Risk of colonic neoplasia after proctectomy for rectal cancer in hereditary nonpolyposis colorectal cancer

Lynch Syndrome-Impact of the Type of Deficient Mismatch Repair Gene Mutation on Diagnosis, Clinical Presentation, Surveillance and Therapeutic Approaches

In today's world, with its continuing advancements in genetics, the identification of Lynch syndrome (LS) increasingly relies on sophisticated genetic testing techniques. Most guidelines recommend a tailored surveillance program, as well as personalized prophylactic and therapeutic approaches, according to the type of dMMR gene mutation. Carriers of path_MLH1 and path_MSH2 genes have a higher risk of developing colorectal cancer (CRC), despite intensive colonoscopic surveillance. Conversely, carriers of path_MSH6 and path_PMS2 genes have a lower risk of developing CRC, which may be due to their lower penetrance and later age of onset. Thus, carriers of path_MLH1 or path_MSH2 would theoretically derive greater benefits from total colectomy, compared to low-risk carriers (path_MSH6 and path_PMS2), in which colonoscopic surveillance might achieve an efficient prophylaxis. Furthermore, regarding the risk of endometrial/ovarian cancer development, there is a global agreement to offer both hysterectomy and bilateral salpingo-oophorectomy to path_MLH1, path_MSH2 and path_MSH6 carriers after the age of 40. In patients with CRC, preoperative knowledge of the diagnosis of LS is of tremendous importance, due to the high risk of metachronous CRC. However, this risk depends on the type of dMMR gene mutation. For carriers of the high-risk variants (MLH1, MSH2 and EPCAM) who have already developed colon cancer, it is strongly recommended a subtotal or total colectomy is performed, while partial colectomy followed by endoscopic surveillance is an appropriate management approach to treat colon cancer in carriers of the low-risk variants (MSH6 and PMS2). On the other hand, extended surgery for index rectal cancer (such as total proctocolectomy) is less effective than extended surgery for index colon cancer from the point of view of metachronous CRC risk reduction, and is associated with a decreased quality of life.

Risk of metachronous colorectal cancer after surgical resection of index rectal cancer in Lynch syndrome: a multicenter retrospective study in Japan

PURPOSE

This study evaluated the risk of metachronous colorectal cancer (CRC) after resection of index (first) rectal cancer in patients with Lynch syndrome (LS).

METHODS

Clinicopathological data of patients with genetically proven LS were retrospectively analyzed in this multicenter Japanese study. The cumulative incidence of metachronous CRC and the overall survival were compared between patients with index rectal cancer (rectal group) and those with index colon cancer (colon group).

RESULTS

The median age at index CRC surgery was lower in the rectal group than in the colon group (37 vs. 46 years old, P = 0.01). The cumulative 5-, 10-, and 20-year incidences of metachronous CRC were 3.5%, 13.9%, and 21.1%, respectively, in the rectal cancer group and 14.9%, 22.0%, and 57.9%, respectively, in the colon cancer group (P = 0.02). The overall survival curves were not significantly different between two groups (P = 0.23).

CONCLUSION

This is the first report from an East Asian country to report the risk of metachronous CRC after resection of index rectal cancer in patients with LS. Despite this study having several limitations, we cannot recommend extended resection, such as total proctocolectomy, for index rectal cancer as a standard surgical treatment in patients with LS.

Treatment of Microsatellite-Unstable Rectal Cancer in Sporadic and Hereditary Settings

Microsatellite instability is rare in rectal cancer and associated with younger age of onset and Lynch syndrome. All rectal cancers should be tested for microsatellite instability prior to treatment decisions. Patients with microsatellite instability are relatively resistant to chemotherapy. However, recent small studies have shown dramatic response with neoadjuvant immunotherapy. Patients with Lynch syndrome have a hereditary predisposition to cancer and thus an elevated risk of metachronous cancer. Therefore, while "watch and wait" is a well-established practice for sporadic rectal cancers that obtain a complete clinical response after chemoradiation, its safety in patients with Lynch syndrome has not yet been defined. The extent of surgery for patients with Lynch syndrome and rectal cancer is controversial and there is significant debate as to the relative advantages of a segmental proctectomy with postoperative endoscopic surveillance versus a therapeutic and prophylactic total proctocolectomy. Surgical decision making for the patient with Lynch syndrome and rectal cancer is complex and demands a multidisciplinary approach, taking into account both patient- and tumor-specific factors. Neoadjuvant immunotherapy show great promise in the treatment of these patients, and further maturation of data from prospective trials will likely change the current treatment paradigm. Patients with Lynch syndrome and rectal cancer who do not undergo total proctocolectomy require yearly surveillance colonoscopies and should consider chemoprophylaxis with aspirin.

