Impact of Screening Programs on Stage Migration in Breast Cancer.

Introduction: Breast cancer (BC) is the leading malignancy globally with consequent morbidity, mortality and burden on health care resources when diagnosed at an advance stage. Early-stage diagnosis is crucial to the better outcome. Screening is pivotal to early detection at an early stage. It is understood to reduce mortality, improve outcome, and is cost effective.

Objective: The objective of the study was to see the impact of screening program on Breast cancer stage in Oman. In this study we looked into the trends in stagespecific breast cancer incidence during two pre-specified time periods 2006-2010 and 2015-2017, before and after the introduction of a national screening programme in Oman.

Patients and methods: It is a retrospective analysis, where breast cancer patient's data was retrieved from Oman national cancer Registry ministry of health Sultanate of Oman, for two pre-specified time periods 2006-2010 before the introduction of cancer screening programs and 2015-2017. The cases included were those who had confirmed histopathology diagnosis and where a composite stage, based on TNM stage, was available to be analysed and compared in these two pre-specified time periods to find out the difference between these two time periods. The statistical analysis was carried out and p values were determined. Ethical approval obtained from Royal Hospital medical ethics and scientific research committee.

Results: There was a 41% reduction in stage IV breast cancer from 23.01% to 13.58 %, and 86.15% increase in stage 0-1 from 6.86 % to 16.98%. (p Value<001). The stage 0 cases increased from 0% to 4.26 %. With regard to tumour size, T0-1 tumours increased from 14.16% to 26.03%, while T4 tumours decreased from 16.59% to 7.69%. There was increase in node negative breast cancer cases in Oman. The N0 increased from 28.43% to 37.64%. The diagnosis as Non-metastatic M0 disease increased from 39.77% to 60.23%, while diagnosis as metastatic M1 disease decreased from 55.32% to 44.68%.

Discussion and conclusions: The introduction of national screening programme in Oman resulted in a continued increase in localized cancers and a decline in advanced disease. Screening programmes should be evaluated continuously and systematically to ensure their targeted objectives. The causal link between stage distribution and mortality needs to be investigated further in the context of screening. Health planners, policymakers, and other stakeholders; including clinicians, educators, community members, and advocates, should be aware of the health system requirements, as well as overall costs of these approaches to breast cancer early detection, to make effective investments, plans, and policies. Key Words: Breast Cancer; Screening; Oman; Royal hospital; early detection; early stage; OCA.