Colorectal neoplasms in melanosis coli: a survey in Japan and a worldwide meta-analysis

Colonoscopic Resolution of Melanosis Coli After Cessation of Senna Laxative Use

Melanosis coli occurs with the administration of stimulant laxatives for the relief of constipation. However, the duration of macroscopic improvement of melanosis coli after discontinuation of anthracene laxatives is not well understood. We describe the case of an 81-year-old female diagnosed with melanosis coli via colonoscopy who had been taking senna laxatives for 5 years. Seven months after cessation of senna laxatives, colonoscopy showed no melanosis coli in the colon. This impressive report describes the observation of melanosis coli with colonoscopy; 7 months after the withdrawal of senna stimulant laxatives, melanosis coli resolved.

Review article: do stimulant laxatives damage the gut? A critical analysis of current knowledge

Stimulant laxatives are well established as first- or second-line treatments for constipation and although they have a reliable therapeutic effect, alleged safety concerns still exist, particularly with long-term use. The potential harmful effects on the gastrointestinal system (including carcinogenicity) of the long-term use of diphenylmethane [bisacodyl, sodium picosulfate (SPS)] and senna stimulant laxatives were assessed in a comprehensive review of the publications identified in literature searches performed in PubMed and Embase up to and including June 2023. We identified and reviewed 43 publications of interest. While stimulant laxatives at supratherapeutic doses have been shown to cause structural alterations to surface absorptive cells in animals and humans, these effects are reversible and not considered clinically relevant. No formal long-term studies have demonstrated morphological changes in enteric neural elements or intestinal smooth muscle with bisacodyl or SPS in humans. Furthermore, there is no convincing evidence that stimulant laxatives are associated with the development of colon cancer, and in fact, chronic constipation itself has been reported to potentially increase the risk of colon cancer, therefore, the use of stimulant laxatives might reduce this risk. Many studies suggesting a possible harmful effect from laxatives were limited by their failure to consider confounding factors such as concomitant neurological disease, metabolic disorders, and age. These findings highlight the lack of evidence for the harmful effects of laxatives on the colon, and thus, the benefits of treatment with stimulant laxatives, even in the long-term, should be reconsidered for the management of patients with constipation.

Review on melanosis coli and anthraquinone-containing traditional Chinese herbs that cause melanosis coli

Backgrounds: The incidence of melanosis coli (MC) has gradually increased annually, attracting significant attention and efforts into this field. A potential risk for MC is the long-term use of anthraquinone laxatives in patients with constipation. Most traditional cathartic drugs are made from herbs containing anthraquinone compounds. This review aims to provide guidance for the application of traditional Chinese herbs containing anthraquinones for physicians and researchers. Materials and methods: We reviewed risk factors and pathogenesis of MC, and natural anthraquinones isolated from TCM herbs. We searched Pubmed and CNKI databases for literature related to MC with keywords such as"traditional Chinese medicine", "Chinese herbs", "anthraquinones", and "melanosis coli". The literature is current to January 2023 when the searches were last completed. After the literature retrieval, the TCM herbs containing anthraquinones (including component identification and anthraquinone content determination) applied in clinical were selected. According to the collected evidence, we provide a list of herbs containing anthraquinones that could cause MC. Results: We identified 20 herbs belonging to 7 families represented by Polygonaceae, Fabaceae, Rhamnaceae, and Rubiaceae, which may play a role in the pathogenesis of MC. Among these, the herbs most commonly used include Dahuang (Rhei Radix et Rhizome), Heshouwu (Radix Polygoni Multiflori), Huzhang (Rhizoma Polygoni Cuspidati), Juemingzi (Semen Cassiae), Luhui (Aloe) and Qiancao (Rubiae Radix et Rhizoma). Conclusion: Due to a lack of awareness of the chemical composition of TCM herbs, many patients with constipation and even some TCM physicians take cathartic herbal remedies containing abundant anthraquinones to relieve defecation disturbances, resulting in long-term dependence on these herbs, which is potentially associated with most cases of MC. When such treatments are prescribed, TCM physicians should avoid long-term use in large doses to reduce their harm on colonic health. Individuals who take healthcare products containing these herbs should also be under the supervision of a doctor.

Laparoscopic total colectomy with ileorectal anastomosis and subtotal colectomy with antiperistaltic cecorectal anastomosis for slow transit constipation

To investigate the clinical efficacy of laparoscopic total colectomy with ileorectal anastomosis (TC-IRA) and laparoscopic subtotal colectomy with antiperistaltic cecorectal anastomosis (SC-ACRA) on adults with slow transit constipation (STC). One hundred and three patients with STC were assigned to the TC-IRA group (n = 53) and the SC-ACRA group (n = 50). The clinical data were analyzed. The surgery was successful in all patients (100%). Significantly (P = 0.03) more patients took anti-laxatives during hospitalization in the TC-IRA than the SC-ACRA group (39.62% vs. 20.00%). Abdominal pain and distension was present in 33.96% and 32.00% patients in the TC-IRA and SC-ACRA group, respectively, which decreased insignificantly (P > 0.05) to 18.87% and 18.00% 24 months after surgery, respectively. The postoperative Wexner and gastrointestinal quality of life (GIQLI) scores were not significantly different (P > 0.05) at all times after surgery in both groups. The defecation frequency decreased in both groups, and the average defecation frequency was significantly (P < 0.05) higher in the TC-IRA than the SC-ACRA group (3.91 ± 1.23 vs. 3.14 ± 1.15 times/day) at 3 months. Three months after surgery, significantly (P < 0.05) fewer patients were satisfied with defecation frequency in the TC-IRA than the SC-ACRA group (29 vs. 37 patients), whereas the number of patients who were willing to choose the same procedure again was not significantly (P > 0.05) different between the two groups. The WIS score of patients was significantly (P = 0.035) higher in the TC-IRA than the SC-ACRA group (6 vs. 5) 3 months later. TC-IRA and SC-ACRA are both safe and effective for adult slow transit constipation, and can significantly improve the quality of life of patients. Even though SC-ACRA has better early defecation frequency, postoperative antidiarrheal application and satisfaction, the long-term follow-up effects are similar.

