Metachronous colorectal cancer following segmental or extended colectomy in Lynch syndrome: a systematic review and meta-analysis

Effect of genetic profiling on surgical decisions at hereditary colorectal cancer syndromes

Hereditary colorectal cancer syndromes, such as Lynch syndrome and familial adenomatous polyposis (FAP), present significant clinical challenges due to the heightened cancer risks associated with these genetic conditions. This review explores genetic profiling impact on surgical decisions for hereditary colorectal cancer (HCRC), assessing options, timing, and outcomes. Genotypes of different HCRCs are discussed, revealing a connection between genetic profiles, disease severity, and outcomes. For Lynch syndrome, mutations in the MLH1, MSH2, MSH6, and PMS2 genes guide the choice of surgery. Subtotal colectomy is recommended for patients with mutations in MLH1 and MSH2, while segmental colectomy is preferred for those with MSH6 and PMS2 mutations. In cases of metachronous colon cancer after segmental colectomy, subtotal colectomy with ileorectal anastomosis is advised for all mutations. Surgical strategies for primary rectal cancer include anterior resection or abdominoperineal resection (APR), irrespective of the specific mutation. For rectal cancer occurring after a previous segmental colectomy, proctocolectomy with ileal pouch-anal anastomosis (IPAA) or APR with a permanent ileostomy is recommended. In FAP, surgical decisions are based on genotype-phenotype correlations. The risk of desmoid tumors post-surgery supports a single-stage approach, particularly for certain APC gene variants. Juvenile Polyposis Syndrome (JPS) surgical decisions involve genetic testing, polyp characteristics with attention to vascular lesions in SMAD4 mutation carriers. However, genetic profiling does not directly dictate the specific surgical approach for JPS. In conclusion this review highlights the critical role of personalized surgical plans based on genetic profiles to optimize patient outcomes and reduce cancer risk. Further research is needed to refine these strategies and enhance clinical guidelines.

Complications of colonoscopy surveillance of patients with Lynch syndrome - 33 years of follow up

BACKGROUND AND STUDY AIMS

Lynch syndrome (LS) is a hereditary autosomal dominant condition, with an increased lifetime risk of developing malignancies including colorectal cancer (CRC). Current guidelines differ in recommended colonoscopy-surveillance intervals from 1 to 2 years. Although colonoscopy is considered a safe procedure, there are risks of severe adverse events (SAEs), such as perforation and bleeding, as well as adverse events (AEs), such as abdominal discomfort and post-colonoscopy gastrointestinal infections. Colonoscopy-related bleeding and perforation rates have been reported 0.17% and 0.11%, respectively. However, there are insufficient data regarding complications of colonoscopy-surveillance for LS patients. This study aims to investigate the risk of AEs among LS patients during colonoscopy in the Stockholm region.

PATIENTS AND METHODS

This retrospective cohort study includes 351 LS patients undergoing endoscopic surveillance at the Karolinska University Hospital, August 1989 - April 2021. Data from endoscopic surveillance colonoscopies were extracted from patients' medical records.

RESULTS

Of 1873 endoscopies in 351 LS patients, 12 complications (AEs) were documented within 30 days (0.64%) and with a total of 3 bleedings (SAEs, 0.16%). No perforations were identified.

CONCLUSION

Colonoscopy surveillance for LS patients shows a comparatively low risk of AEs per-examination. Colonoscopy complications per-patient, including both SAEs and AEs, show a significantly higher risk. Colonoscopy complications only including SAEs, show a comparatively low risk. Understanding the lifetime risk of surveillance-related colonoscopy complications is important when designing targeted surveillance programmes.

Metachronous colorectal cancer risk according to Lynch syndrome pathogenic variant after extensive versus partial colectomy in the Netherlands: a retrospective cohort study

BACKGROUND

Extensive colectomy (subtotal or total colectomy) is often advised for carriers of Lynch syndrome with colorectal cancer. However, the risk of metachronous colorectal cancer might differ by Lynch syndrome variant, meaning that partial colectomy, which has better functional outcomes, might be adequate for some patients with low-risk variants. We aimed to assess the risk of metachronous colorectal cancer after partial colectomy and extensive colectomy in carriers of Lynch syndrome with different pathogenic variants.

