Management of Malignant Adenomas

The Outcome of Local Excision of Rectal Adenomas with High-Grade Dysplasia by Transanal Endoscopic Microsurgery: A Single-Center Experience

Background: Local excision by transanal endoscopic microsurgery (TEM) is considered an acceptable treatment for rectal adenomas with high-grade dysplasia (HGD). This study aims to assess the likelihood of harboring an invasive carcinoma in preoperatively diagnosed HGD polyps and evaluate the risk factors for tumor recurrence in patients with final HGD pathology. Methods: Data from patients who underwent TEM procedures for adenomatous lesions with HGD from 2005 to 2018 at the Rabin Medical Center, Hasharon Hospital, were analyzed. Collected data included patient demographics, preoperative workup, tumor characteristics and postoperative results. Follow-up data including recurrence assessment and further treatments were reviewed. The analysis included two subsets: preoperative pathology of HGD (sub-group 1) and postoperative final pathology of HGD (sub-group 2) patients. Results: Forty-five patients were included in the study. Thirty-six patients had a preoperative diagnosis of HGD, with thirteen (36%) showing postoperative invasive carcinoma. Thirty-two patients had a final pathology of HGD, and three (9.4%) experienced tumor recurrence. Large tumor size (>5 cm) was significantly associated with recurrence (p = 0.03). Conclusions: HGD rectal polyps are associated with a significant risk of invasive cancer. Tumor size was a significant factor in predicting tumor recurrence in patients with postoperative HGD pathology. The TEM procedure is an effective first-line treatment for such lesions.

Molecular and cellular pathways in colorectal cancer: apoptosis, autophagy and inflammation as key players

BACKGROUND

Colorectal carcinogenesis (CRC) is one of the most aggressive forms of cancer, particularly in developing countries. It accounts for the second and third-highest reason for cancer-induced lethality in women and men respectively. CRC involves genetic and epigenetic modifications in colonic epithelium, leading to colon adenocarcinoma. The current review highlights the pathogenic mechanisms and multifactorial etiology of CRC, influenced by apoptosis, inflammation, and autophagy pathways.

METHODS

We have carried out a selective literature review on mechanisms contributing to the pathogenesis of CRC.

RESULTS

Resistance to senescence and apoptosis of the mesenchymal cells, which play a key role in intestinal organogenesis, morphogenesis and homeostasis, appears important for sporadic CRC. Additionally, inflammation-associated tumorigenesis is a key incident in CRC, supported by immune disruptors, adaptive and innate immune traits, environmental factors, etc. involving oxidative stress, DNA damage and epigenetic modulations. The self-digesting mechanism, autophagy, also plays a twin role in CRC through the participation of LC3/LC3-II, Beclin-1, ATG5, other autophagy proteins, and Inflammatory Bowel Disease (IBD) susceptibility genes. It facilitates the promotion of effective surveillance pathways and stimulates the generation of malignant tumor cells. The autophagy and apoptotic pathways undergo synergistic or antagonistic interactions in CRC and bear a critical association with IBD that results from the pro-neoplastic effects of persistent intestinal inflammation. Conversely, pro-inflammatory factors stimulate tumor growth and angiogenesis and inhibit apoptosis, suppressing anti-tumor activities.

CONCLUSION

Hence, research attempts for the development of potential therapies for CRC are in progress, primarily based on combinatorial approaches targeting apoptosis, inflammation, and autophagy.

Malignant colon polyps: predicting lymph node metastasis following endoscopic excision

AIM

The risk of lymph node metastasis (LNM) of malignant colon polyps (MCPs) is partly estimated by histologic features of the sampled polyp. However, the routinely available histologic data is limited to tumor grade and status of lymphovascular invasion (LVI).

METHODS

The NCDB for colon cancer 2004-2018 was utilized. Patients with pT1Nx adenocarcinoma arising in a polyp and undergoing partial colectomy with ≥ 12 retrieved nodes were selected. NCDB 2004-2017 was used as a training cohort to develop two scoring systems based on a multivariable regression for predictors of LNM including clinical characteristics, grade, and LVI: a nomogram scoring system (NSS) and a simplified scoring system (SSS). These models were internally validated using NCDB 2018 to calculate precision metrics for each model.

