Impact of rectal washout on recurrence and survival after anterior resection for rectal cancer

Can neoadjuvant chemoradiotherapy affect exfoliated cancer cells in colorectal cancer?

BACKGROUND

To prevent local recurrence caused by exfoliated cancer cells caught in the suture line, intraoperative rectal washout during surgery can be performed to eliminate exfoliated cancer cells. However, the impact of neoadjuvant chemoradiotherapy on exfoliated cancer cells is not well known. This study aimed to identify positive rate of malignant cells in rectal washout fluids of neoadjuvant chemoradiotherapy patients and to determine if neoadjuvant chemoradiotherapy could affect exfoliated cancer cells.

METHODS

A total of 105 patients who underwent rectal washout intraoperatively for distal sigmoid colon and rectal cancer from April 2020 to September 2021 were analyzed. The primary outcome was positive rate of malignant cells in rectal washout fluids of patients who had received neoadjuvant chemoradiotherapy.

RESULTS

The positive rate of malignant cells in washout fluids of patients who had received neoadjuvant chemoradiotherapy was 0.0% and those who had not was 32.1%. The overall positive rate was 23.8%. In the positive group, tumor sizes were bigger (4.64 ± 1.68 cm vs. 3.64 ± 2.00 cm, p = 0.026) and more patients had a fungating tumor shown in preoperative colonoscopy (96.0% vs. 71.3%, p = 0.012). Although these factors did not show statistical significance in multivariable logistic regression analysis, fungating tumor showed a trend towards significance (OR: 7.28, 95% CI: 0.90-58.77, p = 0.063).

CONCLUSIONS

Our study suggests that neoadjuvant chemoradiotherapy could reduce exfoliated cancer cells, and rectal washout for the purpose of eliminating exfoliated cancer cells might be unnecessary in patients who have received neoadjuvant chemoradiotherapy.

Development of novel rectal/uterine clamping device

We developed a novel clamping device for laparoscopic surgery, free from conventional pinch structure, capable of uniformly occluding any ductal organ. This study aimed to evaluate performance of the new clamper compared to the pinch-type clamper. The new clamper consists of two metal bars with ties at each end, which enables parallel clamping. A resected porcine stomach was used, with an infusion tube at the anal end to increase intra-luminal pressure. The oral side of the stomach was clamped with either the new clamper or the pinch-type clamper, and their performances were evaluated in qualitative and semi-quantitative manner. Qualitative evaluation involved imaging the clamping site at intra-gastric pressures from 0 to 15 mmHg using microfocus computed tomography. The new clamper showed no gap even under increased intra-luminal pressure, while the pinch-type clamper showed a gap on the distal side. Quantitative evaluation measured bursting pressure under continuous air insufflation. Air leakages were observed in the new clamper at higher intra-luminal pressures than in the pinch-type clamper (46.1 mmHg vs. 13.6 mmHg, P < 0.01). Our new clamping device showed superior performance in preclinical setting compared to the conventional pinch-type clamper. We are currently working on its design freezing and aiming for early commercialization.

Impact of rectal washout in local recurrence: a meta-analysis and systemic review

Introduction

Rectal washout is proposed for eliminating free cancer cells, yet evidence on its efficacy in preventing local recurrence after anterior resection is inconclusive.

Material and methods

Contrasting rectal washout (RW) and non-rectal washout (NRW) in rectal cancer, a prospective study of randomized control trials (RCT) and non-randomized control trials (NRCT) from January 2005 to July 2023 was conducted using PubMed, Cochrane Library, and MEDLINE databases. Meta-statistical analysis in RevMan 5.4 addressed heterogeneity.

Results

In analysis involving 19,855 patients (15127 RW, 4728 NRW) from eight studies, RW significantly reduced local recurrence (OR = 0.48), intraoperative RW (OR = 0.65), radical resection margins (OR = 1.89), and neoadjuvant therapy (OR = 0.99) (all p < 0.05). Subgroup RCT analysis reinforced these findings.

Conclusions

Rectal washout correlates with improved outcomes, while non-washout patients benefit more from neoadjuvant therapy. Notably, rectal washout without neoadjuvant remains efficacious.

Intraoperative esophageal washout reduces free intraluminal tumor cells during resection of carcinomas of the esophagus and cardia

OBJECTIVE

Intraluminally shed viable tumor cells might contribute to anastomotic recurrence in cancer of the esophagus and the cardia. The study aimed to establish a method of esophageal washout and, hence, to reduce intraluminal cancer cells before esophageal anastomosis.

METHODS

Forty-eight consecutive patients with esophago-gastric resection for histologically proven cancer of the esophagus or the cardia were included in a prospective, interventional study. Before transection, the esophagus was clamped proximally to the tumor and rinsed with 1:10 diluted povidone-iodine-solution (10 × 30 ml) applied by a transorally inserted 24F-Foley catheter. The first, fifth and tenth portion of the lavage fluid were sent to cytological examination.

RESULTS

Intraoperative frozen sections confirmed clear proximal resection margins of the esophagus. The cytological examination of the fluid recovered from the esophageal washout revealed malignant cells in 13/48 patients (27%). The presence of malignant cells was significantly less likely in patients with neoadjuvant treatment than in patients without neoadjuvant treatment: 2/23 (9%) vs. 11/25 (44%) (p = 0.009). Repetitive washout reduced the probability of detectable malignant cells from 13 to 8 (62%) patients after 5, and further to 4 patients (30%) after 10 washout maneuvers.

CONCLUSIONS

Free malignant cells may be present in the esophageal lumen following intraoperative manipulation of cancers of the esophagus or cardia. Transoral washout of the esophagus is novel, feasible and enables reduction or even elimination of these tumor cells. The reliability of this procedure raises with increasing washout volume. Esophageal washout might be especially worthwhile in patients who do not receive neoadjuvant therapy.