Management of Rectal Cancer in Lynch Syndrome: Balancing Risk Reduction and Quality of Life

Patients with Lynch syndrome are predisposed to developing colorectal cancer and a variety of extracolonic malignancies, at a young age. The management of rectal cancer in the setting of Lynch syndrome is a complex clinical scenario that requires the expertise of a multidisciplinary management team. In this review, we delve into the approach for rectal cancer in these patients, and specifically focus on several key aspects of treatment. Some unique aspects of rectal cancer in Lynch syndrome include the decision between proctectomy alone versus total proctocolectomy with or without an ileal pouch, the utility of chemotherapy and immunotherapy, nonoperative rectal cancer management, and the management of rectal polyps. Throughout, we highlight the delicate interplay between future cancer risk reduction and quality of life optimization.

Overexpression of SYNGAP1 suppresses the proliferation of rectal adenocarcinoma via Wnt/β-Catenin signaling pathway

Rectal adenocarcinoma (READ) is a common malignant tumor of the digestive tract. Growing studies have confirmed Ras GTPase-activating proteins are involved in the progression of several tumors. This study aimed to explore the expression and function of Ras GTPase-activating proteins in READ. In this study, we analyzed RNA sequencing data from 165 patients with READ and 789 normal tissue samples, identifying 5603 differentially expressed genes (DEGs), including 2937 upregulated genes and 2666 downregulated genes. Moreover, we also identified two dysregulated genes, RASA4 and SYNGAP1, among six Ras GTPase-activating proteins. High NF1 expression was associated with longer overall survival, while high SYNGAP1 expression showed a trend towards extended overall survival. Further analysis revealed the mutation frequency and copy number variations of Ras GTPase-activating proteins in various cancer samples. Additionally, DNA methylation analysis demonstrated a negative correlation between DNA methylation of Ras GTPase-activating proteins and their expression. Moreover, among Ras GTPase-activating proteins, we focused on SYNGAP1, and experimental validation confirmed that the overexpression of SYNGAP1 in READ significantly suppressed READ cell proliferation and increased apoptosis via regulating the Wnt/β-Catenin signaling pathway. These findings underscored the potential significance of SYNGAP1 in READ and provide new insights for further research and treatment.

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.

Ability of a polygenic risk score to refine colorectal cancer risk in Lynch syndrome

BACKGROUND

Polygenic risk scores (PRSs) have been used to stratify colorectal cancer (CRC) risk in the general population, whereas its role in Lynch syndrome (LS), the most common type of hereditary CRC, is still conflicting. We aimed to assess the ability of PRS to refine CRC risk prediction in European-descendant individuals with LS.

METHODS

1465 individuals with LS (557 MLH1, 517 MSH2/EPCAM, 299 MSH6 and 92 PMS2) and 5656 CRC-free population-based controls from two independent cohorts were included. A 91-SNP PRS was applied. A Cox proportional hazard regression model with 'family' as a random effect and a logistic regression analysis, followed by a meta-analysis combining both cohorts were conducted.

RESULTS

Overall, we did not observe a statistically significant association between PRS and CRC risk in the entire cohort. Nevertheless, PRS was significantly associated with a slightly increased risk of CRC or advanced adenoma (AA), in those with CRC diagnosed <50 years and in individuals with multiple CRCs or AAs diagnosed <60 years.

CONCLUSION

The PRS may slightly influence CRC risk in individuals with LS in particular in more extreme phenotypes such as early-onset disease. However, the study design and recruitment strategy strongly influence the results of PRS studies. A separate analysis by genes and its combination with other genetic and non-genetic risk factors will help refine its role as a risk modifier in LS.

[Surgical strategies for hereditary colorectal cancer]

Hereditary colorectal cancer (hCRC) represents a major diagnostic and therapeutic challenge. In addition to the usual diagnostic methods, the family history, histological confirmation and mutation analysis play an important role in identifying the type of hereditary CRC. The diagnosis and classification of hCRC are carried out based on the anamnesis, clinical presentation and histology and the further treatment is determined depending on the underlying type of hCRC. For familial adenomatous polyposis (FAP) coloproctomucosectomy after the end of puberty is always recommended, whereas the treatment recommendations for other forms, such as attenuated FAP (aFAP), MUTYH-associated polyposis (MAP) and hereditary nonpolyposis colon cancer (HNPCC, Lynch syndrome), range from close surveillance and endoscopic control, through segmental resection up to colectomy. Irrespective of the type of hCRC, the treatment regimens necessitate an individualized approach and require close interdisciplinary cooperation. When colorectal resection is performed, minimally invasive procedures should principally be prioritized and some studies could demonstrate a potential benefit of robotic surgery compared to laparoscopy.