Melanosis coli: a contrast effect or an oncogenic effect? A large-scale retrospective cohort study

BACKGROUND

Melanosis coli is characterized by brown mucosa with pigmentation. Studies have showed an increased adenoma detection rate in melanosis patients, whether it is caused by a contrast effect or an oncogenic effect is still controversial. The detection of serrated polys in melanosis patients remains unknown.

AIMS

The study aimed to clarify the correlation of adenoma detection rate with melanosis coli and discuss outcomes in less-experienced endoscopists. Serrated polyp detection rate was also been investigated.

METHODS

A total of 2150 patients and 39,630 controls were enrolled. A propensity score matching method was used to balance covariates between the two groups. The detection of polyps, adenomas, serrated polyps, and their features was analyzed.

RESULTS

The polyp detection rate (44.65% vs 41.01%, P = 0.005) and adenoma detection rate (30.34% vs 23.92%, P < 0.001) were significantly higher, and the serrated polyp detection rate (0.93% vs 1.58%, P = 0.033) was significantly lower in melanosis coli. The percentage of low-risk adenomas (44.60% vs 39.16%, P < 0.001) and polyps with 6 to 10 mm in size (20.16% vs 16.21%, P < 0.001) were higher in melanosis coli. The detection of large serrated polyps was lower (0.11% vs 0.41%, P = 0.026) in melanosis coli.

CONCLUSION

Melanosis coli correlates with an increased adenoma detection rate. The detection of large serrated polyps was lower in melanosis patients. Melanosis coli may not be considered a precancerous lesion.

Severe grade of melanosis coli is associated with a higher detection rate of colorectal adenoma

The severity and distribution of melanosis coli differ among individuals, and the related factors remain unknown. Additionally, their clinical implications have not been sufficiently demon-strated. Thus, we aimed to detect clinical factors related to the severity and range of melanosis coli and elucidate the associations between the grade, location, and detection rate of colorectal neoplasms. Colonoscopy cases performed at our institution from January 2011 to February 2021 were included. Melanosis coli was classified into mild and severe grades. Clinical characteristics and neoplasm detection rates were compared between the mild and severe MC groups and between the right-sided and whole-colon melanosis coli groups. Overall, 236 MC (mild, n = 143; severe, n = 93) cases, of which 50 were right-sided, 5 were left-sided, and 181 were whole-colon melanosis coli cases, were enrolled. The proportion of anthranoid users was higher in the severe melanosis coli group than in the mild melanosis coli group. The adenoma detection rate was higher in the severe melanosis coli and whole-colon melanosis coli groups. The prevalence of neoplasms measuring 5-9 mm and >9 mm was higher in the severe melanosis coli group (p<0.01 and p = 0.04). Severe melanosis coli due to anthranoid usage is associated with colorectal adenoma development.

Increased Colonic Fluorodeoxyglucose Uptake in Melanosis Coli-A Case Series of Three Patients

We report 3 Japanese cases with increased colonic 18-fluorodeoxyglucose (FDG) uptake in association with melanosis coli. Case 1: A 56-year-old woman received 18-FDG positron emission tomography (PET) for comprehensive medical checkup. Case 2: A 79-year-old man received FDG-PET for follow-up evaluation for intestinal cancer. Case 3: A 51-year-old woman received FDG-PET for medical checkup. Each showed increased cecal and/or ascending colonic uptake without any colonic wall changes. Colonoscopy detected melanosis coli where FDG uptake was demonstrably increased. Neither malignancy nor inflammatory response was confirmed. Succeeding follow-ups showed neither malignant nor inflammatory lesions in any of the patients.

Melanosis coli: A factor not associated with histological progression of colorectal polyps

OBJECTIVE

In this study we aimed to investigate the association of melanosis coli (MC) and the colorectal polyp detection rate (PDR).

METHODS

In all, 1104 MC patients and 62 181 non-MC participants were enrolled. And 2208 controls were matched by participants' age and gender, and quality of bowel preparation using the propensity score matching (PSM) method. Additionally, 490 polyps in MC and 980 in controls matched by age and gender, and size and location of polyps were analyzed. The association of PDR and pathological features of polyps with MC were also analyzed.

RESULTS

MC patients showed a higher PDR (44.3% vs 39.3%, P = 0.006) and detection rate of low-grade adenoma (45.4% vs 36.7%, P = 0.002) but fewer large polyps (≥10 mm) (18.8% vs 26.9%, P = 0.001), fewer polyps in the left colon (33.5% vs 40.0%, P = 0.018), and a lower detection rate of advanced adenoma/adenocarcinoma (17.4% vs 24.3%, P = 0.003) than the matched controls. On multivariate logistic regression analysis, MC was independently associated with an increased PDR (odds ratio 1.184, 95% confidence interval 1.045-1.343, P = 0.008). Analysis targeting polyps showed that there were significant differences in age, gender, location, and pathology (P < 0.001) between polyps with and without MC. However, after adjusting for participants' age and gender, size and location of polyps, there was no difference between the two groups in pathology (P = 0.635).

CONCLUSION

MC is independently associated with increased colorectal PDR, but not with histological progression of polyps.