Evaluation of observed and the expected incidence of common cancers: An experience from Southwestern of Iran, 2010–2014

Background: Awareness of observed and expected incidence of cancers is so important in managing cancer as the third mortality cause in Iran. In the present study, we evaluated observed and the expected incidence of common cancers in Chaharmahal and Bakhtiari province. Materials and Methods: This study is a Secondary data analysis. All data about pathology‑based cancer registration (Cancer diagnosis was based on pathological laboratory, ICD‑O2) in Chaharmahal and Bakhtiari in Southwestern Iran in 2010–2014 was used. By dividing the number of registered cases of each cancer in every age group into the total observed cancers in that age group, the observed ratio of each cancer in that age group was calculated. Then, using the proposed coefficients Parkin and age‑standardized cancer ratio method, the expected ratios in each age group, were calculated. Results: In 5 years study, 2918 new cases of cancer were recorded. Out of them, 1735 (59.46%) were male. The annual average total occurrence of all cancers in this province was 68.2/100,000 populations. The observed incidence ratios of common cancers, including stomach, breast, colorectal, thyroid, lymph nodes, ovaries, gall bladder, the bladder and the brain, were 0.11, 0.12, 0.09, 0.06, 0.02, 0.03, 0.01, 0.08, and 0.05, respectively. The expected incidence ratios of above‑mentioned cancers are 0.11, 0.13, 0.1, 0.06, 0.02, 0.03, 0.01, 0.08, and 0.05, respectively. Based on observed (O) and expected (E) comparison, breast and colorectal cancer had higher incidence than expected ratio. Conclusion: Our results showed that in our area, treatment programs and health plans should focus on cancer registration, especially on common cancers and reevaluate breast and colorectal cancer occurrence. Therefore, the plan for the control and prevention of this cancer must be a high priority for health policymakers.