It is generally recognized that cigarette smoking is the most important risk factor for bladder cancer. A recent study was undertaken to examine the relationships between smoking history of bladder cancer patients and the age of onset of bladder cancer and tumor characteristics.

The study examined the data for 5959 cases (4728 males and 1231 females) collected in the bladder cancer database of the Japanese Urological Association from 1999 to 2001.

Patients were divided by smoking history into three categories as current non-smokers, current smokers and unknown smoking history. Relationship between smoking history and the age at diagnosis of bladder cancer, gender, T stage, grade, tumor size, tumor number and initial symptoms was analyzed.

In both males and females the onset of bladder cancer is about 6 years (6.1 years in males and 5.9 years in females) earlier for current smokers than for current non-smokers. At the time of diagnosis, tumor stage was significantly higher in the current smokers group. The current smokers group tended to have larger tumor size.

The finding of 6-year-earlier onset of bladder cancer among current smokers is of great importance to both health care and medical economics. It is essential to make people better informed concerning the need to quit smoking.

In an earlier study the relationship between smoking and bladder cancer risk was investigated using data from a case-control study conducted between January 1994 and July 1996 in Alexandria, Egypt.

The results found a remarkably strong association with various measures of cigarette smoking that could explain 75% of bladder cancer cases among males from Alexandria. The prevalence of smoking was very low among women, and consequently tobacco was not a relevant risk factor for female bladder cancer.
References:
1. Hinotsu S, Akaza H, Miki T, Fujimoto H, Shinohara N, Kikuchi E, Mizutani Y, Koga H, Okajima E, Okuyama A; Japanese Urological Association. Bladder cancer develops 6 years earlier in current smokers: analysis of bladder cancer registry data collected by the cancer registration committee of the Japanese Urological Association. Int J Urol. 2009 Jan;16(1):64-9. PMID: 19054170.
2. Bedwani R, el-Khwsky F, Renganathan E, Braga C, Abu Seif HH, Abul Azm T, Zaki A, Franceschi S, Boffetta P, La Vecchia C. Epidemiology of bladder cancer in Alexandria, Egypt: tobacco smoking. Int J Cancer. 1997 Sep 26;73(1):64-7. PMID: 9334811.