Impact of the distal resection margin on local recurrence after neoadjuvant chemoradiation and rectal excision for locally advanced rectal cancer

Comparison of apparent diffusion coefficients of resectable mid‑high rectal adenocarcinoma and distal paracancerous tissue

Paracancerous tissues actively communicate with the tumor and undergo molecular alterations associated with tumorigenesis. Apparent diffusion coefficient (ADC) can help distinguish between rectal adenocarcinoma (RA), tumor-adjacent and tumor-distant tissues. Preoperative determining optimal distal resection margin (DRM) is crucial for formulating surgical options. The present study aimed to assess ADC differences between RA and 1 cm-layer distal paracancerous tissues, providing a potential reference basis for preoperatively determining optimal DRM. A total of 110 consecutive patients with mid-high RA undergoing preoperative diffusion-weighted imaging were included. ADCs of RA and distal paracancerous tissues located ~1, 2 and 3 cm from the tumor margin (defined as D1, D2 and D3, respectively) were measured using five b-value pairs (0 and 50; 0 and 100; 0 and 800; 0 and 1,000; and 0 and 1,500 sec/mm2). Differences in ADCs between RA, D1, D2 and D3 were compared using the Friedman test with a post hoc Bonferroni correction. Variables that demonstrated statistical differences in multiple pairwise comparisons underwent receiver operating characteristic (ROC) analysis to assess diagnostic performance of ADCs in distinguishing between tissues. ADC at all b-value pairs demonstrated satisfactory performance in distinguishing RA from D1, D2 and D3 [areas under the ROC curves (AUCs), 0.838 to 0.996)]. When the maximum b-value was ≥800 sec/mm2, the ADC of D1 was significantly lower compared with those of D2 and D3 (P<0.001). ADC exhibited an optimal performance in differentiating D1 from D2 at b-values of 0 and 800 sec/mm2, and D1 from D3 at b-values of 0 and 1,000 sec/mm2 (AUCs: 0.652 and 0.692, respectively). However, ADCs of D2 and D3 demonstrated no differences at all b-value pairs (all P>0.05). In conclusion, ADC may distinguish RA from D1, D2 and D3, and D1 from D2/D3, but cannot distinguish between D2 and D3.

Ultrasound assessment of the distal resection margin during robotic rectal surgery

AIM

Ensuring an adequate distal resection margin (DRM) is a key factor in achieving the gold standard in surgical treatment for rectal surgery. The aim of this article is to describe our surgical technique and the usefulness of intraoperative ultrasonography (IOUS) for evaluating the DRM during robotic rectal surgery (RRS).

METHOD

Prospective data on five consecutive patients with rectal cancer who underwent RRS between January 2023 and December 2023 were collected. IOUS was utilized to evaluate the DRM in all patients.

RESULTS

The mean time for the IOUS examination ranged from 5 to 10 min. There were no intraoperative complications or conversions to open surgery. The median length of hospital stay was 6.4 days (±1.67 days). During hospitalization, one patient experienced a Grade II complication according to the Clavien-Dindo classification, specifically postoperative ileus. Furthermore, one patient experienced a delayed anastomotic fistula, which was conservatively treated without readmission. At definitive pathology, the median distance of the tumour from the DRM was 29 mm (±1.41 mm) and all patients had an R0 resection.

CONCLUSION

IOUS is a reproducible and helpful modality for identifying the distal margin of the cutting line during robotic resection of rectal cancers. It does not affect the operating time compared with other methods and could be an alternative method for assessment of the DRM during RRS.

Comparison of outcomes of abdominoperineal resection vs low anterior resection in very-low rectal cancer

BACKGROUND

The management of very-low rectal cancer is one of the most challenging issues faced by general and colorectal surgeons. Many feel compelled to pursue abdominoperineal resection (APR) over low anterior resection (LAR) to optimize oncologic outcomes. This study aimed to determine differences in long-term oncologic outcomes between patients undergoing APR or LAR for very-low rectal cancer.

METHODS

The United States Rectal Cancer Consortium (2010-2016) was queried for adults who underwent either APR or LAR for stage I-III rectal cancers < 5 cm from anorectal junction and met inclusion criteria. The primary outcome was disease-free survival. Secondary outcomes included overall survival, length of stay, complications, recurrence location, and perioperative factors.

RESULTS

A total of 431 patients with very-low rectal cancer who underwent APR or LAR were identified; 154 (35.7%) underwent APR. The overall recurrence rate was 19.6%. The median follow-up was 42.5 months. An analysis adjusted for demographics and pathologic stage observed no difference in disease-free survival between operative types (APR-hazard ratio [HR] = 0.90, 95% CI: 0.53-1.52, P = .70). Secondary outcomes demonstrated no significant difference between operation types, including overall survival (HR = 1.29, 95% CI: 0.71-2.32, P = .39), complications (OR = 1.53, 95% CI: 0.94-2.50, P = .12), or length of stay (estimate: 0.04, SE = 0.25, P = .54).

