Synchronous polypectomy during endoscopic diagnosis of colorectal cancer - is the risk of tumour implantation at the polypectomy site significant?

Risk of metachronous colorectal cancer associated with polypectomy during endoscopic diagnosis of colorectal cancer

BACKGROUND AND AIM

There are conflicting reports regarding the risk of metachronous colorectal cancer (CRC) subsequent to colonoscopy with polypectomy or biopsy performed concurrently with diagnostic biopsies for CRC. We aimed to establish the 5-year risk of CRC in patients who had synchronous polypectomy or biopsies during the colonoscopy at which CRC was diagnosed.

METHODS

This is a single-centre retrospective case-control study of adults who underwent surgical resection for CRC over a 2-year period (January 2016 to December 2017). Colonoscopy details of interest were the location of the CRC, polypectomy and non-CRC biopsy sites. In patients with CRC at index colonoscopy, we sought associations between the occurrence of metachronous CRC and the sites from which endoscopic specimens had been obtained.

RESULTS

Our study population comprised 225 patients with a median (IQR) age of 71 (60-77) years. Polypectomy or biopsy at a non-CRC site had been performed during the index colonoscopy in 108 patients (48%), including 83 (37%) polypectomies outside the surgical resection field. There were 8 (3.6%) metachronous CRCs: 1 (0.4%) at the site of endoscopic mucosal resection for a 15-mm sessile serrated lesion, 3 (1.3%) anastomotic site CRCs and 4 (1.8%) at other sites within the colon. There was no significant difference in the prevalence of metachronous CRC in patients who underwent polypectomy/biopsy at the index colonoscopy compared with those who did not (1.9% vs. 5.1%, p = 0.283).

CONCLUSION

There was no significant increased risk of metachronous CRC subsequent to synchronous polypectomy or biopsy during the colonoscopy at which CRC was diagnosed.

Biopsy of Non-tumor Sites After Biopsy of a Colorectal Cancer is not Associated With Metachronous Cancers: A Case-control Study

BACKGROUND & AIMS

Recent research has demonstrated biologic plausibility for iatrogenic tumor seeding via colonoscopy as a cause of metachronous colorectal cancers (CRC). This study evaluated the association between biopsy of non-tumor sites after CRC biopsy and risk of metachronous CRC in a large community-based health care organization.

METHODS

This was a retrospective case-control study of adults with an initial CRC diagnosed by colonoscopy between January 2006 and June 2018 who underwent curative resection. Cases developed a second primary (metachronous) CRC diagnosed 6 months to 4 years after the initial CRC, and were matched by age, sex, diagnosis of inflammatory bowel disease, race, and ethnicity with up to 5 controls without a second CRC diagnosis. The exposure was biopsy in the colonic segment of the metachronous CRC (or corresponding segment in controls) after tumor biopsy, ascertained with blinding to case status. Associations were evaluated using conditional logistic regression and adjusted for potential cofounders.

RESULTS

Among 14,119 patients diagnosed with an initial CRC during colonoscopy, 107 received a second CRC diagnosis. After exclusions for recurrent or synchronous CRC, 45 cases and 212 controls were included. There was no significant association between biopsy of non-tumor sites after initial CRC biopsy and risk of metachronous CRC in the segment of the additional biopsy site (adjusted odds ratio, 2.29; 95% confidence interval, 0.77-6.81).

CONCLUSIONS

Metachronous cancers are not significantly associated with biopsy of non-tumor sites after biopsy of the primary cancer. Although the sample size does not allow definite exclusion of any association, these findings do not support iatrogenic tumor seeding as a common risk factor for metachronous CRC.

Left Perforated Colonic Tumor with Synchronous Locally Advanced Right Colonic Tumor

Colorectal cancer is one of the most common malignant neoplasms worldwide. Overall mortality is 33%. Synchronous colorectal cancer refers to more than one malignant tumor detected in different segments of the colon, simultaneously or within 6 months of initial diagnosis. The development of colorectal cancer is a multistep process that originates with a genetic mutation leading to a malignant phenotype and generating a growth advantage. Colorectal cancer presents up to 16% of hypermutations, of which 75% are characterized by microsatellite instability which in turn leads to poorer cell differentiation. Patients with synchronous tumors appear to have a higher proportion of microsatellite instability than patients with single tumors. The clinical case of a 35-year-old man with a perforated left colon tumor and a locally advanced synchronous tumor of the right colon and signs of acute abdomen is presented. The treatment should be based on the location of the synchronous tumors, stage at the time of approach, and the patient's condition. However, when faced with a complication secondary to colonic cancer, adhering to the principles of oncological surgery can be overcome by the nature of the emergency.

