Neoadjuvant Therapy and Surgery in Rectal Adenocarcinoma: Analysis of Patients with Complete Tumor Remission

Short-Term Clinical and Oncological Outcome of Prolonging Operation Interval After Neoadjuvant Chemoradiotherapy for Locally Advanced Middle and Low Rectal Cancer

Purpose

The purpose of this study is to evaluate the short-term clinical and oncological outcome of prolonging operation interval to 11 weeks after the end of radiotherapy for locally advanced middle and low rectal cancer.

Methods

A total of 123 patients with stage II/III (cT3/T4 or N+) low and middle rectal cancer who had undergone operation after neoadjuvant chemoradiotherapy were selected. According to the interval time between the last radiotherapy and operation, they were assigned to a short-interval group (SG, <11 weeks, n=66) and long-interval group (LG, ≥11 weeks, n=57). The relations among interval time and short-term clinical outcome and oncological outcome were analyzed.

Results

The analysis found that basic information, clinical characteristics, and preoperative treatment between the two groups had no significant difference. There were no differences in operation time, estimated intraoperative blood loss and postoperative complications. The rate of sphincter preservation in the low and middle rectum was 66.7% in the short-interval group and 59.7% in the long-interval group (P=0.42). The incidence of anastomotic leak in the long-interval group was higher than that in the short-interval group (P=0.08). There was no significant difference in the recovery time of intestinal function and median duration of hospitalization between the two groups. The pathological complete remission rate was 17.07%. Multivariate analysis showed interval time had no influence on pathological complete remission. There was no significant difference in 3-year overall survival and 3-year disease-free survival between the two groups. The risk of recurrence and metastasis in patients with positive lymph nodes was higher than those with negative lymph nodes (P<0.05), HR=4.812 (95% CI 2.4–9.648).

Conclusion

Prolonging the interval time of operation to 11 weeks after neoadjuvant chemoradiotherapy for middle and low rectal cancer does not improve the pathologic complete remission, morbidity, and mortality. There was no significant effect on oncologic outcome after prolonging the operation interval. Therefore, it is safe to prolong the interval of operation to 11 weeks.

NEOADJUVANT THERAPY AND SURGERY FOR RECTAL CANCER. Comparative study between partial and complete pathological response

BACKGROUND

The approach of locally advanced extra-peritoneal rectal adenocarcinoma implies a treatment with neoadjuvant chemoradiotherapy associated with total mesorectal excision surgery. However, the tumors respond variably to this neoadjuvant therapy, and the mechanisms for response are not completely understood.

OBJECTIVE

Evaluate the variables related to the complete tumor response and the outcomes of patients who underwent surgery, comparing those with partial tumor regression and those with total remission of rectal lesion, at the pathological examination.

METHODS

Retrospective analysis of medical records of 212 patients operated between 2000 and 2010, in which 182 (85.9%) obtained partial remission at neoadjuvant therapy (Group 1) and 30 (14.1%), total remission (Group 2).

RESULTS

No difference was found between the groups in relation to gender, ethnicity, age, tumor distance from the anal verge, occurrence of metastases and synchronous lesions on preoperative staging, dose of radiotherapy and performed surgery. In Group 2, was verified high rate of complete remission when the time to surgery after neoadjuvant therapy was equal or less than 8 weeks (P=0.027), and a tendency of lower levels of pretreatment carcinoembryonic antigen (P=0.067). In pathological analysis, the Group 1 presented in relation to Group 2, more affected lymph nodes (average 1.9 and 0.5 respectively; P=0.003), more angiolymphatic (19.2% and 3.3%; P=0.032) and perineural involvement (15.4% and 0%; P=0.017) and greater number of lymph nodes examined (16.3 and 13.6; P=0.023). In the late follow-up, Group 1 also had lower overall survival than Group 2 (94.1 months and 136.4 months respectively; P=0.02) and disease-free survival (85.5 months and 134.6 months; P=0.004). There was no statistical difference between Group 2 and Group 1 in local recurrence (15% and 3.4%, respectively) and distant metastasis (28% and 13.8%, respectively).

CONCLUSION

In this study, the only factor associated with complete remission of rectal adenocarcinoma was the time between neoadjuvant therapy and surgery. This group of patients had less affected lymph nodes, less angiolymphatic and perineural involvement, a longer overall and disease-free survival, but no significant statistical difference was observed in local recurrence and distant metastasis. Although the complete pathologic remission was associated with better prognosis, this not implied in the cure of the disease for all patients.