CONCLUSION

We observed no significant difference in disease-free survival or overall survival between patients undergoing APR or LAR for very-low rectal cancer. This analysis supports the treatment of very-low rectal cancer, without sphincter involvement, by either APR or LAR.

[Postoperative Imaging Findings of Colorectal Surgery: A Pictorial Essay]

Postoperative colorectal imaging studies play an important role in the detection of surgical complications and disease recurrence. In this pictorial essay, we briefly describe methods of surgery, imaging findings of their early and late complications, and postsurgical recurrence of cancer and inflammatory bowel disease.

Determining the optimal distal resection margin in rectal cancer patients by imaging of large pathological sections: An experimental study

OBJECTIVE

To determine the distal resection margin in sphincter-sparing surgery in patients with low rectal cancer based on imaging of large pathological sections.

METHODS

Patients who underwent sphincter-sparing surgery for ultralow rectal cancer at Guangxi Medical University Cancer Hospital within the period from January 2016 to March 2022 were tracked and observed. The clinical and pathological data of the patients were collected and analyzed. The EVOS fluorescence automatic cell imaging system was used for imaging large pathological sections. Follow-up patient data were acquired mainly by sending the patients letters and contacting them via phone calls, and during outpatient visits.

RESULTS

A total of 46 patients (25 males, 21 females) aged 27 to 86 years participated in the present study. Regarding clinical staging, there were 9, 10, 16, and 10 cases with stages I, II, III, and IV low rectal cancer, respectively. The surgical time was 273.82 ± 111.51 minutes, the blood loss was 123.78 ± 150.91 mL, the postoperative exhaust time was 3.67 ± 1.85 days, and the postoperative discharge time was 10.36 ± 5.41 days. There were 8 patients with complications, including 3 cases of pulmonary infection, 2 cases of intestinal obstruction, one case of pleural effusion, and one case of stoma necrosis. The longest and shortest distal resection margins (distances between the cutting edges and the tumor edges) were 3 cm and 1 cm, respectively. The minimum length of the extension areas of the tumor lesions in the 46 images of large pathological sections was 0.1 mm, and the maximum length was 15 mm. Among the tumor lesions, 91.30% (42/46) had an extension area length of ≤5 mm, and 97.83% (45/46) had an extension area length of ≤10 mm. The length of the extension zone was not related to clinical pathological parameters (P > .05).

CONCLUSION

In the vast majority of cases, the distal resection margin was at least 1 cm; thus, "No Evidence of Disease" could have been achieved. Additional high-powered randomized trials are needed to confirm the results of the present study.

Intensification of Local Therapy With High Dose Rate, Intraoperative Radiation Therapy (HDR-IORT) and Extended Resection for Locally Advanced and Recurrent Colorectal Cancer

BACKGROUND

We report our long-term experience with high dose rate intraoperative radiotherapy (HDR-IORT) in a single, quaternary institution.

PATIENTS/METHODS

From 2004 to 2020, 60 HDR-IORT procedures for locally advanced colorectal cancer (LACC) and 81 for locally recurrent colorectal cancer (LRCC) were done in our institution. Preoperative radiotherapy was done prior to majority of the resections (89%, 125/141). Sixty-nine percent (58/84) of the resections involving pelvic exenterations had >3 en bloc organs resected. HDR-IORT was delivered using a Freiburg applicator. A single 10 Gy fraction was delivered. Margin status was R0 and R1 in 54% (76/141) and 46% (65/141) of the resections, respectively.

RESULTS

With a median follow-up time of 4 years, 3-, 5-, and 7- year, overall survival (OS) rates were 84%, 58%, and 58% for LACC and 68%, 41%, and 37% for LRCC, respectively. Local progression-free survival (LPFS) rates were 97%, 93%, and 93% for LACC and 80%, 80%, 80% for LRCC, respectively. For the LRCC group, an R1 resection was associated with worse OS, LPFS, and progression-free survival (PFS), preoperative EBRT was associated with improved LPFS and PFS, and ≥2 years disease-free interval was associated with improved PFS. The most common severe adverse events were postoperative abscess (n = 25) and bowel obstruction (n = 11). There were 68 grade 3 to 4 and no grade 5 adverse events.

CONCLUSIONS

Favorable OS and LPFS can be achieved for LACC and LRCC with intensive local therapy. In patients with risk factors for poorer outcomes, optimization of EBRT and IORT, surgical resection, and systemic therapy are required.

Advantages of ligating the rectum with gauze pad band in laparoscopic anterior resection of rectal cancer: a propensity score matched analysis

Purpose

It is difficult to maintain sufficient tension throughout laparoscopic anterior resection with total mesorectal excision, which causes a decline in surgical quality. We used a soft, inexpensive gauze pad band pulling the rectal tube to analyze the effect of surgery.