Implantation metastasis from sigmoid colon cancer to rectal anastomosis proved by whole exome sequencing and lineage inference for cancer heterogeneity and evolution analysis: Case report and literature review

It was estimated that 70% of patients with colorectal cancer were found to have viable exfoliated malignant cells in adjacent intestinal lumen. Exfoliated malignant cells had been reported to implant on raw surfaces, such as polypectomy site, anal fissure, anal fistula, hemorrhoidectomy wound, and anastomotic suture line. Tumors at anastomosis could be classified into four groups: local recurrence, local manifestation of widespread metastasis, metachronous carcinogenesis, and implantation metastasis. However, all of the previous studies only reported the phenomena of implantation metastasis at anastomosis. No study had proved the origin of anastomotic metastasis by genomic analysis. In this study, a 43-year-old woman presented with persistent hematochezia was diagnosed as having severe mixed hemorrhoids. She was treated by procedure for prolapse and hemorrhoids (PPH), without receiving preoperative colonoscopy. Two months later, she was found to have sigmoid colon cancer by colonoscopy due to continuous hematochezia and received radical sigmoidectomy. Postoperative histological examination confirmed the lesion to be a moderately differentiated adenocarcinoma (pT3N1M0). Six months later, she presented with hematochezia again and colonoscopy revealed two tumors at the rectal anastomosis of PPH. Both tumors were confirmed to be moderately differentiated adenocarcinoma without lymph node and distant metastasis and were finally removed by transanal endoscopic microsurgery (TEM). Pathological examination, whole exome sequencing (WES), and Lineage Inference for Cancer Heterogeneity and Evolution (LICHeE) analysis demonstrated that the two tumors at the rectal anastomosis were probably implantation metastases arising from the previous sigmoid colon cancer. This is the first study to prove implantation metastasis from colon cancer to a distal anastomosis by WES and LICHeE analysis. Therefore, it is recommended to rule out colorectal cancer in proximal large bowel before performing surgery with a rectal anastomosis, such as PPH and anterior resection. For patients with a suspected implanted tumor, WES and LICHeE could be used to differentiate implantation metastasis from metachronous carcinogenesis.

Cutaneous Stomal Recurrence of Colorectal Cancer After Curative Rectal Cancer Surgery - A Case Report and Systematic Review

BACKGROUND/AIM

Stomal metastases from a primary rectal adenocarcinoma are rare, therefore, clear guidelines on treatment options are limited. We performed a systematic review including a case report on this subject with the primary objective of identifying the total number of cases in the literature. The secondary objective was to assess median survival.

MATERIALS AND METHODS

A 59-year-old woman presented to our institution with anal incontinence to mucus leakage. Flexible sigmoidoscopy identified a carpet adenoma from the dentate line to the rectosigmoid junction. An abdomino-perineal resection (APR) was performed using the transanal total mesorectal excision technique (TaTME). No adjuvant chemotherapy was offered. Twenty-one months following the operation a stomal recurrence was identified. Palliative radiotherapy was commenced and the patient is alive 6 months later with no visible recurrence at the site of the stoma. A systematic review was performed in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines.

RESULTS

The systematic review identified 19 individual cases of either metachronous or true metastatic recurrence, including our own case. Median survival was 30 months in the 8 cases where further treatment was offered and accepted.

CONCLUSION

Stomal metastases or metachronous colorectal cancer is uncommon. The causes for this pattern of spread are not clear. Long-term survival from cutaneous recurrence is generally poor. For carefully selected patients, redo surgery is an option with satisfactory results.

Analysis of Fusobacterium nucleatum and Streptococcus gallolyticus in saliva of colorectal cancer patients

Aim: The aim of the study was to examine the prevalence and amount of Fusobacterium nucleatum (Fn), Porphyromonas gingivalis (Pg) and Streptococcus gallolyticus (Sg) in the saliva of colorectal cancer (CRC) patients and controls. Methods: PCR analyses performed in 71 CRC patients and 77 controls. Results: Saliva samples of patients had higher amounts of Fn (p = 0.001) and Sg (p < 0.001) compared with controls. Amount of Fn and Sg were lower in the microsatellite instability (+) group. Evaluation of salivary Sg amount by receiver operating characteristics analysis found to have diagnostic value for CRC (AUC: 0.84, 95% CI: 0.72-0.96). Conclusion: We found higher amounts of Fn and Sg in the saliva of CRC patients. Salivary Sg could helpful in distinction of CRC.