In rectal cancer surgery, the organ/space surgical site infection (O/S-SSI) has an impact on patient's prognosis. Its influence in the oncologic outcomes remains controversial. The main objective is to assess the possible effect of O/S-SSI on long-term overall survival and cancer recurrence.

Colorectal cancer is the third most common malignancy worldwide and the fourth leading cause of cancer death in both sexes, accounting for 30-35% of all tumours originating in the rectum. Although the introduction of total mesorectal excision and the use of neoadjuvant chemoradiation have improved the oncological outcome in patients with rectal cancer operated with curative intent, the 5-year recurrence rate remains around 20%, with tumour stage being the most important prognostic factor. Other tumour-related factors, such as lymphovascular, perineural and extramural vascular invasion, as well as response to neoadjuvant treatment, have also been shown to be reliable predictors of recurrence. However, surgery-related factors, such as the quality of surgical resection as well as the occurrence of postoperative complications, may have a profound impact on these outcomes.

Anastomotic leakage is one of the most serious complications of colorectal surgery and its frequency ranges from 3 to 21% depending on the location of the tumour and the definition of anastomotic leakage used. This complication is associated with considerable morbidity and mortality and may affect quality of life. Several studies have shown that anastomotic leakage and subsequent organ-space infection (O/S-SSI) are also associated with higher rates of tumour recurrence and cancer-specific mortality. A recent meta-analysis involving 43 studies with a total of 154,981 patients undergoing colorectal cancer surgery found that postoperative O/S-SSI and anastomotic leakage had a significant negative impact on disease-free survival, local recurrence and overall recurrence. This association has also been reported after resection of liver metastases and other gastrointestinal malignancies. In addition, the severity of postoperative infection has also been correlated with increased risk of recurrence.

However, these results have not been confirmed in other studies. In our setting, the development of anastomotic leaks did not affect the risk of local recurrence, overall recurrence, overall survival or cancer-specific survival in a multicentre observational study using prospectively collected data from 1181 consecutive rectal cancer patients in 22 hospitals included in the Spanish Rectal Cancer Project. These results were consistent with data reported by national colorectal cancer registries such as those of Denmark and Sweden, among others. Therefore, the question of whether anastomotic leakage contributes to disease recurrence remains controversial and requires further research.

In an attempt to clarify this controversy, a population-based study was conducted to assess the influence of O/S-SSI on recurrence and survival outcomes in patients who had undergone curative surgery for rectal cancer in hospitals integrated in the Public Health System of Catalonia (Spain) at 5-year follow-up.

Inclusion Criteria:

• Patients > 18 years old
• Eligible patients with tumour ≤ 13 cm from anal verge, as measured by Magnetic Resonance Imaging
• Primary adenocarcinoma
• Oncological resection with curative intent
• Cancer stages: I-II-III

Exclusion Criteria:

• Transanal local resection
• Emergency colorectal surgeries
• Presence of metastases found in the diagnostic process or during the surgical procedure
• Recurrence of the disease treated before the study period
• Non-resectable tumour or palliative surgery
• Patients operated in private centres

Patients operated on rectal surgery for rectal cancer in Catalonia, Spain.

Restrictions apply to the availability of these data, which belong to two national databases and are not publicly available. Data was obtained from the Catalan Cancer Plan and VINCat, and are only available with the permission of their Technical Committees.