Changes in spatial clusters of cancer incidence and mortality over 15 years in South Korea: Implication to cancer control.

BACKGROUND: The temporal investigation of high-risk areas of cancer incidence and mortality can provide practical implications in cancer control. We aimed to investigate the changes in spatial clusters of incidence and mortality from 1999 through 2013 by major cancer types in South Korea. METHODS: We applied flexible scan statistics to identify spatial clusters of cancer incidence and mortality by three 5-year periods and seven major cancer types using the counts of new cases and deaths and population in 244 districts during 1999-2013. Then, we compared the changes across three periods in the locations of primary clusters of incidence and mortality by cancer types. To explore the determinants that possibly affect cancer cluster areas, we compared geographic characteristics between clustered and non-clustered areas. RESULTS: While incidence clusters for lung, stomach, and liver cancer remained in the same areas over 15 years, mortality clusters were relocated to the areas similar to those of incidence clusters. In contrast, colorectal, breast, cervical, and prostate cancer displayed consistently different locations of clusters over time, indicating the disappearance of existing clusters and the appearance of new clusters. Cluster areas tended to show higher portions of older population, unemployment, smoking, and cancer screening compared to non-cluster areas particularly for mortality. CONCLUSIONS: Our findings of diverse patterns of changes in cancer incidence and mortality clusters over 15 years can indicate the degree of effectiveness in cancer prevention and treatment depending on the area and suggest the need for area-specific applications of different cancer control programs.

Changes in, and predictors of, quality of life among patients with unstable angina after percutaneous coronary intervention.

RATIONALE, AIMS AND OBJECTIVES: Changes in, and predictors of, quality of life (QoL) among unstable angina patients are informative for both clinical and public health practice. However, there is little research on this topic, especially in health care settings with limited resources. This study aims to detect changes in QoL and its associated factors among patients with unstable angina after percutaneous coronary intervention. METHODS: A longitudinal design was conducted with two repeated rounds of measurements, 1 and 3 months after intervention, using the generic SF-36 questionnaire, in 120 patients from Vietnam National Heart Institute. A linear mixed-effects model was used to assess changes in patient QoL over time while adjusting for other covariates. RESULTS: Only two out of eight QoL subscales (social functioning and emotional well-being) declined after 1 month, but these tended to rise again after 3 months, while scores of all other QoL subscales increased. Adjusting for covariates, QoL increased slightly after 1 month of intervention (ß = 0.65, 95%CI = -0.86 to 2.16) but improved by almost six QoL points after 3 months (ß = 5.99, 95%CI = 4.48 to 7.50). Four confounders significantly associated with a decline in QoL were older age, being retired, living in rural areas, and having abnormal troponin level. CONCLUSION: QoL of the patients with unstable angina improves significantly 3 months after intervention, rather than after 1 month. More attention should be given to patients, who are old, retired, live in rural areas and have abnormal troponin level.