UNIT OF MEASUREMENT: Cumulative incidence of patients with locally recurrent rectal cancer in curatively treated primary rectal cancer patients MEASUREMENT TOOL: Registration of diagnosis of locally recurrent rectal cancer in the electronic patient file.

The competing-risk cumulative incidence will be calculated, which will inform on the proportion of patients who have developed locally recurrent rectal cancer at that time point.

UNIT OF MEASUREMENT: Risk factors for development of locally recurrent rectal cancer in primary rectal cancer patients MEASUREMENT TOOL: Registration of clinical and pathological covariates of primary rectal cancer in the electronic patient file and national pathological database (PALGA).

Clinical and pathological risk factors for the development of locally recurrent rectal cancer will be identified using multivariable competing-risk risk regression analyses, according to the cause-specific hazard approach. This will inform on specific clinical and pathological covariates which increase or decrease the risk for development of locally recurrent rectal cancer.

UNIT OF MEASUREMENT: Proportions of treatment given to patients with locally recurrent rectal cancer; MEASUREMENT TOOL: Registration of treatment for locally recurrent rectal cancer in the electronic patient file.

Using descriptive statistics, treatment patterns of patients with locally recurrent rectal cancer will be identified. Groups that will be created, will also be used to assess overall survival.

UNIT OF MEASUREMENT: Overall survival of patients with locally recurrent rectal cancer; MEASUREMENT TOOL: Registration of vital status in the national personal records database.

Overall survival will be estimated for patients with locally recurrent rectal cancer, stratifying for different groups (i.e. treatment, diagnosis of synchronous metastases, diagnosis within first year after primary resection, etc.)