Nomogram to predict permanent stoma in rectal cancer patients after sphincter-saving surgery

BACKGROUND Approximately 20 percent of patients with a tumour localized in the low rectum still encounter the possibility of requiring permanent stoma(PS), which can cause drastic changes in lifestyle and physical perceptions.AIM To determine the risk factors for PS and to develop a prediction model to predict the probability of PS in rectal cancer patients after sphincter-saving surgery.METHODS A retrospective cohort of 421 rectal cancer patients who underwent radical surgery at Taipei Medical University Hospital between January 2012 and December 2020 was included in this study. Univariate and multivariate analyses were performed to identify the independent risk factors for PS. A nomogram was developed according to the independent risk factors obtained in the multivariate analysis. The performance of the nomogram was assessed using a receiver operating characteristic curve and a calibration curve.RESULTS The PS rate after sphincter-saving surgery was 15.1%(59/391) in our study after a median follow-up of 47.3 mo(range 7–114 mo). Multivariate logistic regression analysis demonstrated that local recurrence, perirectal abscess, anastomosis site stenosis, perineural invasion, tumor size and operative time were independent risk factors for PS. These identified risk factors were incorporated into the nomogram, and the concordance index of this model was 0.903(95%CI: 0.851-0.955). According to the calibration curves, the nomogram represents a perfect prediction model.CONCLUSION Several risk factors for PS after sphincter-saving surgery were identified. Our nomogram exhibited perfect predictive ability and will improve a physician’s ability to communicate the benefits and risks of various treatment options in shared decision making.

Increased rate change over time of a sphincter-saving procedure for lower rectal cancer

Background Total mesorectal excision （TME） has increased the rate of sphincter-preservation （SP） for more patients with low-lying rectal cancer. Here, we analyze the change of sphincter preserving rates in lower rectal cancer and their related factors. MethOds We reviewed retrospectively the medical records of 316 patients with lower rectal cancers, 1 to 5 cm from the anorectal line, who had surgical resections from August 1994 to November 2005. The 12-year span was divided into 2 periods： period Ⅰ（August 1994-December 1998） and period Ⅱ （January 1999-November 2005）, based on the date （January 1999） when standard total mesorectal excision （TME） was introduced. The patients were divided into two groups based on the operation： abdominoperineal resection （APR） or SP surgery. SP rates, leakage and other clinicopathological characteristics were compared between the two time periods and between the two different groups. Results The SP rate increased significantly over the 12 years, from 44.9% in period Ⅰ to 76.2% in period Ⅱ （P=0.000）. The factors significantly influencing SP included the distance of the tumor from the anorectal line, gender, time period, circumference of intramural spread and histological differentiation （P 〈0.05）. Significant differences were detected between the two time periods in gender, blood transfusion volume and Dukes＇ stage （P 〈0.05）. The leakage rate was 2.7% in period I and 1.3% in period II （P 〉0.05）. Conclusions Over the 12-year period of the study the SP rate in rectal cancers 1-5 cm from the anorectal line has increased significantly while the blood transfusion volume has decreased due to the introduction of TME. However, TME had no effect on operating time and leakage rates.

Pathological study of distal mesorectal cancer spread to determine a proper distal resection margin

AIM: Local recurrence after curative surgical resection for rectal cancer remains a major problem. Several studies have shown that incomplete removal of cancer deposits in the distal mesorectum contributes a great share to this dismal result. Clinicopathologic examination of distal mesorectum in lower rectal cancer was performed in the present study to assess the incidence and extent of distal mesorectal spread and to determine an optimal distal resection margin in sphincter-saving procedure.METHODS: We prospectively examined sepecimens from 45 patients with lower rectal cancer who underwent curative surgery. Large-mount sections were performed to microscopically observe the distal mesorectal spread and to measure the extent of distal spread. Tissue shrinkage ratio was also considered. Patients with involvement in the distal mesorectum were compared with those without involvement with regard to clinicopathologic features.RESULTS: Mesorectal cancer spread was observed in 21patients (46.7%), 8 of them (17.8%) had distal mesorectal spread. Overall, distal intramural and/or mesorectal spreads were observed in 10 patients (22.2%) and the maximum extent of distal spread in situ was 12 mm and 36 mm respectively. Eight patients with distal mesorectal spread showed a significantly higher rate of lymph node metastasis compared with the other 37 patients without distal mesorectal spread (P = 0.043).CONCLUSION: Distal mesorectal spread invariably occurs in advanced rectal cancer and has a significant relationship with lymph node metastasis. Distal resection margin of 1.5 cm for the rectal wall and 4 cm for the distal mesorectum is proper to those patients who are arranged to receive operation with a curative sphincter-saving procedure for lower rectal cancer.

STATUS OF SURGICAL TREATMENT OF RECTAL CANCER IN CHINA

The multimodality treatment methods of rectal cancer in China are presented. Extended radical excisions are used for Dukes’ B and C cases to reduce local recurrence. These include: high ligation with clearance of proximal lymph nodes at origin of inferior mesenteric artery, lateral pelvic lymphadenectomy, posterior or total pelvic exenterations in selected cases; but controversy exists. Radical sphincter-saving resections are advocated to improve the quality of life. Prerequisites of sphincter-saving resection are adequate resection of bowel and mesentery distal to the lesion, depending on the macroscopic type of lesion and degree of differentiation. The decisive factor in the choice of type of operation is the length of rectal stump above levator ani after resection. Bacon’s pull through resection was modified by preservation of levator ani and dentate margin, much better functional results were obtained postoperatively. Transanal full thickness local excision is advocated for small, protuberant, mobile, well differentiated lesions below the peritoneal reflection. Pre- or postoperative adjuvant radiation therapy is sometimes used for Dukes’ B and C cases. Adjuvant 5-Fu chemotherapy is usually used intraoperatively (intraluminal) or postoperatively (intravenous). The superiority of preoperative intrarectal 5-Fu emulsionover the conventional intravenous route has been demonstrated by experimental and clinical studies, which showed much higher and lasting concentration of 5-Fu in the rectal wall tissues and mesenteric lymph nodes, and a much lower concentration of 5-Fu in bone marrow after intrarectal administration. Several surgical groups employed varying techniques of sphincteric reconstruction of perineal colostomy after abdominoperineal excision, utilizing the gracilis or gluteus maximus sling, or intussusception of the colonic stump; with favorable late results in reported cases. However, controversy exists, so strict appropriate case selection is emphasized to avoid unnecessary sacrifice of the normal anus.