RESULTS

Six thousand sixty-nine patients were selected in the training cohort. 64.5% of MCPs were in the sigmoid, and LNM rate was 11.2%. Multivariable regression identified younger age, females, hindgut location, higher grade, and LVI as significant predictors of LNM. LNM risk was 1.2% when all unfavorable predictors were absent and exceeded 10% when NSS > 70 or SSS ≥ 3. In the 2018 validation cohort, 723 patients were scored per NSS and SSS, and the negative predictive value for both was 96%.

CONCLUSION

Estimating LNM risk in MCPs by applying clinical characteristics along with limited histologic data can help inform decision-making when considering formal oncologic resection. The NSS and SSS demonstrated comparable predictability of LNM among pT1Nx MCPs. The models require external validation and may be strengthened by incorporating additional endoscopic and pathologic characteristics.

Factors predicting occurrence and therapeutic choice in malignant colorectal polyps: a study of 13 years of colonoscopic polypectomy

Colorectal carcinoma represents a major cause of mortality and 0.2–12% of resected colonic polyps have malignant cells inside. We performed a retrospective study of patients with resected polyps during a period of 13 years. A total of 905 patients had 2033 polyps removed; 122 polyps (109 patients) had malignant cells. Prevalence of malignant polyps with submucosal invasion was 1.23% and for all polyps with malignant cells was 6%; malignant polyps had a larger size (23.44 mm mean diameter) vs benign polyps (9.63 mm); the risk of malignancy was increased in polyps larger than 10 mm, in lateral spreading lesions and in Paris types 0-Ip, 0-Isp, in sigmoid, descending colon and rectum, in sessile serrated adenoma and traditional serrate adenoma subtypes of serrated lesions and in tubulovillous and villous adenoma. In 18 cases surgery was performed, in 62 patients only colonoscopic follow-up was made and in 35 patients no colonoscopic follow-up was recorded. From initially endoscopic resected polyps, recurrence was noted in seven (11.3%) cases; there was a trend toward association with depth of invasion, piecemeal resection, right and rectum location, sessile and lateral spreading type and pathological subtype. In surgical group, post-therapeutic staging was available in 11 cases; nodal involvement was noted in three (27.27%) cases; none had lymphatic or vascular invasion in endoscopically resected polyps. Four patients with no macroscopic local recurrence underwent surgery with no residual tumor. The rate of metastasis was 16.67% in surgical group and 1.61% in endoscopic group. Evaluation of lymph node (LN) invasion was available for 11 operated patients, with LN invasion (N1) in three patients, local residual tumoral tissue in one patient with incomplete resection and no residual tumor (R0 resection) in four patients with endoscopic resection before surgery.

A perspective on medicinal chemistry approaches towards adenomatous polyposis coli and Wnt signal based colorectal cancer inhibitors

Colorectal cancer (CRC) is one of the major causes of carcinogenic mortality in numbers only after lung and breast cancers. The mutations in adenomatous polyposis coli (APC) gene leads to formation of colorectal polyps in the colonic region and which develop as a malignant tumour upon coalition with patient related risk factors. The protein-protein interaction (PPI) of APC with Asef (A Rac specific guanine nucleotide exchange factor) overwhelms the patient's conditions by rapidly spreading in the entire colorectal region. Most mutations in APC gene occur in mutated cluster region (MCR), where it specifically binds with the cytosolic β-catenin to regulate the Wnt signalling pathway required for CRC cell adhesion, invasion, progression, differentiation and stemness in initial cell cycle phages. The current broad spectrum perspective is attempted to elaborate the sources of identification, development of selective APC inhibitors by targeting emopamil-binding protein (EBP) & dehydrocholesterol reductase-7 & 24 (DHCR-7 & 24); APC-Asef, β-catenin/APC, Wnt/β-catenin, β-catenin/TCF4 PPI inhibitors with other vital Wnt signal cellular proteins and APC/Pol-β interface of colorectal cancer. In this context, this perspective would serve as a platform for design of new medicinal agents by targeting cellular essential components which could accelerate anti-colorectal potential candidates.

