Development and validation of postoperative and preoperative platelets ratio (PPR) to predict the prognosis of patients undergoing surgery for colorectal cancer: A dual-center retrospective cohort study

Abstract

Background: Platelets occupy a prominent place in tumor proliferation and metastasis, and platelet count is relevant to the prognosis of tumor patients. But preoperative platelet counts cannot be standardized and individualized due to the variability among individuals, instruments, and regions, and the connection between postoperative platelet count and prognosis remains unknown. A standardized indicator of platelet count was designed to forecast the prognosis of colorectal cancer (CRC).

Methods: Five hundred and eighty six patients who suffered radical resection of CRC between 2013 and 2019 were collected. A development-validation cohort of standardized and individualized platelet counts for prognostic assessment of CRC was designed. We first determined the ability of PPR and other peripheral blood count-related indicators to predict the mortality of patients with CRC and validated them in a separate cohort. Kaplan-Meier analysis was executed to evaluate the survival and univariate and multivariate analyses were executed to explore the relevance. Time-dependent ROC was measured to estimate the predictive usefulness. Decision curve analysis was used to verify the clinical net benefit.

Results: Important baseline variables showed a similar distribution in two independent queues. In the development cohort, postoperative platelet count and postoperative/preoperative platelets ratio (PPR) were independent predictors of prognosis in CRC patients. PPR showed the largest area under the curve (AUC) in evaluating 1-year and 5-year OS (AUC: 0.702 and 0.620) compared to others. In the validation cohort, platelet/lymphocyte ratio and PPR were validated to be independently concerned about OS of CRC patients and PPR showed the largest AUC in evaluating 1-year and 3-year OS (AUC: 0.663 and 0.673). PPR and joint index of platelet count and PPR showed better predictive value and clinical net benefit.

Conclusions: PPR has been identified and validated to be independently concerned about OS of patients with CRC and was a reliable and economic indicator to evaluate the prognosis.

Keywords: colorectal cancer; postoperative and preoperative platelets ratio; preoperative platelet count; prognosis; validation.