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.

Historical review of Lynch syndrome

Lynch syndrome was formerly known as Hereditary Nonpolyposis Colorectal Cancer. Currently, these two nomenclatures each have their unique definitions and are no longer used interchangeably. The history of hereditary nonpolyposis colorectal cancer was first recognized formally in the literature by Henry Lynch in 1967. With advances of molecular genetics, there has been a transformation from clinical phenotype to genotype diagnostics. This has led to the ability to diagnose affected patients before they manifest with cancer, and therefore allow preventative surveillance strategies. Genotype diagnostics has shown a difference in penetrance of different cancer risks dependent on the gene containing the mutation. Surgery is recommended as prevention for some cancers; for others they are reserved for once cancer is noted. Various surveillance strategies are recommended dependent on the relative risk of cancer and the ability to intervene with surgery to impact on survival. Risk reduction through aspirin has shown some recent promise, and continues to be studied.

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.

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.

Total abdominal colectomy is cost-effective in treating colorectal cancer in patients with genetically diagnosed Lynch Syndrome

BACKGROUND

Lynch syndrome (LS) has a 80% lifetime risk of developing colorectal cancer and metachronous cancer. No studies have examined the quality adjusted life expectancy after SEG or TAC for LS patients, which this study was aiming for. If TAC offers a higher quality adjusted life year (QALY) to SEG in LS patients, preoperative diagnosis of LS is critical as it alters the recommended surgical procedure.

METHODS

A Markov decision tree was constructed using Treeage software to compare QALY of LS patients following SEG or TAC. Probabilities, cost, and utility were obtained from literature. Cost-effectiveness analyses were performed.

RESULTS

TAC dominates SEG as both the life-saving and cost-saving strategy. TAC dominated SEG on QALY (17.80 vs 17.13 QALY) for a cohort of LS patients diagnosed at an average of 30 year old and followed every 2 years after initial surgery.

CONCLUSIONS

We conclude that TAC as the primary surgical option for LS patients diagnosed with Stage I-III colon cancer is cost-effective. Further cost-effectiveness study is recommended to include extra-colonic malignancies in LS patients.

A Decision Analysis for Rectal-Sparing Familial Adenomatous Polyposis: Total Colectomy With Ileorectal Anastomosis Versus Proctocolectomy With IPAA

BACKGROUND

There are different approaches for the surgical management of rectal-sparing familial adenomatous polyposis with variable impacts on both quality of life and survival.

OBJECTIVE

The aim of this study was to quantify the trade-offs between total proctocolectomy with IPAA versus total colectomy with ileorectal anastomosis using decision analysis.

DESIGN

We created a disease simulation Markov model to simulate the clinical events after IPAA and ileorectal anastomosis for rectal-sparing familial adenomatous polyposis in a cohort of individuals at the age 30 years. We used available literature to obtain different transition probabilities and health-states utilities. The output parameters were quality-adjusted life-years and life-years. Deterministic and probabilistic sensitivity analyses were performed.

SETTINGS

A decision analysis using a Markov model was conducted at a single center.

PATIENTS

Patients with rectal-sparing familial adenomatous polyposis at age 30 years were included. Rectal-sparing familial adenomatous polyposis is defined as the presence of 0 to 20 polyps that can be removed endoscopically.

MAIN OUTCOME MEASURES

Quality-adjusted life-years were measured.

RESULTS

Our model showed that the mean quality-adjusted life-years for IPAA was 25.12 and for ileorectal anastomosis was 27.12 in base-case analysis. Mean life-years for IPAA were 28.81 and 28.28 for ileorectal anastomosis. A 1-way sensitivity analysis was performed for all of the parameters in the model. None of the deterministic sensitivity analyses changed the model results across the range of plausible values. Probabilistic analysis identified that, in 86.9% of scenarios, ileorectal anastomosis had improved quality-adjusted life-years compared with IPAA.

LIMITATIONS

The study was limited by characteristics inherent to modeling studies.

CONCLUSIONS

Ileorectal anastomosis was found to be preferable for patients with rectal-sparing familial adenomatous polyposis when quality of life is taken into consideration. This model was robust based on both deterministic and probabilistic sensitivity analyses. These data should be taken into consideration when counseling patients regarding a surgical approach in rectal-sparing familial adenomatous polyposis. See Video Abstract at http://links.lww.com/DCR/A715.