Management Considerations for the Surgical Treatment of Colorectal Cancer During the Global Covid-19 Pandemic

Objective:

The COVID-19 pandemic requires to conscientiously weigh “timely surgical intervention” for colorectal cancer against efforts to conserve hospital resources and protect patients and health care providers.

Summary Background Data:

Professional societies provided ad-hoc guidance at the outset of the COVID-19 pandemic on deferral of surgical and perioperative interventions, but these lack specific parameters to determine the optimal timing of surgery.

Methods:

Using the GRADE system, published evidence was analyzed to generate weighted statements for stage, site, acuity of presentation, and hospital setting to specify when surgery should be pursued, the time and duration of oncologically acceptable delays, and when to utilize nonsurgical modalities to bridge the waiting period.

Results:

Colorectal cancer surgeries—prioritized as emergency, urgent with imminent emergency or oncologically urgent, or elective—were matched against the phases of the pandemic. Surgery in COVID-19-positive patients must be avoided. Emergent and imminent emergent cases should mostly proceed unless resources are exhausted. Standard practices allow for postponement of elective cases and deferral to nonsurgical modalities of stage II/III rectal and metastatic colorectal cancer. Oncologically urgent cases may be delayed for 6(–12) weeks without jeopardizing oncological outcomes. Outside established principles, administration of nonsurgical modalities is not justified and increases the vulnerability of patients.

Conclusions:

The COVID-19 pandemic has stressed already limited health care resources and forced rationing, triage, and prioritization of care in general, specifically of surgical interventions. Established guidelines allow for modifications of optimal timing and type of surgery for colorectal cancer during an unrelated pandemic.

Quadruplicate Synchronous Adenocarcinoma of the Colon with Distant Metastases-Long-Term Molecular Follow-Up by KRAS and TP53 Mutational Profiling

Anatomically independent tumor foci represent biologically distinct neoplasias, potentially featured by different progressivity and treatment responsiveness. To demonstrate the biological complexity, a metastatic colon adenocarcinoma patient originally presenting with four independent primary tumors of the right colon half and altogether eight distant metastases was followed by molecular testing. Next-generation sequencing results highlighted the mutational profile of the individual primaries and the dynamics of the different gene variants observed during follow-up. The four primary colon tumors presented with four different KRAS genotypes, one of them with a wild-type and three with pathogenic variants, without overlap. These were the following: c.35G > A; p.Gly12Asp with 40.6% variant allele frequency (VAF); c.34G > T; p.Gly12Cys with 16.2% VAF and c.35G > T; p.Gly12Val with 15.1% VAF. In metastatic tumors, with one exception where no mutation was detected, only the KRAS c.34G > T; p.Gly12Cys mutation could be detected. TP53 gene variants were variable in the primary tumors, with a single dominant variant evolving in the follow-up metastases (c.820G > T; p.Val274Phe). Genetic profiling of individually developing synchronous malignancies uncovers the clonal relations of metastatic tumors. NGS gene panels provide a solution to follow the dynamics of key oncogene variants during the course of the disease and greatly contribute to therapy optimization.

Importance of Resection Margins in the Treatment of Rectal Adenomas by Transanal Endoscopic Surgery

BACKGROUND

Polypectomy is the gold standard for treating colorectal adenomas up to 2 cm in size. For larger lesions, various procedures ranging from endoscopy to transanal surgery can be performed and achieve varying results for en bloc resection and recurrence. There are no clear guidelines for dealing with involved resection margins. We assess the recurrence of rectal adenomas operated using TEM with full-thickness wall excision with or without free resection margins and define optimal endoscopic follow-up.

METHOD

Observational study with prospective data collection, including patients undergoing TEM between 6/2004 and 11/2017, with definitive diagnosis of rectal adenoma. Data on epidemiological, preoperative, surgical, postoperative, pathological, and follow-up variables were recorded. Univariate analysis, follow-up risk function, and multivariate logistic regression analysis were performed to detect risk factors for recurrence.