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.

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.

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.

Delivery of Personalized Care for Locally Advanced Rectal Cancer: Incorporating Pathological, Molecular Genetic, and Immunological Biomarkers Into the Multimodal Paradigm

Approximately one-third of all newly diagnosed colorectal cancer (CRC) is composed of rectal cancer, with the incidence rising in younger patients. The principal neoadjuvant treatments consist of neoadjuvant short-course radiotherapy and long-course chemoradiation. Locally advanced rectal cancer (LARC) is particularly challenging to manage given the anatomical constrictions of the pelvis and the risk for local recurrence. In appropriately treated patients, 5- and 10-year overall survival is estimated at 60 and 50%, respectively. The prognosis for LARC has improved in recent years with more access to screening, advances in surgical techniques, and perioperative care. Furthermore, the refinement of the multidisciplinary team with combined-modality management strategies has improved outcomes. These advancements have been augmented by significant improvements in the understanding of the underlying tumor biology. However, there are many instances where patient outcomes do not match those for their tumor stage and accurate prognostic information for individual patients can be difficult to estimate owing to the heterogeneous nature of LARC. Many new combinations of chemotherapy with radiotherapy, including total neoadjuvant therapy with targeted therapies that aim to diminish toxicity and increase survival, are being evaluated in clinical trials. Despite these advances, local recurrence and distant metastasis remain an issue, with one-third of LARC patients dying within 5 years of initial treatment. Although much of the new pathological, molecular genetics, and immunological biomarkers allow refinement in the classification and prognostication of CRC, the relative importance of each of these factors with regards to the development and progression of LARC remains incompletely understood. These factors are often insufficiently validated and seldom consider the individual characteristics of the host, the tumor and its location, the local available expertise, or the probable location of recurrence. Appreciating the mechanisms behind these differences will allow for a more comprehensive, personalized approach and more informed treatment options, leading to ultimately superior outcomes. This review aims to first outline the current multidisciplinary context in which LARC care should be delivered and then discuss how some key prognosticators, including novel histopathological, molecular genetics, and immunological biomarkers, might fit into the wider context of personalized LARC management in the coming years.

Analysis of metachronous colorectal neoplasms and survival following segmental or extended resection in patients with hereditary non-polyposis colorectal cancer

PURPOSE

The high incidence of metachronous colorectal tumours in patients with hereditary non-polyposis colorectal cancer (HNPCC) encourages extended resection (ER); however, the optimal surgical approach remains unclear. We evaluated the incidences of metachronous colorectal neoplasms following curative colorectal cancer segmental resection (SR) vs ER in patients with HNPCC and investigated patients' oncologic outcomes according to surgical modality and mismatch repair status.

METHODS

We retrospectively investigated medical records of patients with HNPCC (per the Amsterdam II criteria) treated for primary colon cancer at our institution between 2001 and 2017. All patients underwent intensive endoscopic surveillance.

RESULTS

We included 87 patients (36 who underwent SR and 51 who underwent ER). The cumulative incidence of metachronous adenoma was higher in the SR group. One patient in the SR group (2.8%) and 3 in the ER group (5.9%) developed metachronous colon cancer; the difference was not significant (P = 0.693). Four patients in the SR group (11.1%) and 1 in the ER group (2.0%) developed distant recurrences; again, the difference was not significant (P = 0.155). Moreover, no significant differences were observed in the 5-year overall survival rates of patients in the SR and ER groups (88.2% vs 95.5%, P = 0.446); the same was true for 5-year disease-free survival rates (79.5% vs 91.0%, P = 0.147).

CONCLUSION

The incidence of metachronous cancer was not significantly different between the ER and SR groups; however, that of cumulative metachronous adenoma was higher in the SR group. Hence, intensive surveillance colonoscopy may be sufficient for patients with HNPCC after non-extensive colon resection.

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.

Prophylactic Surgery and Extended Oncologic Radicality in Gastric and Colorectal Hereditary Cancer Syndromes

Prophylactic surgery for high-penetrance hereditary gastric and colorectal cancer can be a primary prophylaxis of cancer and a secondary oncologic prevention. As early cancer is often detected in the resected organ, there has been no prophylaxis of cancer but cancer treatment. Extended oncological radicality with removal of the complete organ is a tertiary prevention as metachronous cancer is avoided. The indication for prophylactic surgery or extended oncological radicality is presented regarding hereditary and familial gastric and colorectal cancer. Hereditary diffuse type gastric cancer (E-cadherin mutation) and familial adenomatous polyposis coli (APC or MYH mutation) are well-accepted indications for prophylactic surgery with a variety of considerations regarding phenotype, genotype, associated diseases, age, timing, extent, and technique of surgery. Not so much prophylactic surgery as extended oncologic radicality can be considered in familial gastric and colorectal cancer as well as Lynch or hereditary nonpolyposis colorectal cancer syndrome (HNPCC). Clinical, molecular, and technical progress leads to less invasive and risk-adapted surgical and nonsurgical interventions, expanding the variety of individualized treatment options.

