Radical surgery for early colorectal cancer--anachronism or oncologic necessity?

Surgical outcomes of robotic transanal minimally invasive surgery for selected rectal neoplasms: A single-hospital experience

BACKGROUND

Rectal neoplasm is one of the most common malignancies worldwide. Screening programs for rectal neoplasm result in early diagnosis and a decrease in disease-related mortality and morbidity. In selected patients, early rectal cancer may be treated with local excision. Owing to poor exposure during conventional transanal excision, transanal minimally invasive surgery (TAMIS) was developed, and TAMIS is feasible for the local excision of selected rectal neoplasms. However, the limited range of motion is a major disadvantage of this operation. Therefore, robotic TAMIS was developed to resolve this issue. This paper describes the surgical outcomes of robotic TAMIS for selected rectal tumors.

METHODS

The eligibility criteria for robotic TAMIS were as follows: benign neoplasms, early malignancy, complete remission after concurrent chemoradiotherapy, lesions located in the middle or lower rectum, and a lesion size of less than 5 cm. To gain access to the anal canal, a transanal access platform was used, and the da Vinci robotic system was mounted for surgery. Patient characteristics and surgical outcomes were recoded.

RESULTS

A total of 23 patients were included, and the median tumor size was 2.5 cm (range: 1.1-4.5 cm) on average. The median tumor location was 5 cm (range: 2-8 cm) from the anal verge. The median length of hospital stay was 3 days (range: 1-10 days). No intraoperative complications were reported, and no patient readmission occurred. The median follow-up period was 9.6 months. No recurrent lesion was found in the follow-up period.

CONCLUSION

Based on the short-term results, robotic TAMIS is a feasible and safe technique for the local excision of selected rectal neoplasms.

Endoscopic resection of colorectal lesions: The narrowing divide between East and West

Colonic polypectomy is an effective way of reducing colon cancer mortality. Multiple techniques now exist for the resection of polyps, and the endoscopist must decide on the appropriate resection approach for individual patients and lesions. This decision should maximize efficacy, safety and cost-effectiveness and provide optimal oncological outcomes while minimizing unnecessary surgical treatment. Advances in endoscopic imaging technology are improving the accuracy of endoscopic diagnosis and allowing more precise risk assessment of colonic lesions. Resection technique can be tailored to the endoscopic findings. Diminutive (≤5 mm) and small polyps (≤9 mm) are best resected primarily by snare techniques. Cold snare polypectomy has proven safety, but efficacy and technique require further study. There is variation in techniques used for polyps 6-20 mm in size and incomplete resection rates for conventional polypectomy may be considerable. Endoscopic mucosal resection (EMR) is well established, safe and effective for lesions without submucosal invasion (SMI); however, recurrence is a key limitation. Endoscopic submucosal dissection (ESD) is well established in the East; however, it is resource intensive and its role in lesions with a low risk of SMI is questionable. ESD in the West remains incompletely defined and is associated with high adverse event rates, but it is becoming increasingly available and successful as experience grows. Emerging full-thickness resection technologies are still in their infancy and remain experimental as a result of the absence of reliable closure devices and techniques. Patient-focused outcomes should guide technique selection.

Transanal endoscopic microsurgery

Transanal endoscopic microsurgery (TEMS) is a well established method of accurate resection of specimens from the rectum under binocular vision. This review examines its role in the treatment of benign conditions of the rectum and the evidence to support its use and compliment existing endoscopic treatments. The evolution of TEMS in early rectal cancer and the concepts and outcomes of how it has been utilised to treat patients so far are presented. The bespoke nature of early rectal cancer treatment is changing the standard algorithms of rectal cancer care. The future of TEMS in the organ preserving treatment of early rectal cancer is discussed and how as clinicians we are able to select the correct patients for neoadjuvant or radical treatments accurately. The role of radiotherapy and outcomes from combination treatment using TEMS are presented with suggestions for areas of future research.

Oncological outcome of T1 rectal cancer undergoing standard resection and local excision

AIM

We studied the outcome and prognostic factors for T1 rectal cancer patients undergoing standard resection or transanal excision.

METHOD

One hundred and twenty-four patients with T1 rectal cancer were included in the study, of whom 66 (53.2%) underwent standard resection and 58 (46.8%) underwent transanal excision. Survival analysis was performed to compare the outcome.

RESULTS

The 5-year local recurrence rate was 11.0% in the transanal excision group versus 1.6% in the standard resection group (P = 0.031) but the 5-year disease-free survival and overall survival rates were not significantly different between the two groups. Multivariate analysis suggested that a high tumour grade and perineural or lymphovascular invasion were independent risk factors for local recurrence and recurrence-free survival. For high-risk patients (with at least one of the above risk factors), the 5-year local recurrence and 10-year recurrence-free survival rates were 21.2% and 74.5%, versus 1.2% and 92.0% in low-risk patients (P = 0.00003 and P = 0.003). In patients undergoing transanal excision, none in the low-risk group had local recurrence during follow up, while 40% (6 of 15) of patients in the high-risk group developed local recurrence within 5 years after surgery. The 5-year local recurrence rate was 45.0%.

