While cancer is the third leading cause of mortality in Iran (9), few epidemiological studies are available regarding this problem in the country. In this population-based study, we used data from Iran’s Ministry of Health to present the most recent trends of bladder cancer incidence in the country and its provinces from 2003 to 2015.
The results showed that incidence rate of bladder cancer is higher in men as only 17.8% of all bladder cancers occurred in women. This is similar to global numbers where approximately 23% of new cases of bladder cancer are females (1).
We showed that ASR of bladder cancer increased from 8.35 in 2003 to 13.57 in 2015 in men. ASR of bladder cancer also showed a mild increase in females (2.12 in 2003 versus 2.86 in 2015), which indicate that the rise of bladder cancer ASR in men (63%) has been much higher than in women (35%) through the years of the study. In 2013, ASR of bladder cancer among Iranian males and females was 11.76 and 2.17, respectively, showing a drastically lower incidence than that of developed countries (23.59 and 4.82 in males and females, respectively), but comparable to global average (11.81 in men and 2.69 in women) (10). On the other hand, while ASR of bladder cancer incidence in Iran has increased in years 2003 to 2015 among both men and women, it has declined globally from 1990 to 2016 (1). This trend is observed in both developed and developing countries (10).
Our results show that incidence of bladder cancer is higher in older population. Iranian males and females have life expectancies of 81.6 and 71.6, respectively, which have been increasing constantly through the last 40 years (11). If the trend continues, the incidence rate of bladder cancer increases may increase further due to aging of the population.
Analyzing geographical distribution of new bladder cancer cases indicated that Bushehr province presented the highest ASR in females in 2015 (6.83), while the highest ASR in males in the same year was observed in Kerman province (22.40).
Iran is a developing country and as mentioned previously, its population is getting older. Therefore, bladder cancer incidence is likely to rise, as older age groups are more likely to be diagnosed with bladder cancer. Moreover, higher age might worsen the complications and burden of the disease. However, some important risk factors of bladder cancer such as smoking (12) are modifiable and the importance of educational and preventive strategies cannot be overstated. Inequality in health resource allocation may also contributes to varying incidence rates in different provinces.