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.

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

Around 5% of colorectal cancers are due to mutations within DNA mismatch repair genes, resulting in Lynch syndrome (LS). These mutations have a high penetrance with early onset of colorectal cancer at a mean age of 45 years. The mainstay of surgical management is either a segmental or extensive colectomy. Currently there is no unified agreement as to which management strategy is superior due to limited conclusive empirical evidence available. A systematic review and meta- analysis to evaluate the risk of metachronous colorectal cancer (MCC) and mortality in LS following segmental and extensive colectomy. A systematic review of the PubMed database was conducted. Studies were included/ excluded based on pre-specified criteria. To assess the risk of MCC and mortality attributed to segmental or extensive colectomies, relative risks (RR) were calculated and corresponding 95% confidence intervals (CI). Publication bias was investigated using funnel plots. Data about mortality, as well as patient ascertainment [Amsterdam criteria (AC), germline mutation (GM)] were also extracted. Statistical analysis was conducted using the R program (version 3.2.3). The literature search identified 85 studies. After further analysis ten studies were eligible for inclusion in data synthesis. Pooled data identified 1389 patients followed up for a mean of 100.7 months with a mean age of onset of 45.5 years of age. A total 1119 patients underwent segmental colectomies with an absolute risk of MCC in this group of 22.4% at the end of follow-up. The 270 patients who had extensive colectomies had a MCC absolute risk of 4.7% (0% in those with a panproctocolecomy). Segmental colectomy was significantly associated with an increased relative risk of MCC (RR = 5.12; 95% CI 2.88-9.11; Fig. 1), although no significant association with mortality was identified (RR = 1.65; 95% CI 0.90-3.02). There was no statistically significant difference in the risk of MCC between AC and GM cohorts (p = 0.5, Chi-squared test). In LS, segmental colectomy results in a significant increased risk of developing MCC. Despite the choice of segmental or extensive colectomies having no statistically significant impact on mortality, the choice of initial surgical management can impact a patient's requirement for further surgery. An extensive colectomy can result in decreased need for further surgery; reduced hospital stays and associated costs. The significant difference in the risk of MCC, following segmental or extensive colectomies should be discussed with patients when deciding appropriate management. An individualised approach should be utilised, taking into account the patient's age, co-morbidities and genotype. In order to determine likely germline-specific effects, or a difference in survival, larger and more comprehensive studies are required.

Colorectal polyposis and inherited colorectal cancer syndromes

The majority of colorectal cancer (CRC) cases are sporadic, with hereditary factors contributing to approximately 35% of CRC cases. Less than 5% of CRC is associated with a known genetic syndrome. Although adenomatous polyposis syndromes, hamartomatous polyposis syndromes, and those previously classified as non-polyposis CRC syndromes are quite rare, it is important for clinicians to know the characteristics of each syndrome and to understand the differences in cancer risks between the different conditions. This information is very important when treatment and surveillance plans are formulated for each individual patient.

Feasibility of Segmental Colectomy Followed by Endoscopic Surveillance as a Treatment Strategy for Colorectal Cancer Patients with Lynch Syndrome

BACKGROUND

Initial surgical procedures for colorectal cancer (CRC) patients with Lynch syndrome remain controversial. This study assessed the validity of segmental colectomy (SGC) followed by endoscopic surveillance as a treatment strategy for CRC patients with Lynch syndrome.

METHODS

Among consecutive patients who underwent surgery for primary CRC between April 1985 and December 2014, 49 patients were observed to have germline mutations in a mismatch repair gene, and 38 patients who underwent SGC followed by periodic endoscopic surveillance at our institution were evaluated for metachronous CRC, need for secondary surgery, and the details of endoscopic surveillance.

RESULTS

Of the 38 patients who underwent SGC followed by periodic endoscopic surveillance at our institution, 6 (15.8%) patients showed metachronous CRC, 3 (7.9%) patients underwent endoscopic resection, and the other 3 patients (7.9%) underwent secondary surgery. The dispersion of the endoscopic surveillance interval was significantly greater in patients with metachronous CRC (364 ± 332.9 days) than in those without metachronous CRC (370 ± 129.7 days; p < 0.001).

