IMMUNOREACT 0: Biopsy-based immune biomarkers as predictors of response to neoadjuvant therapy for rectal cancer-A systematic review and meta-analysis

Compare clinical efficacy and safety of neoadjuvant therapy and neoadjuvant chemoradiotherapy for locally advanced rectal cancer: Meta-analysis

BACKGROUND

To compare the efficacy and safety of total neoadjuvant therapy (TNT) and neoadjuvant chemoradiotherapy (nCRT) in the treatment of middle and low locally advanced rectal cancer. Our study will systematically collect and integrate studies to evaluate the ability of these two treatments to improve tumor shrinkage rates, surgical resection rates, tumor-free survival, and severe adverse events.

AIM

To provide clinicians and patients with more reliable treatment options to optimize treatment outcomes and quality of life for patients with locally advanced rectal cancer by comparing the advantages and disadvantages of the two treatment options.

METHODS

A full search of all clinical studies on the effectiveness and safety of TNT and nCRT for treating locally advanced rectal cancer identified in Chinese (CNKI, Wanfang, China Biomedical Literature Database) and English (PubMed, Embase) databases was performed. Two system assessors independently screened the studies according to the inclusion and exclusion criteria. Quality evaluation and data extraction were performed for the included literature. We used RevMan 5.3 software to perform a meta-analysis of the pathologic complete response (pCR) rate, T stage degradation rate, resection 0 (R0) rate, anal grade 3/4 acute toxicity rate, perioperative complications, overall survival (OS), and disease-free survival (DFS) in the TNT and nCRT groups.

RESULTS

Finally, 14 studies were included, six of which were randomized controlled studies. A total of 3797 patients were included, including 1865 in the TNT group and 1932 in the nCRT group. The two sets of baseline data were comparable. The results of the meta-analysis showed that the pCR rate [odds ratio (OR) = 1.57, 95% confidence interval (CI): 1.30-1.90, P < 0.00001], T stage degradation rate (OR = 2.16, 95%CI: 1.63-2.57, P < 0.00001), and R0 resection rate (OR = 1.42, 95%CI: 1.09-1.85, P = 0.009) were significantly greater in the nCRT group than in the nCRT group. There was no significant difference in the incidence of grade 3/4 acute toxicity or perioperative complications between the two groups. The 5-year OS [hazard ratio (HR) = 0.84, 95%CI: 0.69-1.02, P = 0.08] and DFS (HR = 0.94, 95%CI: 0.03-1.39, P = 0.74) of the TNT group were similar to those of the nCRT group.

CONCLUSION

TNT has greater clinical efficacy and safety than nCRT in the treatment of locally advanced rectal cancer.

Digitally assessed lymphocyte infiltration in rectal cancer biopsies is associated with pathological response to neoadjuvant therapy

A frequently used treatment strategy in locally advanced rectal cancer (RC) is neoadjuvant therapy followed by surgery. Patients treated with neoadjuvant therapy achieve varying pathological response, and currently, predicting the degree of response is challenging. This study examined the association between digitally assessed histopathological features in the diagnostic biopsies and pathological response to neoadjuvant therapy, aiming to find potential predictive biomarkers. 50 patients with RC treated with neoadjuvant chemotherapy and/or radiotherapy followed by surgery were included. Deep learning-based digital algorithms were used to assess the epithelium tumor area percentage (ETP) based on H&E-stained slides, and to quantify the density of CD3+ and CD8+ lymphocytes, as well as the CD8+/CD3+ lymphocyte percentage, based on immunohistochemically stained slides, from the diagnostic tumor biopsies. Pathological response was assessed according to the Mandard method. A good pathological response was defined as tumor regression grade (TRG) 1-2, and a complete pathological response was defined as Mandard TRG 1. Associations between the ETP and lymphocyte densities in the diagnostic biopsies and the pathological response were examined. The density of CD8+ lymphocytes, and the CD8+/CD3+ lymphocyte percentage, were associated with both good and complete response to neoadjuvant therapy, while the density of CD3+ lymphocytes was associated with complete response. The ETP did not correlate with response to neoadjuvant therapy. It is well-known that infiltration of lymphocytes in colorectal cancer is a prognostic biomarker. However, assessment of CD8+ and CD3+ lymphocytes in the diagnostic tumor biopsies of patients with RC may also be useful in predicting response to neoadjuvant therapy.