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[Efficacy analysis of neoadjuvant chemoradiotherapy combined with total pelvic exenteration in the treatment of primary T4b rectal cancer].

OBJECTIVE
To investigate the value of neoadjuvant chemoradiotherapy (nCRT) combined with total pelvic exenteration (TPE) in the treatment of primary T4b rectal cancer.


METHODS
A retrospective cohort study was conducted to analyze the clinicopathological data of 31 patients with primary T4b rectal cancer who underwent TPE from January 2008 to December 2015 at Peking University First Hospital.


INCLUSION CRITERIA
preoperative clinical stage (cTNM) was defined as cT4b primary rectal cancer with only front wall Invasion; the lower edge of tumor was within 10 cm from the anal margin; TPE was performed; R0 resection was confirmed by pathology. Patients with recurrent rectal cancer, distant metastasis, and undergoing TPE for non-rectal tumors were excluded. Patients were divided into nCRT group and non-nCRT group according to whether receiving nCRT before surgery. The nCRT group received long course radiotherapy (total dose 50 Gy in 25 daily fractions) with concomitant chemotherapy (Capecitabine), and the surgery was performed 6-8 weeks after the neoadjuvant chemoradiation, while the non-nCRT group received surgery directly. The intraoperative, postoperative and pathological conditions and local recurrence were compared between the two groups. The survival curves were drawn by Kaplan-Meier method and the survival of two groups were compared.


RESULTS
A total of 31 patients were enrolled, including 13 patients in the nCRT group and 18 patients in the non-nCRT group. The baseline data, such as age, duration of disease, preoperative basic disease, body mass index, smoking rate, and tumor distance from the anal margin, were not significantly different between the two groups (all P>0.05). In the nCRT group and non-nCRT group respectively, the ratio of anal preservation was 30.8%(4/13) and 38.9%(7/18) (P=0.468), the median intraoperative blood loss was 1 000 ml and 800 ml (P=0.644), the operation time was (531.7±137.2) minutes and (498.0±90.1) minutes (P=0.703), the median hospital stay was 18 days and 14 days (P=0.400), the morbidity of complications within 30 days after surgery was 23.1%(3/13) and 38.9%(7/18)(P=0.452), the incidence of postoperative abdominal abscess was 15.4%(2/13) and 0 (P=0.168), the proportion of secondary surgery was 7.7%(1/13) and 11.1%(2/18)(P=1.000), whose differences were not significantly different. The proportion of postoperative pathological pT4b in whole group was 58.1%(18/31), including 53.8%(7/13) in nCRT group and 61.1%(11/18) in non-nCRT group, which was not significantly different between the two groups (P=0.691). The number of harvested lymph node in nCRT group was 13.5±5.9, which was significantly less than 23.0±11.8 in non-nCRT group (P=0.013). There was no pathological complete remission (ypCR) case in nCRT group, and among 13 patients, tumor regression grade (TRG) of 2, 3, 4, and 5 was in 1 case (7.7%), 6 cases (46.2%), 5 cases(38.5%), and 1 case (7.7%), respectively. The median follow-up time was 33 (2 to 115) months, and the follow-up rate was 93.5%(29/31). One case was lost in both the nCRT group and non-nCRT group. The 3-year disease-free survival rate was 43.5% in pooled data, and was 43.6% and 43.3% in nCRT group and non-CRT group respectively without significant difference (P=0.833). The 3-year overall survival rate was 51.1% in pooled data, and was 45.7% and 54.7% in nCRT group and non-nCRT group respectively without significant difference (P=0.653).The local recurrence rate of nCRT and non-nCRT groups was 8.3%(1/12) and 5.9%(1/17) respectively, and the distant metastasis rate was 50.0%(6/12) and 41.2%(7/17) respectively, whose differences were not statistically significant as well (P=1.000 and P=0.865, respectively).


CONCLUSION
For primary T4b rectal cancer which can achieve R0 resection through total pelvic exenteration, neoadjuvant chemoradiotherapy has not been demonstrated any advantage in tumor regression, reducing local recurrence, or improving survival, and may increase postoperative complications.