CONCLUSIONS

SGC followed by annual endoscopic surveillance was feasible as a treatment strategy for CRC patients with Lynch syndrome, because the incidence of metachronous CRC and the need for secondary surgery were low. Annual and periodic endoscopic surveillance might be essential for early detection of metachronous CRC and prevention of secondary surgery because of metachronous CRC in CRC patients with Lynch syndrome after SGC.

The current value of determining the mismatch repair status of colorectal cancer: A rationale for routine testing

Colorectal Cancer (CRC) is the third most prevalent cancer in men and women. Up to 15% of CRCs display microsatellite instability (MSI). MSI is reflective of a deficient mismatch repair (MMR) system and is most commonly caused by hypermethylation of the MLH1 promoter. However, it may also be due to autosomal dominant constitutional mutations in DNA MMR, termed Lynch Syndrome. MSI may be diagnosed via polymerase chain reaction (PCR) or alternatively, immunohistochemistry (IHC) can identify MMR deficiency (dMMR). Many institutions now advocate universal tumor screening of CRC via either PCR for MSI or IHC for dMMR to guide Lynch Syndrome testing. The association of sporadic MSI with methylation of the MLH1 promoter and an activating BRAF mutation may offer further exclusion criteria for genetic testing. Aside from screening for Lynch syndrome, MMR testing is important because of its prognostic and therapeutic implications. Several studies have shown MSI CRCs exhibit different clinicopathological features and prognosis compared to microsatellite-stable (MSS) CRCs. For example, response to conventional chemotherapy has been reported to be less in MSI tumours. More recently, MSI tumours have been shown to be responsive to immune-checkpoint inhibition providing a novel therapeutic strategy. This provides a rationale for routine testing for MSI or dMMR in CRC.

DNA Mismatch Repair Deficiency in Rectal Cancer: Benchmarking Its Impact on Prognosis, Neoadjuvant Response Prediction, and Clinical Cancer Genetics

PURPOSE

DNA mismatch repair deficiency (dMMR) hallmarks consensus molecular subtype 1 of colorectal cancer. It is being routinely tested, but little is known about dMMR rectal cancers. The efficacy of novel treatment strategies cannot be established without benchmarking the outcomes of dMMR rectal cancer with current therapy. We aimed to delineate the impact of dMMR on prognosis, the predicted response to fluoropyrimidine-based neoadjuvant therapy, and implications of germline alterations in the MMR genes in rectal cancer.

METHODS

Between 1992 and 2012, 62 patients with dMMR rectal cancers underwent multimodality therapy. Oncologic treatment and outcomes as well as clinical genetics work-up were examined. Overall and rectal cancer-specific survival were calculated by the Kaplan-Meier method.

RESULTS

The median age at diagnosis was 41 years. MMR deficiency was most commonly due to alterations in MSH2 (53%) or MSH6 (23%). After a median follow-up of 6.8 years, the 5-year rectal cancer-specific survival was 100% for stage I and II, 85.1% for stage III, and 60.0% for stage IV disease. Fluoropyrimidine-based neoadjuvant chemoradiation was associated with a complete pathologic response rate of 27.6%. The extent of surgical resection was influenced by synchronous colonic disease at presentation, tumor height, clinical stage, and pelvic radiation. An informed decision for a limited resection focusing on proctectomy did not compromise overall survival. Five of the 11 (45.5%) deaths during follow-up were due to extracolorectal malignancies.

CONCLUSION

dMMR rectal cancer had excellent prognosis and pathologic response with current multimodality therapy including an individualized surgical treatment plan. Identification of a dMMR rectal cancer should trigger germline testing, followed by lifelong surveillance for both colorectal and extracolorectal malignancies. We herein provide genotype-specific outcome benchmarks for comparison with novel interventions.

Total colectomy for multiple metachronous colon cancers in a patient with Lynch syndrome

Lynch syndrome (LS) is a disorder caused by mismatch repair gene mutations, which have been recognized to be associated with an increased frequency of colorectal and extracolorectal tumors. However, it remains controversial as to whether total or segmental colectomy should be performed to treat colorectal cancer in patients with LS. A 58-year-old male underwent total colectomy with ileostomy for advanced transverse colon cancer. He was also found to have LS based on his characteristic family history and the findings of a preoperative examination, including a microsatellite instability analysis of past multiple metachronous cancers. The postoperative histological findings showed mucinous adenocarcinoma without lymph node metastasis, and the loss of the MSH2 protein expression was confirmed on an immunohistochemical examination. The present case provided important information on the clinical management of multiple developing metachronous colorectal cancers in patients with LS.

Managing young colorectal cancer: a UK and Irish perspective

OBJECTIVE

Young patients with familial syndromes have an increased metachronous cancer rate. Effective management is possible by identifying this high-risk group prior to index colectomy. The study surveys the Association of Coloproctology of Great Britain and Ireland (ACPGBI) membership preoperative evaluation and clinical management in young patients with colorectal cancer (CRC).

