for the presentation of work-in-progress covering all facets of bladder cancer research, but also for catalyzing the discussion of discrepant research findings in an effort to find consensus.
- Edited by Dr. Gianfrancesco Cormaci, PhD, specialist in Clinical Biochemistry.
Scientific references
Mun DH et al., Abufaraj M. Curr Opin Urol. 2019; 29(3).
Su H, Jiang H, Tao T et al. Cancer Med. 2019 Mar 24.
Adjei Boakye E, Piccirillo JF. Int J Cancer. 2019 Jan 6.
Cumberbatch MG et al. Eur Urol. 2018; 74(6):784-795.