METHODS

For this retrospective cohort study, carriers of Lynch syndrome with colorectal cancer in the Netherlands were identified by linkage of the Dutch Foundation for the Detection of Hereditary Tumors (StOET) database and the Dutch Nationwide Network and Registry of Histopathology and Cytopathology (PALGA) database. Data on demographics, Lynch syndrome variants, colorectal cancers, surgery types, mortality, and surveillance colonoscopies were extracted. Data on colorectal cancer and surveillance colonoscopies were updated until Feb 28, 2022. Data on survival status was updated until Feb 7, 2022. MLH1, MSH2, and EPCAM were classified as high-risk variants and MSH6 and PMS2 as low-risk variants. Patients for whom the type of surgery was unknown were excluded. Cox regression time-to-event analyses were done to assess the risk of metachronous colorectal cancer in four subgroups based on pathogenic variant (high-risk vs low-risk variants) and the extent of surgery (extensive colectomy vs partial colectomy). Sex, age at the time of primary colorectal cancer, primary colorectal cancer stage, performance of surveillance colonoscopies, adherence to the surveillance guidelines, and time period of primary colorectal cancer diagnosis were added to the model as possible confounders. Metachronous colorectal cancer was defined as colorectal cancer diagnosed more than 6 months after the primary colorectal cancer. Patients were censored at time of death or assembly of the database.

FINDINGS

Of 1908 carriers of Lynch syndrome registered in StOET, 532 with a history of colorectal cancer were identified after linkage with PALGA. Five carriers were excluded because of an unknown surgery type, leaving 527 in our sample (mean age at primary colorectal cancer 48·7 years [SD 12·1]; 274 [52%] male and 253 [48%] female). 121 (23%) patients developed metachronous colorectal cancer (median time from primary colorectal cancer to metachronous colorectal cancer 11·0 years [IQR 2·1-17·8]). Metachronous colorectal cancer occurred in 12 (12%) of 97 patients with high-risk variants and extensive colectomy, in 85 (32%) of 267 patients with high-risk variants and partial colectomy, in zero (0%) of 11 patients with low-risk variants and extensive colectomy, and in 24 (16%) of 152 patients with low-risk variants and partial colectomy. Partial colectomy was associated with a higher risk of metachronous colorectal cancer than extensive colectomy in the high-risk variant group (hazard ratio 1·97, 95% CI 1·04-3·73; p=0·039). The risk of metachronous colorectal cancer did not differ between carriers of low-risk variants who had partial colectomy and those of high-risk variants who had extensive colectomy (1·14, 0·55-2·36; p=0·72).

INTERPRETATION

The risk of metachronous colorectal cancer after partial colectomy in carriers of low-risk variants is similar to the risk after extensive colectomy in carriers of high-risk variants. This finding suggests that partial colectomy followed by endoscopic surveillance is an appropriate management approach to treat colorectal cancer in carriers of low-risk Lynch syndrome variants.

FUNDING

None.

Preventive strategies in familial and hereditary colorectal cancer

Colorectal cancer is a leading cause of cancer-related deaths worldwide. While most cases are sporadic, a significant proportion of cases are associated with familial and hereditary syndromes. Individuals with a family history of colorectal cancer have an increased risk of developing the disease, and those with hereditary syndromes such as Lynch syndrome or familial adenomatous polyposis have a significantly higher risk. In these populations, preventive strategies are critical for reducing the incidence and mortality of colorectal cancer. This review provides an overview of current preventive strategies for individuals at increased risk of colorectal cancer due to familial or hereditary factors. The manuscript includes a discussion of risk assessment and genetic testing, highlighting the importance of identifying at-risk individuals and families. This review describes various preventive measures, including surveillance colonoscopy, chemoprevention, and prophylactic surgery, and their respective benefits and limitations. Together, this work highlights the importance of preventive strategies in familial and hereditary colorectal cancer.

Delphi Initiative for Early-Onset Colorectal Cancer (DIRECt) International Management Guidelines

BACKGROUND & AIMS

Patients with early-onset colorectal cancer (eoCRC) are managed according to guidelines that are not age-specific. A multidisciplinary international group (DIRECt), composed of 69 experts, was convened to develop the first evidence-based consensus recommendations for eoCRC.

METHODS

After reviewing the published literature, a Delphi methodology was used to draft and respond to clinically relevant questions. Each statement underwent 3 rounds of voting and reached a consensus level of agreement of ≥80%.

