Melanosis coli in patients with colon cancer

Case report: Melanosis coli combined with colon cancer, causality or coincidence?

The habitual use of laxative containing anthraquinone glycosides is considered to be the main cause of melanosis coli (MC). In the past, most scholars considered MC to be a benign and reversible disease. However, new evidence has emerged that MC may increase the risk of colon cancer. Here, we report a case of a 48-year-old woman diagnosed with MC and colon cancer. Through a literature review of previous basic and clinical studies, we summarize existing evidence that reveals the possible association between MC and colon cancer. Although this case cannot establish causality between MC and colon cancer, a high level of clinical vigilance for occurrence of colon cancer in patients with MC should be maintained.

Pharmacology, Toxicology, and Metabolism of Sennoside A, A Medicinal Plant-Derived Natural Compound

Sennoside A (SA) is a natural dianthrone glycoside mainly from medicinal plants of Senna and Rhubarb, and used as a folk traditional irritant laxative and slimming health food. Accumulating evidences suggest that SA possesses numerous pharmacological properties, such as laxative, anti-obesity, hypoglycemic, hepatoprotective, anti-fibrotic, anti-inflammatory, anti-tumor, anti-bacterial, anti-fungal, anti-viral, and anti-neurodegenerative activities. These pharmacological effects lay the foundation for its potential application in treating a variety of diseases. However, numerous published studies suggest that a long-term use of SA in large doses may have some adverse effects, including the occurrence of melanosis coli and carcinogenesis of colon cancer, thereby limiting its clinical use. It remains to be established whether SA or its metabolites are responsible for the pharmacological and toxicity effects. In this review, the latest advances in the pharmacology, toxicology, and metabolism of SA were summarizedbased on its biological characteristics and mechanism.

Melanosis coli in a peritoneal dialysis patient: a case report

BACKGROUND

Patients who undergo peritoneal dialysis (PD) are at risk of gut bacteria translocation leading to peritonitis when there is chronic diarrhea. Chronic diarrhea is defined as any course of diarrhea that lasts at least 4 weeks, which can be continuous or intermittent. Chronic diarrhea of any duration may cause dehydration, electrolyte imbalance, and life-threatening hypovolemic shock. In PD patients, excessive ultrafiltration from the exchanges, combined with severe gastrointestinal loss, may cause hypovolemic shock, electrolyte imbalance, and metabolic acidosis. There are multiple causes of chronic diarrhea in PD patients including infective causes, mitotic lesions, and rarely the regular and excessive use of laxatives, which is a diagnosis of exclusion.

CASE PRESENTATION

We report a case of Melanau lady with chronic diarrhea secondary to laxative usage in a patient being treated with automated peritoneal dialysis (APD). The patient went into hypovolemic shock, but luckily did not contract peritonitis. A colonoscopy revealed brown to black discoloration of the colon, a feature suggestive of melanosis coli. A biopsy of the intestine further confirmed the diagnosis by histopathological examination. Withdrawal of laxatives and the introduction of probiotics improved the symptoms tremendously.

CONCLUSIONS

The chronic use of laxatives in PD patients can potentially lead to a devastating problem; thus, the management team must monitor treatment commencement appropriately.

Pseudomelanosis coli, its relation to laxative use and association with colorectal neoplasms: A comprehensive review

Pseudomelanosis coli is historically associated with anthraquinone laxatives and is often used as a surrogate marker for chronic laxative use. The opioid epidemic has seen an increase in laxative use for chronic constipation. Anthraquinone laxatives have demonstrated tumorigenic potential in animal studies due to their apoptotic effects on colonic epithelial cells. Colorectal cancer is associated with significant mortality and morbidity worldwide. Human studies have not shown a significant correlation between anthraquinone laxative use, pseudomelanosis coli, and colorectal carcinoma. The characteristic pigmentation of pseudomelanosis also appears to be absent macroscopically and on histology of neoplastic epithelium. However, there appears to be a slightly higher risk of adenoma development. This has been attributed to a higher polyp detection rate during endoscopy on account of the color contrast between the polyp against a darker background of pseudomelanosis.

Retrospective study on melanosis coli as risk factor of colorectal neoplasm: a 3-year colonoscopic finding in Zhuhai Hospital, China

BACKGROUND

Melanosis coli (MC) is a colonoscopic finding in which the colonic mucosa appears darkly pigmented than usual and generally caused by extended anthranoid laxative use.

METHODS

We performed a retrospective study at Zhuhai Hospital to investigate the risk of MC for CR neoplasm development. A total of 12,776 patients who underwent colonoscopy from 2013 to 2016 including 250 diagnosed with MC and 500 controls were included in this study. Odds ratios (OR) and 95% confidence intervals (95%CI) for associations of MC with CR neoplasm detection were estimated using univariate and multivariable multinomial logistic analyses for known risk factors.

