Trends in the Incidence and Mortality of the Most Common Cancers in Iraq (Iraqi Cancer Registry 1999-2019).

Cancer is the second leading cause of death in Iraq following heart and cerebrovascular diseases. Assessment of incidence and mortality trends is essential for prioritizing cancer control in the national health policies and plans.

Aim: To determine the patterns and trends in the incidence and mortality of the leading types of cancers affecting the Iraqi population during the last two decades.

Material and methods: This is a descriptive retrospective study based on the available data of the Iraqi Cancer Registry for the years (1999 - 2019). The analyzed information included the annual total number of new cancer cases and cancer deaths during the assigned period categorized by site, age, gender and morphology of each cancer. The data was coded according to Cancer Registry Program 4 (Can Reg4) and the International Classification of Diseases for Oncology (ICD-O). The estimated total annual number of Iraqi populations for the same period was retrieved from the Iraqi Ministry of Planning. The incidence and mortality rates were calculated per 100,000 Iraqi population and classified by ICD-O, site of the tumor, gender and age group.

Results: The overall cancer incidence rate (IR) in 2019 was 91.66/100,000 population (78.14 and 105.46/100,000 in males and females, respectively). The age standardized rate (ASR) was 155.60/100,000. The top five cancers in terms of IR were those of the breast (18.17/100,000; ASR:29.93/100,000), lung (7.24/100,000; ASR:14.81 /100,000), colorectum (5.95/100,000; ASR:10.77 /100,000), brain/CNS (5.83/100,000, ASR:8.39/100,000) and leukemia (5.05/100,000; ASR:6.83/100,000). The peak IR was observed among patients of both genders in the eighth decade of life (1127.37/100,000). The trend of IR for all cancers has significantly increased from 43.95/100,000 in 1999 to 91.66/100,000 in 2019 (more than 100%, p < 0.0001). The highest increase was demonstrated in cancers of the colorectum (from 1.2 to 5.90, p< 0.001), breast (from 6.6 to 18.2, p< 0.001) and brain (from 2.0 to 5.80, p=0.032). On the other hand, the mortality rate (MR) was 28/100,000 population in 2019 (28.45 and 27.55/100,000 in males and females, respectively). The highest MR was observed in cancers of the lung (4.48/100,000), breast (3.16/100,000) and leukemia (2.42/100,000). Whereas a non-significant increase in the mortality trends of leukemia, colorectum, breast and lung cancers were noted, our data revealed a decline in the trend of brain/CNS cancer mortality (from 3.2 to 2.3/100,000).

Conclusions: The top leading cancers in Iraq are steadily increasing in upward trends though they remain lower than the global rates. The underestimated IRs and MRs are possibly attributed to suboptimum registration and missing data due to the lack of a national surveillance system. Efforts should be directed to prioritize the adoption of the national cancer control plan focusing on strengthening the population-based cancer registry.

Key words: Trends, incidence; mortality, Iraq; common cancers.