[Epidemiological characteristics of incidence rate for breast cancer in Qidong City, 1972-2021].

Objective: To describe the epidemiological characteristics of breast cancer incidence in Qidong City between 1972 and 2021, and provide guidelines for preventive and control measures and strategies. Methods: The cancer registry data were collected and breast cancer incidences during 1972 and 2021 in Qidong by sex, age, and time were analyzed. Crude incidence rate (CR), China age-standardized rate (ASRC), world age-standardized rate (ASRW), annual percentage change (APC), and average annual percentage change (AAPC) were calculated by Joinpoint software. The age-period-cohort model was used to analyze the influence of age, period, and birth cohort on the changes in the incidence trend of breast cancer. Results: From 1972 to 2021, there were 6 929 patients with breast cancer in Qidong, accounting for 4.70% of all new cancer cases, with a CR of 12.35/10⁵, a ASRC of 6.63/10⁵, and a ASRW of 8.89/10⁵. The truncated incidence rate among people aged 35-64 years was 21.90/10⁵. The cumulative incidence rate of the ages between 0 and 74 years was 0.96%. The cumulative risk was 0.96%. There were 98 male patients, whose CR, ASRC, and ASRW were 0.35/10⁵, 0.17/10⁵, and 0.25/10⁵, respectively. The number of female patients was 6 831, and the CR, ASRC, and ASRW were 24.02/10⁵, 12.86/10⁵, and 17.13/10⁵, respectively. The AAPC of ASRW of female breast cancer was 3.45% (95% CI: 2.90%-4.01%). The increasing trend of the incidence rate was statistically significant (P＜0.05). The AAPCs of females aged 25-34, 35-44, 45-54, 55-64, 65-74, and ≥75 years were 2.78% (95% CI: 0.88%-4.72%), 2.20% (95% CI: 0.83%-3.60%), 3.81% (95% CI: 2.45%-5.19%), 4.48% (95% CI: 3.12%-5.85%), 3.79% (95% CI: 2.19%-5.43%), and 2.87% (95% CI: 1.14%-4.63%). The increasing trends of the incidence rates in all age groups were statistically significant (P＜0.05). The age-period-cohort model showed that the risk of breast cancer increased with age, and people born later were faced with a higher risk of the disease (P＜0.05). Conclusion: The incidence of breast cancer presented a rising trend in the past fifty years in Qidong. The increasing trend of the incidence rate was statistically significant since the beginning of this century. The health administrative department should formulate preventive and control measures to reduce the burden of breast cancer.