RESULTS

The DIRECt group produced 31 statements in 7 areas of interest: diagnosis, risk factors, genetics, pathology-oncology, endoscopy, therapy, and supportive care. There was strong consensus that all individuals younger than 50 should undergo CRC risk stratification and prompt symptom assessment. All newly diagnosed eoCRC patients should receive germline genetic testing, ideally before surgery. On the basis of current evidence, endoscopic, surgical, and oncologic treatment of eoCRC should not differ from later-onset CRC, except for individuals with pathogenic or likely pathogenic germline variants. The evidence on chemotherapy is not sufficient to recommend changes to established therapeutic protocols. Fertility preservation and sexual health are important to address in eoCRC survivors. The DIRECt group highlighted areas with knowledge gaps that should be prioritized in future research efforts, including age at first screening for the general population, use of fecal immunochemical tests, chemotherapy, endoscopic therapy, and post-treatment surveillance for eoCRC patients.

CONCLUSIONS

The DIRECt group produced the first consensus recommendations on eoCRC. All statements should be considered together with the accompanying comments and literature reviews. We highlighted areas where research should be prioritized. These guidelines represent a useful tool for clinicians caring for patients with eoCRC.

PMS2-associated Lynch syndrome: Past, present and future

Carriers of any pathogenic variant in one of the MMR genes (path_MMR carriers) were traditionally thought to be at comparable risk of developing a range of different malignancies, foremost colorectal cancer (CRC) and endometrial cancer. However, it is now widely accepted that their cancer risk and cancer spectrum range notably depending on which MMR gene is affected. Moreover, there is increasing evidence that the MMR gene affected also influences the molecular pathogenesis of Lynch syndrome CRC. Although substantial progress has been made over the past decade in understanding these differences, many questions remain unanswered, especially pertaining to path_PMS2 carriers. Recent findings show that, while the cancer risk is relatively low, PMS2-deficient CRCs tend to show more aggressive behaviour and have a worse prognosis than other MMR-deficient CRCs. This, together with lower intratumoral immune infiltration, suggests that PMS2-deficient CRCs might have more in common biologically with sporadic MMR-proficient CRCs than with other MMR-deficient CRCs. These findings could have important consequences for surveillance, chemoprevention and therapeutic strategies (e.g. vaccines). In this review we discuss the current knowledge, current (clinical) challenges and knowledge gaps that should be targeted by future studies.

Lynch syndrome: from detection to treatment

Lynch syndrome (LS) is an inherited cancer predisposition syndrome associated with high lifetime risk of developing tumours, most notably colorectal and endometrial. It arises in the context of pathogenic germline variants in one of the mismatch repair genes, that are necessary to maintain genomic stability. LS remains underdiagnosed in the population despite national recommendations for empirical testing in all new colorectal and endometrial cancer cases. There are now well-established colorectal cancer surveillance programmes, but the high rate of interval cancers identified, coupled with a paucity of high-quality evidence for extra-colonic cancer surveillance, means there is still much that can be achieved in diagnosis, risk-stratification and management. The widespread adoption of preventative pharmacological measures is on the horizon and there are exciting advances in the role of immunotherapy and anti-cancer vaccines for treatment of these highly immunogenic LS-associated tumours. In this review, we explore the current landscape and future perspectives for the identification, risk stratification and optimised management of LS with a focus on the gastrointestinal system. We highlight the current guidelines on diagnosis, surveillance, prevention and treatment and link molecular disease mechanisms to clinical practice recommendations.

A case of strongly suspected Lynch syndrome with colorectal neuroendocrine carcinoma

Background

Neuroendocrine cell carcinomas (NEC) of the colon and rectum are uncommon, representing ~ 0.1% of all colorectal carcinomas. They are associated with a much worse prognosis compared to adenocarcinoma of the colon and rectum, as death occurs in approximately half of all patients within 1 year. Lynch syndrome (LS) is the most common cause of inherited colorectal cancer, accounting for 2–4% of newly diagnosed colorectal cancer cases. This case is extremely rare which was strongly suspected LS as the background, and NEC as the histological type of colorectal cancer.

Case presentation

The patient was a 44-year-old man presenting with vomiting as the main complaint. He had undergone ileocecal resection for cecal cancer at age 29. The diagnosis was obstructive descending colorectal cancer, and colonoscopy revealed tumors in the rectum and sigmoid colon in addition. Due to multiple occurrences of colorectal cancer and its prevalence in the patient’s family, LS was suspected. The operation which was a subtotal proctocolectomy was performed. Pathological analysis revealed complete curative resection and the descending colon cancer of the obstructed portion was at the most advanced pathological Stage IIIC in UICC TNM classification, and the tissue type was a NEC. The Ki-67 index was 70%. The results of the microsatellite instability (MSI) test showed high-frequency MSI. The BRAF V600E variant was negative. The immunoexpression of MLH1 was positive, MSH2 was negative, PMS2 was positive, and MSH6 was negative.

