DataBase for Analysis of Rectal Cancer Oncological Results

The data will be obtained from 10 tertiary centers located in Poland (Cracow - coordinating center, Warsaw - 3 centers, Sosnowiec, Szczecin, Bydgoszcz, Lublin, Gdansk, Poznan) and 5 foreign centers. The analyses will include patients with rectal cancer operated on between 2013-2019. A database in MS Excel is prepared that consists of following data: * Type of neoadjuvant treatment (if any) * Time-interval between the end of neoadjuvant treatment and surgery * Type of surgery * Staging of rectal cancer i.e. (y)pTNM * Number of retrieved lymph nodes * Number of lymph nodes with metastases * R classification (R0, R1, R2) * Preoperative medications (metformin, statins, NSAIDs, anticoagulants) * Recurrence date and type (local, systemic, both diagnosed at the same time) * Date of death or date of last follow-up visit The aims of the study are following: 1. Establishing whether neoadjuvant treatment (PSCR or chemoradiotherapy) influences number of retrieved lymph nodes in rectal cancer 2. Establishing whether time-interval between the end of PSCR and surgery influences lymph node yield 3. Establishing the prognostic value of lymph node ratio - validation of the previously calculated cutoff point at the level of 0.41 4. Determining independent prognostic factors in rectal cancer - in particular related to medications taken before the operation, metformin and anti diabetic drugs in the first place

Sex

All

Minimum age

18 Years

Inclusion Criteria:

* Primary rectal cancer confirmed histologically
* Age ≥ 18

Exclusion Criteria:

* Recurrent rectal cancer
* Oncological radicalization after previous local excision of rectal cancer