Objective To analyze the effect of preoperative short course radiotherapy and chemotherapy or conventional radiotherapy and chemotherapy on patients with stage ⅢB rectal cancer and determine the differences in the expression of Runt-related transcription factor 3 (Runx3) and cell proliferating nuclear antigen Ki-67 (short for Ki-67) in the resected tissue specimens.

Methods From January 2019 to December 2019, a prospective study was conducted on 100 patients with stage ⅢB rectal cancer in the First Affiliated Hospital of Hebei North University, including 52 males and 48 females, aged 38–79(58.56±9.11) years. All patients were randomly divided into the control group and observation group, with 50 cases in each group. The control group received conventional radiotherapy + chemotherapy before operation, whereas the observation group received short-term radiotherapy + chemotherapy before operation. The operation-related conditions, postoperative pathological T staging reduction rate, pathological complete remission (pCR) rate, occurrence of adverse reactions, local recurrence rate, distant metastasis rate and survival rate were compared between the two groups. Immunohistochemical methods were used to detect the expression score of Runx3 and Ki-67 on the resected rectal cancer tissue samples. The measurement data of the two groups were compared using independent sample t test. When the number of cases was <40 or the theoretical frequency T≤1, Fisher's exact probability method was used. When the number of cases was ≥40 and when the theoretical frequency was T≥5 (uncorrection) or 1<T<5 (correction), the χ² test was used.

Results The operation time ((165.89±18.73) min), intraoperative blood loss ((215.63±56.89) mL), postoperative exhaust time ((62.28±16.47) h), hospitalization time ((13.97±7.11) d), anastomotic leakage rate (6%, 3/50), intestinal obstruction rate (4%, 2/50) and infection rate (4%, 2/50) in the observation group were compared with those in the control group (i.e., (158.14±23.57) min, (227.84±60.75) mL, (59.28±12.04) h, (15.01±5.29) d, 2% (1/50), 0 (0/50) and 8% (4/50), respectively), and the differences were not statistically significant (t=0.854–1.820, χ²=0.260, 0.177, Fisher's exact probability method, all P>0.05). There was no significant difference in the T staging rate and pCR rate between the two groups (χ²=0.160, 0.000; both P>0.05). The total incidence of radiation dermatitis in the observation group (12%, 6/50) was significantly lower than that in the control group (30% (15/50)) (χ²=4.883, P<0.05). The expression score of Runx3 in the specimens resected during operation in the observation group was 2.56±0.51, which was significantly higher than 1.87±0.72 in the control group (t=5.530, P<0.01). The expression score of Ki-67 was 2.39±1.03, which was significantly lower than 3.94±0.46 in the control group (t=9.716, P<0.01). The local recurrence rate (2%,1/50) in the observation group was significantly lower than that (17%, 8/48) in the control group (χ²=5.936, P<0.05).

Conclusions Preoperative short course radiotherapy and chemotherapy for stage ⅢB rectal cancer will not increase the difficulty and risk of total mesorectal excision. It can reduce the occurrence of adverse reactions, and decrease the rate of local recurrence. A statistically significant difference was found in the expression of Runx3 and Ki-67 in surgical resection specimens obtained.