Conclusions

Extended surgery is recommended for incipient colorectal cancer in LS cases in order to reliably reduce the risk of developing metachronous colorectal cancer. The survival outcome of surgery alone on digestive tract NECs, even locoregional lesions that are completely resection, is extremely poor. It is currently unclear if digestive tract NECs develop more readily in patients with LS. The accumulation of additional cases is necessary.

Current practice of colonoscopy surveillance in patients with lynch syndrome: A multicenter retrospective cohort study in Japan

Objectives

Colonoscopy surveillance reduces the incidence of colorectal cancer through the detection and endoscopic removal of adenomas. Current guidelines recommend that patients with Lynch syndrome should have colonoscopy surveillance every 1–2 years starting at the age of 20–25. However, insufficient data are available to evaluate the quality and safety of colonoscopy surveillance for patients with Lynch syndrome nationwide in Japan.

Methods

Patients with Lynch syndrome (n = 309) from 13 institutions who underwent one or more colonoscopy procedures were enrolled in this retrospective analysis. Colonoscopy completion rate, colonoscopy‐related complication rate, proportion with an adequate colonoscopy interval, and adenoma detection rate were reviewed.

Results

The colonoscopy completion rate was 98.8% and a history of previous colorectal cancer surgery was significantly associated with a higher completion rate. All complications were associated with endoscopic treatment and the rate of bleeding needing hemostasis and perforation needing surgical repair were both 0.16% after colonoscopy with polypectomy. The adenoma detection rate at the first colonoscopy was 25%. Although there was no difference in the completion and complication rates based on differences in the colonoscopy experience of the endoscopist, the detection rate of adenomas and intramucosal cancers was significantly higher with more experienced endoscopists. The proportion of patients developing cancer was significantly higher with a >24 months than a ≤24 months interval.

Conclusion

High‐volume experienced endoscopists and appropriate surveillance intervals may minimize the risk of developing colorectal cancers in patients with Lynch syndrome.

Risk of Metachronous Colorectal Cancer in Lynch Syndrome: Who Needs an Extended Resection?

Lynch syndrome (LS) is the most common genetic condition associated with early-onset colorectal cancer. It is inherited in an autosomal dominant fashion. The increased cancer risk is due to a germline mutation in one of the mismatch repair (MMR) genes (MLH1, MSH2, MSH6, and PMS2) or the EPCAM gene. This leads to a deficient DNA mismatch repair mechanism, resulting in the accumulation of nucleotide changes and microsatellite instability, providing phenotypical evidence that MMR is not functioning normally. LS is associated with a high risk of early-onset colorectal cancer and recurrence. Thus, when undergoing surgery for primary colorectal cancer, extended resection should be discussed with the patient. This review provides an overview of current surgical risk-reducing strategies in LS-associated colorectal cancer. Surgical treatment for LS carriers with colorectal cancer needs to be highly individualized, based on patient and disease characteristics. Strategies are presented to guide decision making in pathologic MMR gene mutation carriers undergoing surgery for colorectal cancer.

Diagnosis and management of Lynch syndrome

Lynch syndrome (LS) is a dominantly inherited cancer susceptibility syndrome defined by presence of pathogenic variants in DNA mismatch repair genes MLH1, MSH2, MSH6 and PMS2, or in deletions of the EPCAM gene. Although LS is present in about 1 in 400 people in the UK, it estimated that only 5% of people with this condition are aware of the diagnosis. Therefore, testing for LS in all new diagnoses of colorectal or endometrial cancers is now recommended in the UK, and gastroenterologists can offer 'mainstreamed' genetic testing for LS to patients with cancer. Because LS results in a high lifetime risk of colorectal, endometrial, gastric, ovarian, hepatobiliary, brain and other cancers, the lifelong care of affected individuals and their families requires a coordinated multidisciplinary approach. Interventions such as high-quality 2-yearly colonoscopy, prophylactic gynaecological surgery, and aspirin are proven to prevent and facilitate early diagnosis and prevention of cancers in this population, and improve patient outcomes. Recently, an appreciation of the mechanism of carcinogenesis in LS-associated cancers has contributed to the development of novel therapeutic and diagnostic approaches, with a gene-specific approach to disease management, with potential cancer-preventing vaccines in development. An adaptive approach to surgical or oncological management of LS-related cancers may be considered, including an important role for novel checkpoint inhibitor immunotherapy in locally advanced or metastatic disease. Therefore, a personalised approach to lifelong gene-specific management for people with LS provides many opportunities for cancer prevention and treatment which we outline in this review.

