Quantification of fibrinogen-to-pre-albumin ratio provides an integrating parameter for differential diagnosis and risk stratification of early-stage colorectal cancer
Authors: Ying Hou-Qun , Chen Wei , Xiong Cui-Fen , Wang Yuanyuan , Li Xiao-Juan , Cheng Xue-Xin 
Published: March 2022

Abstract
Background
Circulating fibrinogen to pre-albumin ratio (FPR) and albumin to fibrinogen ratio (AFR) are effective factors for predicting the prognosis of colorectal cancer (CRC). However, the role of these two ratios in diagnosing early-stage CRC and identifying the stage II CRC subgroup with high relapse risk remains unknown. This study aimed to assess the potential of FPR and AFR in differential diagnosis and risk stratification of early-stage CRC.

Methods
A discovery (694 and 512 patients with benign colorectal polyps and stage I–II CRC, respectively) and validation (201 benign colorectal polyps cases and 202 stage I–II CRC individuals) cohorts were enrolled in this study. Receiver operating characteristic curve (ROC), Kaplan–Meier curve, and time-dependent ROC were used to evaluate the diagnostic efficacy of AFR and FPR in the two cohorts and overall population, and the discriminating role of FPR in identifying clinical high-relapse risk patients in comparison with common clinical characteristics in stage II CRC patients.

Results
The area under the curve (AUC) of the preoperative circulating FPR was higher than that of AFR in the diagnosis of stage I–II CRC from colorectal adenomas and benign colorectal polyps in the discovery and validation cohorts and overall population. Carcinoembryonic antigen (CEA) combined with FPR could effectively discriminate early-stage CRC from colorectal adenomas or benign polyps. Preoperative FPR could effectively distinguish stage II subgroups with high and low relapse risk. It was superior to common clinical characteristics in identifying high-risk surgical patients who could benefit from adjuvant chemotherapy (CT) [time-dependent AUC: 0.637 vs. 0.511, p < 0.001 for predicting recurrence-free survival (RFS); 0.719 vs. 0.501, p < 0.001 for predicting overall survival (OS)]. Furthermore, CT treated stage II patients with FPR > 20 had the highest recurrence (31.16%) and death rates (21.88%), with similar highest recurrence (30.70%) and death (26.82%) rates found in non-CT-treated patients with FPR > 20. Stage II CRC patients with 20 ≥ FPR > 15 could significantly benefit from postoperative CT, as the recurrence (33.30%) and death (35.71%) rates within non-CT treated patients were approximately five times higher than those of the CT-treated cases (6.77% and 7.41% for the recurrence and death rates, respectively). No significant difference in recurrence rate was observed between L-FPR (≤ 15) patients with (10.00%) or without CT (9.76%), indicating that these patients might not require to receive adjuvant CT after curative resection.

Conclusions
Preoperative FPR combined with CEA is superior to common tumor biomarkers, FPR, or AFR in distinguishing early-stage CRC from benign colorectal polyps. Circulating FPR can be an effective biomarker for identifying high-risk patients and choosing suitable therapeutics for early-stage CRC.