Methods

A gauze pad band was positioned at the proximal of the tumor, followed by fastening the rectal tube and ligating the rectum. 233 patients undergoing laparoscopic anterior resection for mid to low rectal cancer were enrolled between January 2018 and December 2020. After propensity score matching, 63 cases were selected in gauze pad band group and 126 cases were selected in traditional group. The two groups were compared in preoperative, intraoperative, and pathological characteristics.

Results

Compared to traditional group, the median operation duration (203 min vs. 233 min, p < 0.001) and the median intraoperative bleeding (48 ml vs. 67 ml, p < 0.001) were lesser in gauze pad band group. A higher percentage of one cartridge transection of rectum (36/63 vs. 51/126, p = 0.030), shorter length of cartridges used (6.88 ± 1.27 cm vs. 7.28 ± 1.25 cm, p = 0.040), and longer distal resection margin (2.74 ± 0.76 cm vs. 2.16 + 0.68 cm, p < 0.001) were found in the gauze pad band group. The completeness of total mesorectal excision (61/63 vs. 109/126, p = 0.022), harvested lymph nodes (19 vs. 17, p < 0.001) and positive lymph nodes (1 vs. 0, p = 0.046) were higher in gauze pad band group.

Conclusion

Ligation of the rectum with a gauze pad band allows for a reduction in operative time and intraoperative bleeding while increasing the rate of one cartridge transection. It also protected the quality of total mesorectal excision and membrane anatomy.

Trial registration: Not applicable.

Association of levels of metabolites with the safe margin of rectal cancer surgery: a metabolomics study

Background

Rectal cancer is one of the most lethal of gastrointestinal malignancies. Metabonomics has gradually developed as a convenient, inexpensive and non-destructive technique for the study of cancers.

Methods

A total of 150 tissue samples from 25 rectal cancer patients were analyzed by liquid chromatography–mass spectrometry (LC–MS), and 6 tissue samples were collected from each patient (group 1: tumor; group 2: 0.5 cm from tumor; group 3:1 cm from tumor; group 4:2 cm from tumor; group 5:3 cm from tumor and group 6:5 cm from tumor). The differential metabolites of tumor tissues and 5 cm from the tumor (normal tissues) were first selected. The differential metabolites between tumor tissues and normal tissues were regrouped by hierarchical clustering analysis, and further selected by discriminant analysis according to the regrouping of clustering results. The potential safe margin of clinical T(cT)1,cT2 stage rectal cancer and cT3,cT4 stage rectal cancer at the metabolomic level was further identified by observing the changes in the level of differential metabolites within the samples from group 1 to group 6.

Results

We found 22 specific metabolites to distinguish tumor tissue and normal tissue. The most significant changes in metabolite levels were observed at 0.5 cm (cT1, cT2) and 2.0 cm (cT3, cT4) from the tumor, while the changes in the tissues afterwards showed a stable trend.

Conclusions

There are differential metabolites between tumor tissues and normal tissues in rectal cancer. Based on our limited sample size, the safe distal incision margin for rectal cancer surgery in metabolites may be 0.5 cm in patients with cT1 and cT2 stage rectal cancer and 2.0 cm in patients with cT3 and cT4 stage rectal cancer.

Is a Distal Resection Margin of ≤ 1 cm Safe in Patients with Intermediate- to Low-Lying Rectal Cancer? A Systematic Review and Meta-Analysis

BACKGROUND

It is generally accepted that the distal resection margin of intermediate- to low-lying rectal cancer should be greater than 2 cm and at least 1 cm in special cases. This study intends to investigate whether a distal resection margin ≤ 1 cm affects tumor outcomes for patients with intermediate- to low-lying rectal cancer.

METHODS

A systematic review of the literature was conducted. Sixteen studies included data for distal resection margins ≤ 1 cm (1684 cases) and > 1 cm (5877 cases), and 5 studies included survival data. Meta-analysis was used to compare the local recurrence rate and long-term survival of patients with distal resection margins > or ≤ 1 cm.

RESULTS

The local recurrence rate in the ≤ 1-cm margin group (9.5%) was 2.3% higher than that in the > 1-cm margin group (7.2%) according to a fixed-effects model (RR [95% CI] 1.42 [1.18, 1.70], P < 0.001). The overall survival results of the five 1-cm margin studies showed an HR (95% CI) of 0.96 (0.75, 1.24) (P = 0.78). Subgroup analysis showed that the local recurrence rate in the subgroup with perioperative treatment was 1.2% lower in the ≤ 1-cm margin group (8.3%) than in the > 1-cm margin group (9.5%) (RR [95% CI] 0.97 [0.63, 1.49], P = 0.90). In the surgery alone subgroup, the local recurrence rate was 4.7% higher in the ≤ 1-cm margin group (12.4%) than in the > 1-cm group (7.7%) (RR [95% CI] 1.76 [1.09, 2.83], P = 0.02).

CONCLUSIONS

For patients with intermediate- to low-lying rectal cancer undergoing surgery alone, a distal resection margin ≤ 1 cm may be not safe.