Current guidelines in the surgical management of hereditary colorectal cancers

Incidence of colorectal cancer (CRC) is on rise. While approximately 70% of all CRC cases are sporadic in nature, 20%-25% have familial aggregation and only < 5% is hereditary in origin. Identification of individuals with hereditary predilection for CRC is critical, as it has an impact on their overall surgical management including surgical timing, approach & technique and determines the role of prophylactic surgery and outcome. This review highlights the concept of hereditary CRC, provides insight into its molecular basis, possibility of its application into clinical practice and emphasizes the current treatment strategies with surgical management, based on the available international guidelines.

Lynch syndrome; towards more personalized management?

Lynch syndrome is the most common inherited cause of colorectal (lifetime risk up to 70%) and endometrial cancer. The diagnosis of Lynch syndrome facilitates preventive measures aimed at reducing the incidence and mortality of cancer. Colonoscopic surveillance for colorectal cancer, aspirin, and prophylactic hysterectomy and bilateral salpo-oopherectomy for endometrial and/or ovarian cancer have demonstrated to effectively reduce cancer mortality in this population. However, the lifetime risk of each cancer in people with Lynch syndrome is gene-specific and may be modified by environmental factors. Furthermore, the benefits of surveillance strategies need to be balanced against the risk of over-diagnosis and be supported by evidence of improved outcomes from cancer diagnosis in surveillance. Therefore, people with Lynch syndrome may benefit from a personalized management approach.

Metachronous colorectal cancer have a similar microsatellite instability frequency but a lower infiltration of lymphomononuclear cells than primary lesions

BACKGROUND

An increased risk of metachronous colorectal cancer is usually associated with microsatellite instability occurring in Lynch syndrome. However, not all patients with metachronous colorectal cancer have microsatellite instability. The density of tumor-infiltrating lymphocytes is an independent predictor of outcome in patients with colorectal cancer, and a fascinating hypothesis is that they can be involved in the onset of metachronous colorectal cancer. The aim of this study was to analyze the tumor microenvironment and tumor mutation frequency in sporadic and metachronous colorectal cancer.

METHODS

The clinical and pathological records of a series of consecutive colorectal cancer patients who were operated on from 2015 to 2019 were retrieved for this retrospective study. We defined metachronous colorectal cancer as a second colorectal cancer that appeared at least 1 year after the primary one, and sporadic colorectal cancer as those that did not have a metachronous colorectal cancer. Histology for the infiltration of intratumoral lymphomononuclear cells, immunohistochemistry for MLH1, PMS2, MSH2, and MSH6, and mutational analysis of BRAF, KRAS, and NRAS were all performed. Sporadic colorectal cancer and metachronous colorectal cancer were compared. Nonparametric tests were used for small sample size comparison.

RESULTS

In the study, 238 patients were operated on for colorectal cancer at the General Surgery Unit of the Azienda Ospedaliera di Padova from 2015 to 2019. We identified 26 patients with metachronous colorectal cancer, and only 3 of them had had adjuvant therapy after the primary colorectal cancer. No difference was observed in terms of cancer stage between metachronous and sporadic colorectal cancer. Mismatch repair gene deficiencies and microsatellite instability frequency was similar in metachronous colorectal cancer and in sporadic colorectal cancer (P = .77). Likewise, the mutation frequency of BRAF and KRAs was similar in the 2 groups (P = .75 and P = .21, respectively). To the contrary, the absence of infiltration of lymphomononuclear cells within the tumor (P = .004) in patients with metachronous colorectal cancer was more frequent and they tended to have a higher frequency of NRAS mutation (P = .06).

CONCLUSION

Our study showed that, rather unexpectedly, microsatellite instability frequency was similar in metachronous and sporadic colorectal cancer. Moreover, our data suggest that an altered immune microenvironment may be a crucial factor, permitting the occurrence of metachronous colorectal cancer. In fact, the absence of lymphomononuclear cells can be the substrate for a weak immune response to cancer neoantigens, opening the way to a second primary colorectal cancer.

Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines 2020 for the Clinical Practice of Hereditary Colorectal Cancer

Hereditary colorectal cancer (HCRC) accounts for < 5% of all colorectal cancer cases. Some of the unique characteristics commonly encountered in HCRC cases include early age of onset, synchronous/metachronous cancer occurrence, and multiple cancers in other organs. These characteristics necessitate different management approaches, including diagnosis, treatment or surveillance, from sporadic colorectal cancer management. There are two representative HCRC, named familial adenomatous polyposis and Lynch syndrome. Other than these two HCRC syndromes, related disorders have also been reported. Several guidelines for hereditary disorders have already been published worldwide. In Japan, the first guideline for HCRC was prepared by the Japanese Society for Cancer of the Colon and Rectum (JSCCR), published in 2012 and revised in 2016. This revised version of the guideline was immediately translated into English and published in 2017. Since then, several new findings and novel disease concepts related to HCRC have been discovered. The currently diagnosed HCRC rate in daily clinical practice is relatively low; however, this is predicted to increase in the era of cancer genomic medicine, with the advancement of cancer multi-gene panel testing or whole genome testing, among others. Under these circumstances, the JSCCR guidelines 2020 for HCRC were prepared by consensus among members of the JSCCR HCRC Guideline Committee, based on a careful review of the evidence retrieved from literature searches, and considering the medical health insurance system and actual clinical practice settings in Japan. Herein, we present the English version of the JSCCR guidelines 2020 for HCRC.

European guidelines from the EHTG and ESCP for Lynch syndrome: an updated third edition of the Mallorca guidelines based on gene and gender

BACKGROUND

Lynch syndrome is the most common genetic predisposition for hereditary cancer but remains underdiagnosed. Large prospective observational studies have recently increased understanding of the effectiveness of colonoscopic surveillance and the heterogeneity of cancer risk between genotypes. The need for gene- and gender-specific guidelines has been acknowledged.

METHODS

The European Hereditary Tumour Group (EHTG) and European Society of Coloproctology (ESCP) developed a multidisciplinary working group consisting of surgeons, clinical and molecular geneticists, pathologists, epidemiologists, gastroenterologists, and patient representation to conduct a graded evidence review. The previous Mallorca guideline format was used to revise the clinical guidance. Consensus for the guidance statements was acquired by three Delphi voting rounds.

RESULTS

Recommendations for clinical and molecular identification of Lynch syndrome, surgical and endoscopic management of Lynch syndrome-associated colorectal cancer, and preventive measures for cancer were produced. The emphasis was on surgical and gastroenterological aspects of the cancer spectrum. Manchester consensus guidelines for gynaecological management were endorsed. Executive and layperson summaries were provided.

CONCLUSION

The recommendations from the EHTG and ESCP for identification of patients with Lynch syndrome, colorectal surveillance, surgical management of colorectal cancer, lifestyle and chemoprevention in Lynch syndrome that reached a consensus (at least 80 per cent) are presented.

Quadruple gastrointestinal cancer with discordance of mismatch repair protein deficiency and microsatellite instability suggesting Lynch syndrome

A 65-year-old woman with prior personal and family histories of cancer was admitted to our hospital for quadruple cancer. Preoperative endoscopy revealed a type 0-II gastric cancer (GC; gastric body), advanced type-II colon cancer (ascending colon), and early-stage recto-sigmoid colon cancers. We diagnosed her with Lynch syndrome (LS) per Amsterdam criteria, and performed distal gastrectomy, ileocecal resection and high anterior resection. Her pathological diagnoses were GC: well-to-poorly differentiated adenocarcinoma (AD, por2 > tub2) with signet-ring cells, ypT1b SM2; ascending colon cancer: AD with focal mucin products (tub2 > muc), SS; sigmoid colon cancer: AD (tub1), M; recto-sigmoid cancer: AD (tub1 > tub2), SM. Immunohistochemical tests revealed that all cancers lacked the MLH1/PMS2 protein. However, the three colon cancers were found to have high microsatellite instability (MSI); the GC was microsatellite stable (MSS). No recurrence or other cancers were observed for 30 months after surgery without adjuvant chemotherapy. As patients with LS may also develop MSS cancers, we should check for MSI in all LS cancers for proper treatment.

DNA Mismatch Repair-Deficient Colorectal Carcinoma: Referral Rate for Genetic Cancer Risk Assessment in a Brazilian Cancer Center

BACKGROUND

Approximately 15% of colorectal cancers (CRCs) are deficient in DNA mismatch repair proteins (dMMR), a characteristic that can occur in both sporadic and hereditary CRC. Due to sparse studies on dMMR CRC in the Brazilian population, we conducted a retrospective analysis of referral rates for Genetic Cancer Risk Assessment of this population and also describing clinical and molecular characterization of these tumors.

