Trends in incidence and survival of the four most common cancers by stage at diagnosis in Cyprus: A population-based study from 2004 to 2017.

Background: Breast, colorectal, lung and prostate cancers are the most frequent malignancies in Cyprus. This study estimated the incidence rate and 5-year net survival (NS) trends for these cancers, by sex, age, and tumor stage at diagnosis.

Methods: We analyzed data from the Cyprus Cancer Registry for adults diagnosed between 2004 and 2017, with follow-up until 2019. Tumor stage was classified into localized, regional, distant and unknown categories. We estimated the annual percentage change (APC) in incidence rates using Joinpoint regression. NS was estimated using flexible parametric models, adjusting for sex, age, stage and period of diagnosis. Multiple imputation was used to address unknown cancer stage.

Results: During 2004-2017, the incidence significantly increased for breast and lung cancer (APC: 1.1 % and 2.6 %, respectively), mainly among the elderly (70 +). A decreasing trend was identified for prostate cancer only among individuals aged 80 +. No temporal variations were identified for colorectal cancer incidence. A positive time trend was identified for localized breast cancer between 2006 and 2017 (APC: 2.8 %). Conversely, a significant increase was noted at more advanced stages for lung (APC: 4.1 %) and prostate (APC: 7.6 %) cancers. NS improved for all cancers, ranging between 80 % and 90 % for regional and all stages of breast cancer, localized colorectal cancer, and all stages of prostate cancer, surpassing 95 % for localized breast cancer, localized and regional prostate cancer.

Conclusion: The study observed increased (breast and lung) or stable (colorectal and prostate) cancer incidence and substantial improvements in 5-years NS trends for all cancer types, despite differences by sex and stage. Efforts should be intensified to reduce incidence by addressing cancer risk factors, and to improve survival by implementing and increasing the uptake of screening programs.