METHOD

An electronic survey was sent to the membership of the ACPGBI. The survey polled members on clinical scenarios relating to young-onset CRC patients. We were particularly concerned with preoperative management strategies, the extent of colectomy, and postoperative surveillance. Survey responses were collated and analysed.

RESULTS

A total of 124 members responded to the survey and 74 completed the survey. Of these, 87.8 % would proceed to colectomy without preoperative tumor or genetic testing. Decisions regarding the extent of colectomy depended on family history. A total of 67 (90.6 %) would offer a limited colectomy with no family history, 49 (66.2 %) in a patient with familial CRC type X, 29 (39.2 %) in a young patient with Lynch syndrome. A similar trend was seen with young rectal cancer. Only 16 surgeons (21.6 %) could identify a syndrome of MYH-associated polyposis (MAP).

CONCLUSION

The majority of ACPGBI members will not offer preoperative risk testing based on a young age alone; however, the majority would alter their surgical strategy based on the results of this testing. MAP is poorly recognized by ACPGBI members and therefore an opportunity exists for education among members. WHAT IS NEW IN THIS PAPER?: This study is the first paper to survey the ACPGBI membership on management practices in young-onset CRC. Members are poor in adopting preoperative testing, alter surgical strategy based on a familial syndrome, with a minority recognizing MAP. An opportunity to improve education on young CRC patients exists.

Hereditary Colorectal Cancer: Genetics and Screening

Colorectal cancer (CRC) is the third most common cancer and the third leading cause of cancer death in men and women in the United States. About 30% of patients with CRC report a family history of CRC. However, only 5% of CRCs arise in the setting of a well-established mendelian inherited disorder. In addition, serrated polyposis is a clinically defined syndrome with multiple serrated polyps in the colorectum and an increased CRC risk for which the genetics are unknown. This article focuses on genetic and clinical aspects of Lynch syndrome, familial adenomatous polyposis, and MUTYH-associated polyposis.

Total proctocolectomy for rectal cancer in Lynch syndrome: indications and considerations

SUMMARY 

Patients with Lynch syndrome and rectal cancer present a unique clinical challenge. Management of the primary rectal cancer and prophylactic removal of the colon should be considered. In patients requiring a mesorectal excision, a combined prophylactic colon removal can be considered. Although surveillance of the colon with frequent colonoscopies is an alternative, concerns of metachronous colon cancer development support prophylactic removal of the colon as an alternative. Since data are not available to confirm superiority of either approach, the final decision is greatly dependent upon a patient's wishes and preferences. Patients interested in pursuing simultaneous prophylactic colon removal can be offered total proctocolectomy with either ileal pouch anal-anastomosis as a sphincter-preserving alternative or a total proctocolectomy with end ileostomy.

Segmental vs extended colectomy in the management of hereditary nonpolyposis colorectal cancer: a systematic review and meta-analysis

AIM

The optimal surgical approach to the management of colorectal cancer in the setting of hereditary nonpolyposis colorectal cancer (HNPCC) is contentious. While some advocate total colectomy, others perform segmental resection followed by regular endoscopic surveillance. This systematic review evaluates the evidence for segmental colectomy (SC) and total (extended) colectomy (TC) in the management of HNPCC.

METHOD

Two major databases (PubMed and Cochrane) were searched using predefined terms. All original articles, published in English, comparing the oncological outcomes of SC and TC in HNPCC patients from January 1950 to July 2013 were included.

RESULTS

Eighty-four studies were identified. After applying exclusion criteria, six studies involving 948 patients were included (mean age 47.4 years, 51.8% male). SC was more commonly performed than TC (n = 780; 82.3%). Mean follow-up was 106.5 months. Metachronous high-risk adenomas were detected more often after SC, although the difference was not statistically significant (23.4% vs 9.6%; OR 2.258, P = 0.057). Metachronous cancers occurred more frequently after SC than after TC (23.5% vs 6.8%; OR 3.679, P < 0.005). However, there was no difference in overall survival (90.7% vs 89.8% for SC and TC, respectively; P = 0.085). Only one study reported operative mortality (0% in each group), there was no report of operative morbidity or functional outcome.

CONCLUSION

The optimal surgical approach in the management of HNPCC remains unclear. More adenomas and cancers occur after SC than after TC but there certainly is no evidence to suggest that more radical surgery leads to improved survival.