METHODS

A retrospective, longitudinal, and unicenter study that included patients with dMMR CRC detected by IHC analysis from Pathology Database of our institution, from January 2015 to July 2017.

RESULTS

MMR IHC testing was performed in 998 CRC tumors, and 78 tumors (7.8%) had dMMR. The mean age at diagnosis was 56.8 years (17-90), and most patients were female (41 out of 78, 52.6%). Of the 52 patients with right-sided CRC, 40 tumors (77%) had loss of the MLH1 and/or PMS2 expression, and 12 tumors (23%) had loss of MSH2 and/or MSH6 expression (p = 0.005). From 78 patients with dMMR CRC, only 43 patients (55.1%) were referred for genetic counseling (GC), and of them, only 33 patients (76.7%) really went to GC consultation. A total of 21 patients with dMMR CRC performed genetic testing.

CONCLUSION

Overall, genetic referral was less than expected in our population. Most of dMMR CRC patients did not receive GC, even in a cancer center, either due to the absence of referral or personal decision and few patients who pursued genetic counseling performed genetic testing.

Lynch syndrome-associated colorectal cancer in a 16-year-old girl due to a de novo MSH2 mutation

The diagnosis of paediatric colorectal cancer is an unusual finding often diagnosed at an advanced stage with associated poor survival. Paediatric colorectal cancer warrants investigation for hereditary cancer predisposition syndromes, including Lynch syndrome. Here we describe a 16-year-old girl who presented with a stage IIA mucinous adenocarcinoma of the descending colon (T3 N0 M0) treated by resection alone that was associated with a pathogenic germline mutation of MSH2 (c.1786_1788delAAT (p.Asn596del)). This previously described mutation was not found in either parent or her three siblings. To our knowledge, this is the earliest reported case of paediatric Lynch syndrome-associated colorectal cancer by de novo mutation of MSH2 This case illustrates that although Lynch syndrome is typically described as an adult-onset cancer syndrome, Lynch syndrome-associated colorectal cancer can be found in children and adolescents. Genetic testing should be considered as a part of the initial evaluation in these patients.

Adequacy evaluation of the annual colonoscopic surveillance and individual difference of disease phenotypes in Lynch syndrome

BACKGROUND

Regular endoscopic surveillance for Lynch syndrome is reported to reduce colorectal cancer (CRC)-related mortality. However, the appropriate surveillance intervals are still unclear. We evaluated the adequacy of annual colonoscopy and investigated the differences in tumor occurrence rates between individual patients.

METHODS

In total, 25 patients with Lynch syndrome who underwent colonoscopic surveillance between 2007 and 2016 at the Iwakuni Clinical Center were included. We retrospectively investigated the surveillance frequency and the clinical features associated with tumor development.

RESULTS

Colonoscopic surveillance was performed every 397 days on average. A total of 101 tumors, including 8 intramucosal carcinomas and 15 carcinomas, were observed within the study period. Annual colonoscopy detected six malignancies, including a carcinoma requiring surgery. Tumor incidence was associated with tumor existence in the initial colonoscopies (P = 0.018). Patients with a tumor occurrence rate of 0.4 tumors per year during our observation period were significantly more likely to have malignancies detected during regular surveillance than patients who had a lower occurrence rate (P < 0.001). Malignancy occurrence rate was strongly associated with tumor occurrence rate (P < 0.001, R2 = 0.44).

CONCLUSIONS

Annual colonoscopic surveillance for Lynch syndrome patients was effective in reducing the risk of CRC progression, but was insufficient to completely avoid surgery. Because the tumor occurrence rate differed substantially between individuals, more intensive surveillance was required for high-risk patients.

Risk factors for metachronous colorectal cancer in Lynch syndrome patients: a registry-based observational mono-institutional study cohort

BACKGROUND

Risk factors for metachronous colorectal cancer (mCRC) in Lynch Syndrome (LS) patients are essential for colorectal cancer (CRC) treatment strategy to perform not only a curative but also preventive surgery. The aim of this study was to evaluate the risk factors for mCRC development in LS patients to define the patient subset that may benefit an extended curative and preventive surgical resection.

METHODS

Patient's clinical history, oncological, molecular and follow-up were collected retrospectively from the Hereditary Digestive Tumors Registry at the National Cancer Institute of Milan. The age-related cumulative risk of mCRC was calculated using the Kaplan-Meier method. Factors significantly associated with mCRC were analyzed with a Cox regression model. Overall and specific competitive risks were also calculated.

