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.
Study Type
OBSERVATIONAL
Enrollment
26
Thymalfasin (thymosin-alpha 1) is an immunomodulating agent able to enhance the Thl immune response. It has been evaluated for its immunomodulatory activities and related therapeutic potential in several diseases.
Beijing Friendship Hospital, Capital medical University
Beijing, Xicheng Dis, China
pathologic complete response
All the enrolled patients will receive total mesorectal excision (TME) 7-9 weeks after the end of long course radiotherapy. The rectal specimens will be evaluated by the pathologists who are experienced on the rectal cancer diagnosis according to the 1997 Dworak grading system. The rectal cancer will be classified into 5 grades. Grade 0-3 will be considered as non-pCR while grade 4 represent pCR.
Time frame: 1 year
neoadjuvant rectal (NAR) score
The neoadjuvant rectal (NAR) score is a promising indicator of survival after preoperative chemoradiotherapy for rectal cancer. The NAR score was calculated according to the following formula: NAR score = \[5pN - 3(cT - pT) + 12\]2⁄9.61. (clinical tumor (cT) stage, pathologic tumor (pT) stage, pathologic nodal (pN) stage)
Time frame: 1 year
tumor regression grade(TRG)
AJCC 8th TRG classification. TRG 0: No viable cancer cells left in the specimen; complete regression. TRG 1: Minimal residual cancer cells present; extensive regression with a minimal number of tumor cells. TRG 2: Moderate residual cancer cells present; substantial regression with a significant number of tumor cells. TRG 3: Minimal or no regression; no significant tumor cell response to treatment; majority of tumor still present.
Time frame: 1 year
objective response rate (ORR)
ORR is evaluated according to Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. The ORR rate is the sum of complete response (CR) and partial response (PR)
Time frame: 1 year
R0 resection rate
During the surgical process, the surgeon will evaluate the level of cancer resection. It will be classified as R0, R1, R2 resection. Therefore, we can calculate R0 resection rate.
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Time frame: 1 year
anal preservation rate
the surgeon will decide whether the anal can be preserved on the basis of the rectal cancer and intraoperative situation. anal preservation rate is the percentage of patients who achieve anal preservation.
Time frame: 1 year
disease free survival (DFS)
During the 3-year follow-up, the percentage of the patients who is disease free.
Time frame: 3 year
local recurrence free survival
During the 3-year follow-up, the percentage of local recurrence.
Time frame: 3 year
overall survival (OS)
During the 3-year follow-up, the percentage of the patients who is sill survival at the end of follow-up.
Time frame: 3 year