Factors Associated with a Higher Rate of Pathological Complete Response After Long-Course Neoadjuvant Treatment for Locally Advanced Rectal Cancer Patients – Results from a Retrospective Cohort Study Focused On Inflammatory Indices

Pathologic complete response (pCR) after neoadjuvant chemoradiotherapy (NCRT) has a prognostic value in locally advanced rectal cancer (LARC). This study aimed to evaluate the ability to predict pCR using inflammatory markers, facilitating the selection of the optimal treatment strategy. Methods: Patients undergoing primary tumor resection after long-cycle NCRT at a single center (2012 to 2018) were retrospectively collected (n=130). Patient demographics, preoperative laboratory measurements, tumor characteristics, treatment strategy, and postoperative anatomopathological variables were collected. The association of factors to pCR was examined using binary logistic regression, odds ratio (OR) (95% confidence interval), and the discriminative capacity with the ROC curve. Results: Out of 130 patients, 42 pCRs occurred, equal to 32.3% of the sample. Variables identified as useful to predict pCR were total neutrophil count (<6400 cells/mm3; o‎r 7.6), intravenous 5-FU chemotherapy strategy (OR 3.2), and absence of diabetes (OR 3.4). Patients having all three of them had a 55.3% chance of pCR. Conclusion: The absolute neutrophil count better predicts pCR than other inflammatory indices in selected patients with LARC undergoing long-cycle NCRT. A neutrophil count less than 6400 cells/mm3, absence of diabetes, and intravenous 5-FU NCRT therapy lead to a relative rise in pCR.