Net survival differences of breast cancer between stages at diagnosis and age groups in the east coast region of West Malaysia: a retrospective cohort study

OBJECTIVE: Estimation of the net survival of breast cancer helps in assessing breast cancer burden at a population level. Thus, this study aims to estimate the net survival of breast cancer at different cancer staging and age at diagnosis in the east coast region of West Malaysia.

SETTING: Kelantan, Malaysia.

PARTICIPANTS: All breast cancer cases diagnosed in 2007 and 2011 identified from Kelantan Cancer Registry.

DESIGN: This retrospective cohort study used a relative survival approach to estimate the net survival of patients with breast cancer. Thus, two data were needed; breast cancer data from Kelantan Cancer Registry and general population mortality data for Kelantan population.

PRIMARY AND SECONDARY OUTCOME MEASURES: Net survival according to stage and age group at diagnosis at 1, 3 and 5 years following diagnosis.

RESULTS: The highest net survival was observed among stage I and II breast cancer cases, while the lowest net survival was observed among stage IV breast cancer cases. In term of age at diagnosis, breast cancer cases aged 65 and older had the best net survival compared with the other age groups.

CONCLUSION: The age at diagnosis had a minimal impact on the net survival compared with the stage at diagnosis. The finding of this study is applicable to other populations with similar breast cancer profile.