CONCLUSION

Transanal excision in T1 rectal cancer may result in a high rate of local failure for patients with a high-grade tumour, or perineural or lymphovascular invasion. Local excision should be avoided as a curative treatment in high-risk patients.

Localized resection for colon cancer

Localized resection of early stage colon cancer is increasingly technically feasible by truly minimally invasive means. Such techniques as endoscopic submucosal dissection (ESD) and Natural Orifice Transluminal Endoscopic Surgery (N.O.T.E.S.) now raise the prospect of focused intraluminal and transmural resection of small primary tumors without abdominal wall transgression. The potential clinical benefit that patients may accrue from targeted dissection as definitive treatment in place of radical operation is not yet definitively proven but may be considerable at least in the short-term. However, oncological propriety and outcomes must be maintained. In particular methods by which regional nodal staging can be assured if standard operation is avoided need still to be established. Sentinel node mapping is one such putative means of doing so that deserves serious consideration from this perspective as it performs a similar function for breast cancer and melanoma and because there is already considerable evidence to suggest the technique in colonic neoplasia may be at its most accurate in germinal disease. In addition, it may already be employed by laparoscopy while solely transluminal means of its deployment are advancing. While the confluence of operative technologies and techniques now coming on-stream has the potential to precipitate a dramatic shift in the paradigm for the management of early stage colonic neoplasia, considerable confirmatory study is required to ensure that oncology propriety and treatment efficacy is maintained so that patient benefit may be maximized.

Sentinel node biopsy for the individualization of surgical strategy for cure of early-stage colon cancer

INTRODUCTION

The requirement for nodal analysis currently confounds the oncological propriety of focused purely endoscopic resection for early-stage colon cancer and complicates the evolution of innovative alternatives such as natural orifice transluminal endoscopic surgery (NOTES) and its hybrids. Adjunctive sentinel node biopsy (SNB) deserves consideration as a means of addressing this shortfall.

METHODS

Data from two prospectively maintained databases established for multicentric studies of SNB in colon cancer that employed similar methodologies were pooled to establish technique potency selectively in T1/T2 disease (both overall and under optimized conditions) and to project potential clinical impact.

RESULTS

Of 891 patients with T1-4, M0 intraperitoneal colon cancer, 225 had T1/T2 disease. Sentinel nodes were either not found or were falsely negative in 18 patients with T1/T2 cancers (8%) as compared with 17% (112/646) in those with T3/T4 disease (P = 0.001). Negative predictive value (NPV) in the former exceeded 95%, while sensitivity [including immunohistochemistry (IHC)] was 81%. In the 193 patients with T1/T2 disease recruited from those centers contributing >22 patients, sensitivity was 89% and NPV 97%. Thus, in this cohort, SNB could have correctly prompted localized resection (obviating en bloc mesenteric dissection) in 75% (144) of patients, including 59 with T1 lesions potentially amenable to intraluminal resection alone as their definitive treatment. Forty-four patients (23.4%) would still have conventional resection, leaving three patients (1.6% overall) understaged (11% false-negative rate).

CONCLUSION

These findings support the further investigation of SNB as oncological augment for localized resective techniques. Specific prospective study should pursue this goal.

Supplementation of endoscopic submucosal dissection with sentinel node biopsy performed by natural orifice transluminal endoscopic surgery (NOTES) (with video)

BACKGROUND

Endoscopic submucosal dissection (ESD) is proving to be effective for the resection of selected early gastric and colon cancers. Its application and appropriateness could be extended if a means of determining lymphatic dissemination without recourse to a conventional operation could be provided.

OBJECTIVE

To demonstrate the feasibility of companion sentinel node biopsy (SNB) by natural orifice transluminal endoscopic surgery (NOTES) concurrent with intraluminal ESD in both the sigmoid colon and stomach.

DESIGN

Acute porcine model.

INTERVENTION

Arbitrarily selected mucosal foci were targeted for combined NOTES-SNB and ESD in the sigmoid and stomach of 2 separate anesthetized animals. NOTES peritoneal access was obtained either transgastrically or transvaginally. A second intraluminal endoscope was passed either orally or rectally, as appropriate, to perform submucosal injection for lymphatic mapping under direct vision of the NOTES endoscope. This endoscope then identified the first-order draining (sentinel) nodes and allowed their excisional biopsy. The sigmoid was retracted by magnetic assistance as required, while torque of an intraluminal gastroscope manipulated the stomach. After retrieval of the nodes, 1-cm and 1.5-cm specimens were resected from the sigmoid and stomach, respectively, by conventional ESD. At procedure end, necropsy was performed.

RESULTS

All sentinel nodes were identified, underwent biopsy, and were retrieved intact. ESD was subsequently readily performed without complication. SNB completeness and ESD quality were confirmed postprocedure.

LIMITATIONS

Experimental model with limited sample size.

CONCLUSIONS

Although not yet appropriate for human use, this proposal merits serious consideration as a potential means of augmenting the effectiveness and appropriateness of ESD techniques for GI neoplasia.