Comparative effectiveness in colon and rectal cancer

Treatment of colorectal cancer is becoming more uniform, with wider acceptance of standardized guidelines. However, areas of controversy exist where the appropriate treatment is not clear, including: should a segmental colectomy or a more extensive resection be performed in hereditary nonpolyposis colorectal cancer? should an asymptomatic primary cancer be resected in the presence of unresectable metastatic disease? what is the role of extended lymph node resection in colon and rectal cancer? are there clinically significant benefits for a robotic approach to colorectal resection versus a laparoscopic approach? This chapter will examine these issues and discuss how they may be resolved.

Prophylactic colectomy: Rationale, indications, and approach

Discerning the genetics of hereditary colorectal cancer syndromes has enabled a more individualized approach to preventing and treating colorectal cancers in affected patients and families. As these syndromes carry significant risk of colorectal cancer (nearly 100% in some cases), prophylactic colectomy is an important option for preventing cancer. This article addresses the rationale and indications for prophylactic colectomy in hereditary colorectal cancer syndromes, and provides insight into the details of surgical management.

Guidelines on genetic evaluation and management of Lynch syndrome: a consensus statement by the US Multi-Society Task Force on colorectal cancer

The Multi-Society Task Force, in collaboration with invited experts, developed guidelines to assist health care providers with the appropriate provision of genetic testing and management of patients at risk for and affected with Lynch syndrome as follows: Figure 1 provides a colorectal cancer risk assessment tool to screen individuals in the office or endoscopy setting; Figure 2 illustrates a strategy for universal screening for Lynch syndrome by tumor testing of patients diagnosed with colorectal cancer; Figures 3-6 provide algorithms for genetic evaluation of affected and at-risk family members of pedigrees with Lynch syndrome; Table 10 provides guidelines for screening at-risk and affected persons with Lynch syndrome; and Table 12 lists the guidelines for the management of patients with Lynch syndrome. A detailed explanation of Lynch syndrome and the methodology utilized to derive these guidelines, as well as an explanation of, and supporting literature for, these guidelines are provided.

Guidelines on genetic evaluation and management of Lynch syndrome: a consensus statement by the US Multi-society Task Force on colorectal cancer

The Multi-Society Task Force, in collaboration with invited experts, developed guidelines to assist health care providers with the appropriate provision of genetic testing and management of patients at risk for and affected with Lynch syndrome as follows: Figure 1 provides a colorectal cancer risk assessment tool to screen individuals in the office or endoscopy setting; Figure 2 illustrates a strategy for universal screening for Lynch syndrome by tumor testing of patients diagnosed with colorectal cancer; Figures 3,4,5,6 provide algorithms for genetic evaluation of affected and at-risk family members of pedigrees with Lynch syndrome; Table 10 provides guidelines for screening at-risk and affected persons with Lynch syndrome; and Table 12 lists the guidelines for the management of patients with Lynch syndrome. A detailed explanation of Lynch syndrome and the methodology utilized to derive these guidelines, as well as an explanation of, and supporting literature for, these guidelines are provided.

Surgical treatment of hereditary nonpolyposis colorectal cancer (HNPCC, Lynch syndrome)

The surgical management of the Lynch syndrome patient with colorectal cancer needs to be individualized. Because of the increased incidence of synchronous and metachronous colorectal neoplasms, most favor an extended resection at the time of diagnosis of colorectal cancer. Age of diagnosis, stage of the tumor, co-morbidities, surgical expertise, surgical morbidity, and patient wishes should be taken into account when considering a surgical procedure. There are no prospective randomized trials or retrospective trials suggesting that patients undergoing an extended procedure have a survival advantage compared to those undergoing segmental resection. In retrospective studies it has been demonstrated that patients undergoing extended procedures will develop less metachronous colorectal neoplasms and will undergo less subsequent surgical procedures related to colorectal cancer. In females abdominal hysterectomy and bilateral salpingoophorectomy should be considered at the time of surgery for colorectal cancer.

Results from an American Society of Colon and Rectal Surgeons survey on the management of young-onset colorectal cancer

BACKGROUND

Young patients with colorectal cancer (CRC) present a diagnostic and clinical challenge. The aim of our study was to survey the approaches to preoperative evaluation and clinical management of young patients with CRC by colorectal surgeons in North America.

METHODS

A standard electronic survey was sent to the members of the American Society of Colon and Rectal Surgeons. The survey polled management decisions in various clinical scenarios for CRC patients less than 50 years old. Survey responses were collated and analyzed.

RESULTS

One hundred ninety surgeons responded and 140 completed the entire survey (response rate 10%). Eighty percent of surgeons would offer preoperative genetic testing if the patient's family met the Amsterdam criteria compared to only 67% if the criteria were not met. Of those offering preoperative tumor testing, 48% test microsatellite instability, 19% mismatch repair protein expression by immunohistochemistry, and 24% offer both. Decisions regarding the extent of the resection for cancer were dependent on family history: Most members (86%) would perform a segmental colectomy for CRC in a patient without family history. Eighty-four percent of respondents would offer a total abdominal colectomy if preoperative tests indicated Lynch syndrome. When questioned about MYH-associated polyposis, only 27% recognized the appropriate diagnosis.