Current mismatch repair deficiency tumor testing practices and capabilities: A survey of Australian pathology providers

AIM & METHODS

An electronic survey of the Royal College of Pathologists of Australasia accredited pathology services was conducted to assess Lynch syndrome tumor screening practices and to identify barriers and capabilities to screen newly diagnosed colorectal and endometrial tumors in Australia.

RESULTS

Australia lacks a national policy for universal mismatch repair-deficient (dMMR) testing of incident colorectal and endometrial tumors cases. Routine Lynch syndrome tumor screening program for colorectal and/or endometrial tumors was applied by 95% (37/39) of laboratories. Tumor dMMR screening methods varied; MMR protein immunohistochemistry (IHC) alone was undertaken by 77% of 39 laboratories, 18% performed both IHC and microsatellite instability testing, 5% did not have the capacity to perform in-house testing. For colorectal tumors, 47% (17/36) reported following a universal approach without age limit, 30% (11/36) tested only "red flag" cases; 6% (3/36) on clinician request only. For endometrial tumors, 37% (12/33) reported clinician request generated testing, 27% (9/33) were screening only "red flag" cases, and 12% (4/33) carried out universal screening without an age criteria. BRAF V600E mutation testing of colorectal tumors demonstrating aberrant MLH1 protein expression by IHC was the most common secondary tumor test, with 53% of laboratories performing the test; 15% of laboratories also applied the BRAF V600E test to endometrial tumors with aberrant MLH1 expression despite no evidence for its utility. Tumor testing for MLH1 promoter methylation was performed by less than 15% laboratories.

CONCLUSION

Although use of tumor screening for evidence of dMMR is widely available, protocols for its use in Australia vary widely. This national survey provides a snapshot of the current availability and practice of tumor dMMR screening and identifies the need for a uniform national testing policy.

Molecular testing for Lynch syndrome in people with colorectal cancer: systematic reviews and economic evaluation

BACKGROUND

Inherited mutations in deoxyribonucleic acid (DNA) mismatch repair (MMR) genes lead to an increased risk of colorectal cancer (CRC), gynaecological cancers and other cancers, known as Lynch syndrome (LS). Risk-reducing interventions can be offered to individuals with known LS-causing mutations. The mutations can be identified by comprehensive testing of the MMR genes, but this would be prohibitively expensive in the general population. Tumour-based tests - microsatellite instability (MSI) and MMR immunohistochemistry (IHC) - are used in CRC patients to identify individuals at high risk of LS for genetic testing. MLH1 (MutL homologue 1) promoter methylation and BRAF V600E testing can be conducted on tumour material to rule out certain sporadic cancers.

OBJECTIVES

To investigate whether testing for LS in CRC patients using MSI or IHC (with or without MLH1 promoter methylation testing and BRAF V600E testing) is clinically effective (in terms of identifying Lynch syndrome and improving outcomes for patients) and represents a cost-effective use of NHS resources.

REVIEW METHODS

Systematic reviews were conducted of the published literature on diagnostic test accuracy studies of MSI and/or IHC testing for LS, end-to-end studies of screening for LS in CRC patients and economic evaluations of screening for LS in CRC patients. A model-based economic evaluation was conducted to extrapolate long-term outcomes from the results of the diagnostic test accuracy review. The model was extended from a model previously developed by the authors.

RESULTS

Ten studies were identified that evaluated the diagnostic test accuracy of MSI and/or IHC testing for identifying LS in CRC patients. For MSI testing, sensitivity ranged from 66.7% to 100.0% and specificity ranged from 61.1% to 92.5%. For IHC, sensitivity ranged from 80.8% to 100.0% and specificity ranged from 80.5% to 91.9%. When tumours showing low levels of MSI were treated as a positive result, the sensitivity of MSI testing increased but specificity fell. No end-to-end studies of screening for LS in CRC patients were identified. Nine economic evaluations of screening for LS in CRC were identified. None of the included studies fully matched the decision problem and hence a new economic evaluation was required. The base-case results in the economic evaluation suggest that screening for LS in CRC patients using IHC, BRAF V600E and MLH1 promoter methylation testing would be cost-effective at a threshold of £20,000 per quality-adjusted life-year (QALY). The incremental cost-effectiveness ratio for this strategy was £11,008 per QALY compared with no screening. Screening without tumour tests is not predicted to be cost-effective.

LIMITATIONS

Most of the diagnostic test accuracy studies identified were rated as having a risk of bias or were conducted in unrepresentative samples. There was no direct evidence that screening improves long-term outcomes. No probabilistic sensitivity analysis was conducted.

