Changing patterns and potential overdiagnosis of major screened cancers in Pudong New Area of Shanghai

Objective To investigate the potential overdiagnosis of major screened cancers at the population level by comparing secular trends of incidence and mortality based on cancer surveillance data. Methods Data on the incidence and mortality of cancers of lung, thyroid cancer, female breast cancer, colorectal cancer, gastric cancer, liver cancer, esophageal cancer, prostate cancer, and cervical cancer were extracted from the Shanghai Pudong New Area cancer registry and cause-of-death registration system during January 1, 2002 and December 31, 2019. The age-standardized incidence rates, mortality rates, and stage-specific (Stage I to IV) incidence rates were calculated separately for males and females according to the year of diagnosis or death. Joinpoint regression was used to calculate the segmented annual percentage change(APC), the average annual percent change(AAPC), and their 95%CI for the standardized rates. Results Three changing patterns in age-standardized incidence and mortality were observed for the nine cancers. The first pattern was characterized with significant increases in both incidence and mortality. The pattern was mainly observed for prostate cancer, cervical cancer, and male colorectal cancer, with an AAPC ranging from 1.78% to 6.39% for incidence and from 1.61% to 5.78% for mortality. The second pattern with significantly decreased incidence and mortality was found for gastric cancer, liver cancer and esophageal cancer, with an AAPC of -6.63% to -3.13% for incidence and -7.01% to - 3.56% for mortality. The third pattern manifested as significant increased incidence accompanying by decreased or stable mortality, which was observed for thyroid cancer, lung cancer, and female breast cancer. The APC(95%CI) of thyroid cancer incidence during 2002 and 2019 was 19.72% (17.75% to 21.72%) in men and 17.19% (15.27% to 19.14%) in women, whereas the AAPC(95%CI) of thyroid cancer mortality was 3.83%(-1.73% to 9.71%) in men and 2.76% (-1.51% to 8.01%) in women. For female breast cancer, the AAPC(95%CI) was 1.74%(1.17% to 2.45%) for incidence and 0.66% (-0.15% to 1.50%) for mortality. Regarding lung cancer, the incidence in men decreased from 56.21 per 100000 in 2002 to 48.77 per 100000 in 2009, and thereafter increased with an APC of 2.03% (95% CI: 0.85% to 5.59%); the incidence in women increased 13.44%(95%CI: 11.72% to 15.20%) per year since 2012. In comparison, the lung cancer mortality significantly declined during 2002 and 2019, with an AAPC(95%CI) of -1.75%(-2.29% to -1.15%) in men and -1.59%(-2.29% to -0.88%) in women. The incidences of stage-I thyroid cancer, female lung cancer and female breast cancer increased significantly during the period, while those of late-stage cancers remained stable. Conclusions Overdiagnosis may exist in thyroid cancer, female lung cancer and female breast cancers in Pudong New Area of Shanghai. Further studies are needed to confirm our results and quantify the overdiagnosis in the populations. © 2025 Chinese Journal of Cancer Prevention and Treatment, Editorial board. All rights reserved.