CONCLUSIONS

Among the American Society of Colon and Rectal Surgeons, family history influences preoperative testing and surgical management decisions. A significant portion of surgeons do not offer preoperative genetic testing, despite implications on operative management, postoperative surveillance, and screening of family members.

Candidate biomarkers for genetic and clinicopathological diagnosis of endometrial cancer

The recent increase in the frequency of endometrial cancer has emphasized the need for accurate diagnosis and improved treatment. The current diagnosis is still based on conventional pathological indicators, such as clinical stage, tumor differentiation, invasion depth and vascular invasion. However, the genetic mechanisms underlying endometrial cancer have gradually been determined, due to developments in molecular biology, leading to the possibility of new methods of diagnosis and treatment planning. New candidate biomarkers for endometrial cancer include those for molecular epigenetic mutations, such as microRNAs. These biomarkers may permit earlier detection of endometrial cancer and prediction of outcomes and are likely to contribute to future personalized therapy for endometrial cancer.

Risk of metachronous colon cancer following surgery for rectal cancer in mismatch repair gene mutation carriers

BACKGROUND

Despite regular surveillance colonoscopy, the metachronous colorectal cancer risk for mismatch repair (MMR) gene mutation carriers after segmental resection for colon cancer is high and total or subtotal colectomy is the preferred option. However, if the index cancer is in the rectum, management decisions are complicated by considerations of impaired bowel function. We aimed to estimate the risk of metachronous colon cancer for MMR gene mutation carriers who underwent a proctectomy for index rectal cancer.

METHODS

This retrospective cohort study comprised 79 carriers of germline mutation in a MMR gene (18 MLH1, 55 MSH2, 4 MSH6, and 2 PMS2) from the Colon Cancer Family Registry who had had a proctectomy for index rectal cancer. Cumulative risks of metachronous colon cancer were calculated using the Kaplan-Meier method.

RESULTS

During median 9 years (range 1-32 years) of observation since the first diagnosis of rectal cancer, 21 carriers (27 %) were diagnosed with metachronous colon cancer (incidence 24.25, 95 % confidence interval [CI] 15.81-37.19 per 1,000 person-years). Cumulative risk of metachronous colon cancer was 19 % (95 % CI 9-31 %) at 10 years, 47 (95 % CI 31-68 %) at 20 years, and 69 % (95 % CI 45-89 %) at 30 years after surgical resection. The frequency of surveillance colonoscopy was 1 colonoscopy per 1.16 years (95 % CI 1.01-1.31 years). The AJCC stages of the metachronous cancers, where available, were 72 % stage I, 22 % stage II, and 6 % stage III.

CONCLUSIONS

Given the high metachronous colon cancer risk for MMR gene mutation carriers diagnosed with an index rectal cancer, proctocolectomy may need to be considered.

Synchronous rectal and gastric cancer in a fighter pilot: aeromedical concerns

Synchronous cancer of the stomach and rectum is very rare. In a special population of pilots, especially fighter pilots, synchronous rectal and gastric cancer is much more uncommon. We herein report a case of synchronous carcinoma of the rectum and stomach. The patient was a 44-year-old male fighter pilot who complained with bloody stool and altered bowel habits. He was diagnosed with hereditary nonpolyposis colorectal cancer with a definite family history, and subsequently he underwent simultaneous low anterior resection and distal gastrectomy with D2 lymphadenectomy. Postoperative pathologic assessment showed a poorly differentiated gastric adenocarcinoma with signet ring cell components (pT2N1M0; stage IIb) and a moderately differentiated rectal adenocarcinoma with myxoid components (pT3N0M0; stage IIa). Both tumors showed positive expression of p53, Ki-67, VEGF, carcinoembryonic antigen, MRP, TS, P-gp, and TopoII, and negative expression of c-erbB2, CD34, CD31, D2-40, S-100, FVIII, MLH1, MSH2, and MSH6 oncoproteins. Six cycles of XELOX chemotherapy and 50 Gy/25 f radiotherapy were delivered postoperatively. Now, he has returned to his work under medical observation for about 6 months. From this patient's diagnosis and treatment, we think that the gene screening should be used in pilot selection. According to the result of gene screening, we can give pertinence examinations to the target organ of genes. It is very necessary for pilots to keep keen vigilance at gastrointestinal tumors because they have to face many high-risk factors in working. As to pilots, the selection of operation should be individualized.