The Role of the Laparoscopy on Circumferential Resection Margin Positivity in Patients With Rectal Cancer: Long-term Outcomes at a Single High-volume Institution

Progress of MRI in predicting the circumferential resection margin of rectal cancer: A narrative review

Rectal cancer (RC) is the third most frequently diagnosed cancer worldwide, and the status of its circumferential resection margin (CRM) is of paramount significance for treatment strategies and prognosis. CRM involvement is defined as tumor touching or within 1 mm from the outermost part of tumor or outer border of the mesorectal or lymph node deposits to the resection margin. The incidence of involved CRM varied from 5.4 % to 36 %, which may associate with an in consistent definition of CRM, the quality of surgeries, and the different examination modalities. Although T and N status are essential factors in determining whether a patient should receive neoadjuvant therapy before surgery, CRM status is a powerful predictor of local and distant recurrence as well as survival rate. This review explores the significance of CRM, the various assessment methods, and the role of magnetic resonance imaging (MRI) and artificial intelligence-based MRI in predicting CRM status. MRI showed potential advantage in predicting CRM status with a high sensitivity and specificity compared to computed tomography (CT). We also discuss MRI advancements in RC imaging, including conventional MRI with body coil, high-resolution MRI with phased-array coil, and endorectal MRI. Along with a discussion of artificial intelligence-based MRI techniques to predict the CRM status of RCs before and after treatments.

Prognostic importance of circumferential resection margin in the era of evolving surgical and multidisciplinary treatment of rectal cancer: A systematic review and meta-analysis

BACKGROUND

Circumferential resection margin is considered an important prognostic parameter after rectal cancer surgery, but its impact might have changed because of improved surgical quality and tailored multimodality treatment. The aim of this systematic review was to determine the prognostic importance of circumferential resection margin involvement based on the most recent literature.

METHODS

A systematic literature search of MEDLINE, Embase, and the Cochrane Library was performed for studies published between January 2006 and May 2019. Studies were included if 3- or 5-year oncological outcomes were reported depending on circumferential resection margin status. Outcome parameters were local recurrence, overall survival, disease-free survival, and distant metastasis rate. The Newcastle Ottawa Scale and Jadad score were used for quality assessment of the studies. Meta-analysis was performed using a random effects model and reported as a pooled odds ratio or hazard ratio with 95% confidence interval.

RESULTS

Seventy-five studies were included, comprising a total of 85,048 rectal cancer patients. Significant associations between circumferential resection margin involvement and all long-term outcome parameters were uniformly found, with varying odds ratios and hazard ratios depending on circumferential resection margin definition (<1 mm, ≤1 mm, otherwise), neoadjuvant treatment, study period, and geographical origin of the studies.

CONCLUSION

Circumferential resection margin involvement has remained an independent, poor prognostic factor for local recurrence and survival in most recent literature, indicating that circumferential resection margin status can still be used as a short-term surrogate endpoint.

Comparison of laparoscopic vs. open surgery for rectal cancer

This study was conducted to evaluate the safety of laparoscopic radical resection for rectal cancer. A total of 64 cases of rectal cancer patients undergoing radical surgery between January, 1998 and March, 2010 were collected. The patients were divided into the laparoscopic rectal surgery group (LS group, n=31) and the open surgery group (OS group, n=33). Operation time, postoperative recovery, complications and tumor-free survival rate were compared between the two groups. The inclusion criteria were as follows: Standard Karnofsky score >70 prior to surgery, definitive pathological diagnosis and complete clinical data. The exclusion criteria were concomitant tumors affecting survival. With the Dixon operation, the LS group had a longer operation time compared with the OS group (271.2±56.2 vs. 216.0±62.7 min, respectively; P=0.036), and an earlier time of oral intake (3.0±0.9 vs. 4.7±1.0 days, respectively; P=0.000). There were no significant differences between the LS and OS groups in terms of intraoperative blood loss, number of lymph nodes retrieved, duration of postoperative hyperthermia and hospitalization time (P>0.05). With the Miles operation, there were no obvious differences between the LS and OS groups regarding operation time, intraoperative blood loss, number of lymph nodes retrieved, time of oral intake, duration of postoperative hyperthermia and hospitalization time (P>0.05). Furthermore, there were no significant differences between the LS and OS groups with the Dixon or Miles operation in terms of 3-year tumor-free survival rate (P>0.05). Thus, laparoscopic surgery appears to be a safe and feasible option for the treatment of rectal cancer.

Sparing Sphincters and Laparoscopic Resection Improve Survival by Optimizing the Circumferential Resection Margin in Rectal Cancer Patients

The goal of rectal cancer treatment is to minimize the local recurrence rate and extend the disease-free survival period and survival. For this aim, obtainment of negative circumferential radial margin (CRM) plays an important role. This study evaluated predictive factors for positive CRM status and its effect on patient survival in mid- and distal rectal tumors.Patients who underwent curative resection for rectal cancer were included. The main factors were demographic data, tumor location, surgical technique, neoadjuvant therapy, tumor diameter, tumor depth, lymph node metastasis, mesorectal integrity, CRM, the rate of local recurrence, distant metastasis, and overall and disease-free survival. Statistical analyses were performed by using the Chi-squared test, Fisher exact test, Student t test, Mann-Whitney U test and the Mantel-Cox log-rank sum test.A total of 420 patients were included, 232 (55%) of whom were male. We observed no significant differences in patient characteristics or surgical treatment between the patients who had positive CRM and who had negative CRM, but a higher positive CRM rate was observed in patients undergone abdominoperineal resection (APR) (P < 0.001). Advanced T-stage (P < 0.001), lymph node invasion (P = 0.001) and incomplete mesorectum (P = 0.007) were encountered significantly more often in patients with positive CRM status. Logistic regression analysis revealed that APR (P < 0.001) and open resection (P = 0.046) were independent predictors of positive CRM status. Moreover, positive CRM was associated with decreased 5-year overall and disease-free survival (P = 0.002 and P = 0.004, respectively).This large single-institution series demonstrated that APR and open resection were independent predictive factors for positive CRM status in rectal cancer. Positive CRM independently decreased the 5-year overall and disease-free survival rates.