Postoperative lymphopaenia as a risk factor for postoperative infections in cancer surgery: A prospective multicentre cohort study (the EVALYMPH study)

Background: Stress due to surgical trauma decreases postoperative lymphocyte counts (LCs), potentially favouring the occurrence of postoperative infections (PIs).

Objectives: We aimed to determine whether postoperative lymphopaenia following thoracic or gastrointestinal cancer surgery is an independent risk factor for PIs and to identify modifiable factors related to anaesthesia and surgical procedures that might affect its occurrence.

Study design: The EVALYMPH study was a prospective, multicentre cohort study with a 30-day patient follow-up. Multivariate analyses were performed to determine the risk factors for PIs and for postoperative lymphopaenia.

Setting: Patients were included from January 2016 to September 2017 in 25 French centres.

Patients: Adult patients admitted for thoracic or gastrointestinal cancer surgery were eligible for inclusion.

Main outcome measure: PIs within 30 days after surgery were defined as urinary tract infections, pneumonia, surgical site infections and other infections (bloodstream infections or pleurisy).

Results: Of 1207 patients included, 273 (22.6%) developed at least one infection within 30 days after surgery, with a median [IQR] time to onset of 8 [5 to 11] days. An increased risk of PI was significantly associated with an ASA score of IV: hazard ratio (HR) 4.27 (95% confidence interval (CI), 1.87 to 9.72), surgery > 200 min (HR 1.58 (1.15 to 2.17) and lymphopaenia on postoperative day 1 (POD1) (HR 1.56 (1.08 to 2.25). This risk was associated with changes in postoperative LC over time (P = 0.001) but not with preoperative LC (P = 0.536).POD1 lymphopenia was related to patient characteristics and duration of surgery but not to potentially modifiable other surgical or anaesthetics factors.

Conclusions: POD1 lymphopaenia was associated with PIs in patients undergoing thoracic or gastrointestinal cancer surgery. To individualise care, patient characteristics and surgery duration should be taken into account.

Trial registration: ClinicalTrials.gov Identifier: NCT02799251.