neoadjuvant chemoradiotherapy combined with pd-1 inhibitor and thymalfasin for locally advanced mid-low rectal cancer

Conditions: Colorectal Neoplasms

Summary: it is a single-center, retrospective, controlled study to investigate the efficacy and safety of neoadjuvant chemoradiotherapy combined with pd-1 inhibitor and thymalfasin for locally advanced mid-low rectal cancer.

study purpose 1. to evaluate the efficacy and safety of neoadjuvant chemoradiotherapy combined with pd-1 inhibitor and thymalfasin for locally advanced mid-low rectal cancer. 2. to explore the effects of neoadjuvant chemoradiotherapy combined with pd-1 inhibitor and thymalfasin on the immune microenvironment of locally advanced mid-low rectal cancer. study design: a single-center, retrospective, controlled study subjects were divided into two groups according to whether or not they received thymalfasin: group 1 was treated with neoadjuvant chemoradiotherapy combined with pd-1 inhibitor, and group 2 was treated with neoadjuvant chemoradiotherapy combined with pd-1 inhibitor and thymalfasin. subjects received long course radiotherapy (50 gy/25f, 2 gy/f, 5 days/week) for the first 5 weeks and three 21-day cycles capecitabine (1000 mg/m2, bid, po, day1-14) plus three 21-day cycles tislelizumab (200 mg, iv.gtt, day 8) for the first 9 weeks. after that, patients rested for two weeks (week 10-11)。6-8 weeks after the end of radiotherapy, patients underwent tme surgery (12-14 weeks). thymalfasin was started on the first day of neoadjuvant chemoradiotherapy, 1.6 mg subcutaneously twice a week until the end of the last neoadjuvant treatment. enrollment: 26 participants, 13 in each group study population: locally advanced mid-low rectal cancer primary endpoint: pathologic complete response（pcr） exploratory endpoint: paraffin specimens were collected from biopsies before neoadjuvant therapy and after surgery in patients meeting the inclusion criteria. the expression of cd86, cd163, cd4+t，cd8+t，pd-1 were detected.

Eligibility criteria:
inclusion criteria: * patients with rectal adenocarcinoma must satisfied all the following conditions: 1. stage ii/iii larc (ct1-4an0-2m0); 2. tumor distal location≤10 cm from anal verge (mri diagnosed); * patients regardless of gender with aged≥18 years * ecog score of 0 or 1 * physical and viscera function of patients can withstand major abdominal surgery exclusion criteria: * current or previous active malignancy other than rectal cancer； * patients underwent major surgery within 4 weeks prior to neoadjuvant therapy； * patients have any condition affects the absorption of capecitabine through gastrointestinal tract； * patients have severe uncontrolled recurrent infections, or other severe uncontrolled concomitant diseases; * patients with severe concomitant diseases with estimated survival≤5 years； * patients with present or previous moderate or severe liver and kidney damage； * patients preparing for or previously received organ or bone marrow transplant； * patients who have received immunosuppressive or systemic hormone therapy within 1 month prior to the start of neoadjuvant therapy； * patients with congenital or acquired immune deficiency (such as hiv infection)； * pregnant or lactating women.

Keywords: colorectal neoplasms programmed cell death 1 receptor thymalfasin neoadjuvant therapy