CONCLUSIONS

Systematic review evidence suggests that MSI- and IHC-based testing can be used to identify LS in CRC patients, although there was heterogeneity in the methods used in the studies identified and the results of the studies. There was no high-quality empirical evidence that screening improves long-term outcomes and so an evidence linkage approach using modelling was necessary. Key determinants of whether or not screening is cost-effective are the accuracy of tumour-based tests, CRC risk without surveillance, the number of relatives identified for cascade testing, colonoscopic surveillance effectiveness and the acceptance of genetic testing. Future work should investigate screening for more causes of hereditary CRC and screening for LS in endometrial cancer patients.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016033879.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Recent progress in Lynch syndrome and other familial colorectal cancer syndromes

The current understanding of familial colorectal cancer was limited to descriptions of affected pedigrees until the early 1990s. A series of landscape-altering discoveries revealed that there were distinct forms of familial cancer, and most were related to genes previously not known to be involved in human disease. This review largely focuses on advances in our understanding of Lynch syndrome because of the unique relationship of this disease to defective DNA mismatch repair and the clinical implications this has for diagnostics, prevention, and therapy. Recent advances have occurred in our understanding of the epidemiology of this disease, and the advent of broad genetic panels has altered the approach to germline and somatic diagnoses for all of the familial colorectal cancer syndromes. Important advances have been made toward a more complete mechanistic understanding of the pathogenesis of neoplasia in the setting of Lynch syndrome, and these advances have important implications for prevention. Finally, paradigm-shifting approaches to treatment of Lynch-syndrome and related tumors have occurred through the development of immune checkpoint therapies for hypermutated cancers. CA Cancer J Clin 2018;68:217-231. © 2018 American Cancer Society.

Efficacy of proximal colectomy for surgical management of right-sided first colorectal cancer in Lynch Syndrome mutation carriers

BACKGROUND

This study analyzes the occurrence of colorectal cancer (CRC) in Lynch syndrome (LS) mutation carriers, interval until diagnosis of metachronous CRC, and survival after proximal colectomy (PC) compared with total (TC) and subtotal colectomy (STC) for right-sided first CRC in LS mutation carriers.

METHODS

Sixty-four LS mutation carriers with right-sided first CRC treated with PC or TC + STC were confirmed by clinical records. Bivariate analyses were examined for significance and life tables were generated for risk of metachronous CRC and survival estimates following surgery.

RESULTS

One of 16 (6.3%) mutation carriers treated with TC + STC developed subsequent CRC compared with 13/48 (27%) treated by PC. There was no significant difference in survival estimates between PC compared with TC + STC through 25 years after surgery.

CONCLUSION

Risk of subsequent CRC and survival estimates following PC and TC + STC should be considered in surgical management of right-sided first CRC in LS mutation carriers.

Hereditary Colorectal Cancer Syndromes

Awareness of hereditary colorectal cancer syndromes is important to facilitate their identification because affected patients are at increased risk for early onset, synchronous, and metachronous colorectal malignancies, and certain extracolonic malignancies depending on the syndrome. Identification of an affected individual allows for screening and early interventions for patients and their at-risk kindred. Genetic counseling and testing is important to the care of these patients. As knowledge of the genetic basis of these syndromes grows, unique genotype-phenotype profiles allow clinicians to tailor surveillance and treatment strategies based on individual risk.

Surgical treatment of multiple sporadic colorectal carcinoma

Aim: Many aspects of the surgical management of multiple sporadic colorectal cancer syndrome, either synchronous and metachronous, remain to be cleared, in particular the prognostic influence of the extent of surgical resection. Method: A retrospective review was performed of patients diagnosed with multiple colorectal cancer from 1982 to May 2010. Clinical and pathologic data were collected and reviewed. Survival analysis was performed. Results: We identified 23 patients with multiple sporadic colorectal cancers, of which 8 had synchronous (SC) and 15 metachronous cancers (MC). Of the MC patients, 2 (13%) had the second cancer within 2 years, 4 (27%) in the time period of 2-5 years and 9 (60%) after 5 years. Twenty-one patients underwent multiple segmental resections; 2 patients underwent subtotal colectomy. The 5-year overall survival rate of SC and MC patients was 100% and 87% (p<0.001) respectively. The 5-year overall survival rate of multiple segmental resection patients and subtotal colectomy was 94% and 75% (p=0.655) respectively. Conclusion: Either synchronous and metachronous MSCRC patients showed good prognosis independently from to the extent of resection. Our results support a less aggressive biological behaviour allowing a more conservative management. Multiple segmental colorectal resections seem appropriate from an oncologic point of view in MSCRC patients. (www.actabiomedica.it)