RESULTS

In a total of 1346 CRC patients, 159 (11.8%) developed a mCRC after a mean follow-up of 138 months from the primary tumor. The independent risk factors reported by a multivariate analysis were: pathogenetic variants in MLH1 and MSH2 (HR 2.96 and 1.91, respectively) and history of colorectal adenomas (HR 1.54); whereas female sex and extended surgery were protective (HR 0.59 and 0.79, respectively).

CONCLUSIONS

Among a high-risk population for CRC, in particular LS, an extended surgery may be considered in CRC patients with specific risk factors (MLH1 or MSH2 germline pathogenic variants, history of colorectal adenomas) to reduce the risk of mCRC development.

Guidelines for the management of hereditary colorectal cancer from the British Society of Gastroenterology (BSG)/Association of Coloproctology of Great Britain and Ireland (ACPGBI)/United Kingdom Cancer Genetics Group (UKCGG)

Heritable factors account for approximately 35% of colorectal cancer (CRC) risk, and almost 30% of the population in the UK have a family history of CRC. The quantification of an individual's lifetime risk of gastrointestinal cancer may incorporate clinical and molecular data, and depends on accurate phenotypic assessment and genetic diagnosis. In turn this may facilitate targeted risk-reducing interventions, including endoscopic surveillance, preventative surgery and chemoprophylaxis, which provide opportunities for cancer prevention. This guideline is an update from the 2010 British Society of Gastroenterology/Association of Coloproctology of Great Britain and Ireland (BSG/ACPGBI) guidelines for colorectal screening and surveillance in moderate and high-risk groups; however, this guideline is concerned specifically with people who have increased lifetime risk of CRC due to hereditary factors, including those with Lynch syndrome, polyposis or a family history of CRC. On this occasion we invited the UK Cancer Genetics Group (UKCGG), a subgroup within the British Society of Genetic Medicine (BSGM), as a partner to BSG and ACPGBI in the multidisciplinary guideline development process. We also invited external review through the Delphi process by members of the public as well as the steering committees of the European Hereditary Tumour Group (EHTG) and the European Society of Gastrointestinal Endoscopy (ESGE). A systematic review of 10 189 publications was undertaken to develop 67 evidence and expert opinion-based recommendations for the management of hereditary CRC risk. Ten research recommendations are also prioritised to inform clinical management of people at hereditary CRC risk.

A dedicated high-quality service for the management of patients with an inherited risk of colorectal cancer

AIM

To demonstrate the quality improvement associated with the implementation of a specialist family history of bowel cancer service in secondary care.

METHOD

The following outcomes were assessed: (1) adherence to the British Society of Gastroenterology (BSG) guidelines for colonoscopic surveillance of individuals with a family history of colorectal cancer (CRC); (2) adherence to the revised Bethesda criteria for the identification of CRC patients with suspected Lynch syndrome; (3) identification of inherited syndromes with increased CRC risk; and (4) colonoscopic adenoma detection rate. Data were collected for a 21-month period before and after the establishment of this service for all patients who underwent colonoscopic surveillance for a family history of CRC and all patients newly diagnosed with CRC. Analyses compared the number of colonoscopies performed that were not indicated by BSG guidelines, the average number of years early that patients were screened, the adenoma detection rate and the rate of tumour testing for mismatch repair genes before and after the implementation of the service.

RESULTS

Following the establishment of the service there was a reduction in the number of colonoscopies not indicated by BSG guidelines (39.6% before and 5.8% after, P < 0.001, chi-square test) and surveillance colonoscopy took place at a more appropriate age (10.6 years too early before and 5.9 years early after, P = 0.01, t-test). There was an increased adenoma detection rate (17% before and 31.9% after, P < 0.01, chi-square test) and increased tumour MMR testing (3.4% before and 91.8% after, P < 0.01, chi-square test).

CONCLUSION

The introduction of a family history of bowel cancer service results in improved patient care through improved adherence to guidelines for colonoscopic surveillance and increased cancer detection rates.

Management of genetically determined colorectal cancer

Surgeons are increasingly treating patients for colorectal cancer who are known to have a genetic predisposition to develop the disease; this may modify the surgical and oncological management of the patient. In this review the approach to the patient with colorectal cancer on a background of Lynch syndrome or familial adenomatous polyposis is explored.