RESULTS

TEM was indicated in 736 patients; 481 adenomas were identified in the preoperative biopsy, of which 95 were infiltrating adenocarcinomas (19.8%) in the definitive pathology study. With a minimum follow-up of 1 year, 372 patients were included. Pathology study showed free margins in 324 (87%). Recurrences were recorded in 15 patients (4%), up to 18 months in the free margins group and up to 24 months in the involved margins group. Thirteen patients with recurrence (86.6%) were treated with TEM. No predictors of recurrence were found in the multivariate analysis.

CONCLUSION

TEM is the technique of choice for treating rectal adenomas and recurrences, achieving a low relapse rate. Follow-up must be adapted to resection margins and should be extended to 24 months.

Importance of Resection Margins in the Treatment of Rectal Adenomas by Transanal Endoscopic Surgery

BACKGROUND

Polypectomy is the gold standard for treating colorectal adenomas up to 2 cm in size. For larger lesions, various procedures ranging from endoscopy to transanal surgery can be performed and achieve varying results for en bloc resection and recurrence. There are no clear guidelines for dealing with involved resection margins. We assess the recurrence of rectal adenomas operated using TEM with full-thickness wall excision with or without free resection margins and define optimal endoscopic follow-up.

METHOD

Observational study with prospective data collection, including patients undergoing TEM between 6/2004 and 11/2017, with definitive diagnosis of rectal adenoma. Data on epidemiological, preoperative, surgical, postoperative, pathological, and follow-up variables were recorded. Univariate analysis, follow-up risk function, and multivariate logistic regression analysis were performed to detect risk factors for recurrence.

RESULTS

TEM was indicated in 736 patients; 481 adenomas were identified in the preoperative biopsy, of which 95 were infiltrating adenocarcinomas (19.8%) in the definitive pathology study. With a minimum follow-up of 1 year, 372 patients were included. Pathology study showed free margins in 324 (87%). Recurrences were recorded in 15 patients (4%), up to 18 months in the free margins group and up to 24 months in the involved margins group. Thirteen patients with recurrence (86.6%) were treated with TEM. No predictors of recurrence were found in the multivariate analysis.

CONCLUSION

TEM is the technique of choice for treating rectal adenomas and recurrences, achieving a low relapse rate. Follow-up must be adapted to resection margins and should be extended to 24 months.

The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Treatment of Colon Cancer

The American Society of Colon and Rectal Surgeons is dedicated to ensuring high-quality patient care by advancing the science, prevention, and management of disorders and diseases of the colon, rectum, and anus. The Clinical Practice Guidelines Committee is composed of society members who are chosen because they have demonstrated expertise in the specialty of colon and rectal surgery. This committee was created to lead international efforts in defining quality care for conditions related to the colon, rectum, and anus. This is accompanied by developing Clinical Practice Guidelines based on the best available evidence. These guidelines are inclusive and not prescriptive. Their purpose is to provide information on which decisions can be made, rather than to dictate a specific form of treatment. These guidelines are intended for the use of all practitioners, health care workers, and patients who desire information about the management of the conditions addressed by the topics covered in these guidelines. It should be recognized that these guidelines should not be deemed inclusive of all proper methods of care or exclusive of methods of care reasonably directed to obtaining the same results. The ultimate judgment regarding the propriety of any specific procedure must be made by the physician in light of all the circumstances presented by the individual patient.

The Difficult Colorectal Polyp

Difficult colorectal polyps represent lesions that pose a challenge to traditional endoscopic snare polypectomy. These polyps have historically been managed by surgical resection. Currently, several less invasive options are available to avoid colectomy. Repeat colonoscopy and snare polypectomy by an expert endoscopist, endoscopic mucosal resection, endoscopic submucosal dissection, and combined endoscopic and laparoscopic surgery have been developed to remove difficult polyps without the need for formal surgical resection. Patients with rectal polyps have the advantage of additional transanal minimally invasive techniques to enhance their resectability. Today, most colorectal polyps can be managed without the need for formal surgical resection.