Management strategies in Lynch syndrome and familial adenomatous polyposis: a national healthcare survey in Japan

Lynch syndrome (LS) and familial adenomatous polyposis (FAP) are major sources of hereditary colorectal cancer (CRC) and are associated with other malignancies. There is some heterogeneity in management strategies in Japan. We undertook a survey of management of hereditary CRC in hospitals that are members of the Japan Society of Colorectal Cancer Research. One hundred and ninety departments responded, of which 127 were from designated cancer care hospitals (DCCHs) according to the Japanese government. There were 25 488 operations for CRC in these departments in 2015. The DCCHs performed better with regard to usage of Japan Society of Colorectal Cancer Research guidelines, referring new CRC patients for LS screening, and having in‐house genetic counselors and knowledge of treatment for LS. There were 174 patients diagnosed with LS and 602 undergoing follow‐up in 2011–2015, which is fewer than the number expected from CRC operations in 2015. These numbers were not affected by whether the institution was a DCCH. Universal screening for LS was carried out in 8% of the departments. In contrast, 541 patients were diagnosed with FAP and 273 received preventive proctocolectomy/colectomy in 2011–2015. The DCCH departments undertook more surgery than non‐DCCH departments, although most of the management, including surgical procedures and use of non‐steroidal anti‐inflammatory drugs, was similar. Management of desmoid tumor in the abdominal cavity differed according to the number of patients treated. In conclusion, there was heterogeneity in management of LS but not FAP. Most patients with LS may be overlooked and universal screening for LS is not common in Japan.

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.

A systematic review and economic evaluation of diagnostic strategies for Lynch syndrome

BACKGROUND

Lynch syndrome (LS) is an inherited autosomal dominant disorder characterised by an increased risk of colorectal cancer (CRC) and other cancers, and caused by mutations in the deoxyribonucleic acid (DNA) mismatch repair genes.

OBJECTIVE

To evaluate the accuracy and cost-effectiveness of strategies to identify LS in newly diagnosed early-onset CRC patients (aged < 50 years). Cascade testing of relatives is employed in all strategies for individuals in whom LS is identified.

DATA SOURCES AND METHODS

Systematic reviews were conducted of the test accuracy of microsatellite instability (MSI) testing or immunohistochemistry (IHC) in individuals with CRC at risk of LS, and of economic evidence relating to diagnostic strategies for LS. Reviews were carried out in April 2012 (test accuracy); and in February 2012, repeated in February 2013 (economic evaluations). Databases searched included MEDLINE (1946 to April week 3, 2012), EMBASE (1980 to week 17, 2012) and Web of Science (inception to 30 April 2012), and risk of bias for test accuracy was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) quality appraisal tool. A de novo economic model of diagnostic strategies for LS was developed.

RESULTS

Inconsistencies in study designs precluded pooling of diagnostic test accuracy results from a previous systematic review and nine subsequent primary studies. These were of mixed quality, with significant methodological concerns identified for most. IHC and MSI can both play a part in diagnosing LS but neither is gold standard. No UK studies evaluated the cost-effectiveness of diagnosing and managing LS, although studies from other countries generally found some strategies to be cost-effective compared with no testing. The de novo model demonstrated that all strategies were cost-effective compared with no testing at a threshold of £20,000 per quality-adjusted life-year (QALY), with the most cost-effective strategy utilising MSI and BRAF testing [incremental cost-effectiveness ratio (ICER) = £5491 per QALY]. The maximum health benefit to the population of interest would be obtained using universal germline testing, but this would not be a cost-effective use of NHS resources compared with the next best strategy. When the age limit was raised from 50 to 60 and 70 years, the ICERs compared with no testing increased but remained below £20,000 per QALY (except for universal germline testing with an age limit of 70 years). The total net health benefit increased with the age limit as more individuals with LS were identified. Uncertainty was evaluated through univariate sensitivity analyses, which suggested that the parameters substantially affecting cost-effectiveness: were the risk of CRC for individuals with LS; the average number of relatives identified per index patient; the effectiveness of colonoscopy in preventing metachronous CRC; the cost of colonoscopy; the duration of the psychological impact of genetic testing on health-related quality of life (HRQoL); and the impact of prophylactic hysterectomy and bilateral salpingo-oophorectomy on HRQoL (this had the potential to make all testing strategies more expensive and less effective than no testing).