RESULTS

The presence of MC was associated with a significant increase in the CR neoplasm detection rate compared with controls (OR = 1.701, 95% CI = 1.252-2.31; P = 0.001). The effect was also observed in different tumor sites, age group, gender, and lifestyle. Using univariate multinomial analysis, patients with MC were significantly associated with both hyperplastic polyp (OR = 2.069, 95% CI = 1.253-3.415; P = 0.005) and low-grade (LG) adenoma (OR = 1.585, 95% CI = 1.115-2.254; P = 0.010). However, there was no significant difference with adenocarcinoma (OR = 1.701, 95% CI = 0.990-2.924; P = 0.055). Using multivariate multinomial analysis, MC patients remained associated with increased hyperplastic polyp (OR = 1.870, 95% CI = 1.119-3.125; P = 0.017) and LG adenoma (OR = 1.474, 95% CI = 1.027-2.114; P = 0.035), but not adenocarcinoma (OR = 1.620, 95% CI = 0.914-2.871; P = 0.098). A significant increase in CR neoplasm rate was observed with drinker, smoker, and elderly patients but not with gender.

CONCLUSION

Patients with MC were more likely to have both hyperplastic polyp and LG adenoma. If confirmed, such findings could suggest the discontinuation of anthranoid laxative use particularly in the elderly.

Association between anthraquinone laxatives and colorectal cancer: protocol for a systematic review and meta-analysis

INTRODUCTION

Products containing anthraquinones (AQ) are mainly used as laxatives and have several biological effects. Long-term use of AQ laxatives is associated with an increased risk of serious adverse events (AEs), such as colorectal cancer (CRC). We will systematically synthesize the evidence on the potential association between the use of AQ laxatives and the risk of CRC.

METHODS AND ANALYSIS

We will search MEDLINE, Embase, Scopus, the Cochrane Library, Google Scholar, and Clinicaltrials.gov. To avoid missing any relevant studies, we will search the bibliographies of retrieved papers and recent reviews in the field. Interventions will include products containing oral AQ laxatives, in particular, those derived from rhubarb, senna, cascara, buckhorn, and aloe. Two review authors will independently screen title, abstract, and full texts and will independently extract data from included studies. The primary outcome is the number of participants diagnosed with CRC, while the secondary outcome will be cases of melanosis coli. We will also consider all other AEs reported in the included studies, in particular, intestinal bleeding, alterations of gastrointestinal motility, and potential for dependence. When possible and appropriate, for each outcome, a meta-analysis will be performed.

DISCUSSION

This protocol is prepared in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols guidelines. The protocol gives an insight into the scope and parameters for the systematic review to be carried out.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019125414.

Quantitative Analysis of Melanosis Coli Colonic Mucosa Using Textural Patterns

Melanosis coli (MC) is a disease related to long-term use of anthranoid laxative agents. Patients with clinical constipation or obesity are more likely to use these drugs for long periods. Moreover, patients with MC are more likely to develop polyps, particularly adenomatous polyps. Adenomatous polyps can transform to colorectal cancer. Recognizing multiple polyps from MC is challenging due to their heterogeneity. Therefore, this study proposed a quantitative assessment of MC colonic mucosa with texture patterns. In total, the MC colonoscopy images of 1092 person-times were included in this study. At the beginning, the correlations among carcinoembryonic antigens, polyp texture, and pathology were analyzed. Then, 181 patients with MC were extracted for further analysis while patients having unclear images were excluded. By gray-level co-occurrence matrix, texture patterns in the colorectal images were extracted. Pearson correlation analysis indicated five texture features were significantly correlated with pathological results (p < 0.001). This result should be used in the future to design an instant help software to help the physician. The information of colonoscopy and image analystic data can provide clinicians with suggestions for assessing patients with MC.

Gender, age, and concomitant diseases of melanosis coli in China: a multicenter study of 6,090 cases

BACKGROUNDS AND AIMS

Melanosis coli (MC) is a noninflammatory, benign, and reversible colonic disorder, but its detection rates in China are unclear. We therefore aimed to analyze the epidemiological characteristics of MC in China.

METHODS

We assessed the detection rates, associated factors and concomitant diseases of MC in the patients who underwent colonoscopy at eight medical centers across five regions of China between January 2006 and October 2016. All data were procured from the electronic database established at each participating institutions.

RESULTS

Among the 342,922 included cases, MC was detected in 6,090 cases (detection rate = 1.78%, 95% confidence interval, 1.73%-1.82%) at a mean age of 60 years. The detection rate gradually increased yearly, and along with the increasing age regardless of gender, while a rapid increase presented in the patients ≥60 years of age (0.58% for ≤25 years, 1.22% for 25-59 years, and 3.19% for ≥60 years). The detection rate was higher in females than in males; however, the rate of per-year increase was higher in males than in females at age of ≥60 years, which was 1.85-fold of that in females. Among cancer, polyp, inflammation, and diverticula, polyp was the most common concomitant disease of MC and identified in 41.72% of MC patients.

CONCLUSIONS

MC detection rates were increased annually and elevated in older patients, particularly in male patients. Males in the elderly population of ≥60 years were most likely to have MC. Colonic polyp is the most common concomitant disease of MC.