LIMITATIONS

The absence of high-quality data for the impact of prophylactic gynaecological surgery and the psychological impact of genetic testing on HRQoL is an acknowledged limitation.

CONCLUSIONS

Results suggest that reflex testing for LS in newly diagnosed CRC patients aged < 50 years is cost-effective. Such testing may also be cost-effective in newly diagnosed CRC patients aged < 60 or < 70 years. Results are subject to uncertainty due to a number of parameters, for some of which good estimates were not identified. We recommend future research to estimate the cost-effectiveness of testing for LS in individuals with newly diagnosed endometrial or ovarian cancer, and the inclusion of aspirin chemoprevention. Further research is required to accurately estimate the impact of interventions on HRQoL.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42012002436.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

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.

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.

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.

MUTYH-associated colorectal cancer and adenomatous polyposis

MUTYH-associated polyposis (MAP) was first described in 2002. MUTYH is a component of a base excision repair system that protects the genomic information from oxidative damage. When the MUTYH gene product is impaired by bi-allelic germline mutation, it leads to the mutation of cancer-related genes, such as the APC and/or the KRAS genes, via G to T transversion. MAP is a hereditary colorectal cancer syndrome inherited in an autosomal-recessive fashion. The clinical features of MAP include the presence of 10-100 adenomatous polyps in the colon, and early onset of colorectal cancer. Ethnic and geographical differences in the pattern of the MUTYH gene mutations have been suggested. In Caucasian patients, c.536A>G (Y179C) and c.1187G>A (G396D) mutations are frequently detected. In the Asian population, Y179C and G396D are uncommon, whereas other variants are suggested to be the major causes of MAP. We herein review the literature on MUTYH-associated colorectal cancer and adenomatous polyposis.

Quality of life after surgery for colon cancer in patients with Lynch syndrome: partial versus subtotal colectomy

BACKGROUND

Lynch syndrome is a disorder caused by mismatch repair gene mutations. Mutation carriers have a high risk of developing colorectal cancer. In patients with Lynch syndrome in whom colon cancer has been diagnosed, in general, subtotal colectomy instead of partial colectomy is recommended because of the substantial risk of metachronous colorectal cancer. However, the effect of more extensive surgery on quality of life and functional outcome is unknown.

OBJECTIVE

The aim of this study was to investigate quality of life and functional outcome in patients with Lynch syndrome after partial colectomy and subtotal colectomy.

DESIGN

This is a nationwide cross-sectional study in the Netherlands.

SETTINGS

Two quality-of-life questionnaires (Short Form-36 and The European Organization for Research and Treatment of Cancer Colorectal Cancer-specific Quality of Life Questionnaire Module) and a functional outcome questionnaire (Colorectal Functional Outcome) were used.

PATIENTS

Patients with Lynch syndrome who underwent surgery for colon cancer were included.

MAIN OUTCOME MEASURES

The primary outcomes measured were quality of life and functional outcome.

RESULTS

Questionnaires were sent to 192 patients with Lynch syndrome who underwent surgery for colorectal cancer. A total of 136 patients returned the questionnaire (response rate, 71%). Eighteen patients with rectal cancer, 9 patients with a permanent ileostomy, and 5 patients with an IPAA were excluded. Fifty-one patients underwent partial colectomy, and 53 underwent subtotal colectomy. None of the scales of the Short Form-36 survey showed a significant difference. Analysis of the Colorectal Functional Outcome questionnaire revealed that, after subtotal colectomy, patients have a significantly higher stool frequency (p ≤ 0.01) and a significantly higher score on stool-related aspects (p = 0.06) and social impact (p = 0.03). The European Organization for Research and Treatment of Cancer Colorectal Cancer-specific Quality of Life Questionnaire Module presented more problems with defecation after subtotal colectomy (p ≤ 0.01).

LIMITATIONS

Certain selection bias cannot be ruled out.

CONCLUSIONS

Although functional outcome is worse after subtotal colectomy than after partial colectomy, generic quality of life does not differ after the 2 types of surgery in Lynch syndrome. When discussing the options for surgery with the patient, all advantages and disadvantages of both surgical procedures, including quality of life and functional outcome, should be discussed.

Preoperative diagnosis of Lynch syndrome with DNA mismatch repair immunohistochemistry on a diagnostic biopsy

BACKGROUND

DNA mismatch repair immunohistochemistry on tumor tissue is a simple, readily available, and cost-effective method of identifying patients with Lynch syndrome in the postoperative setting. The aim of the study was to assess whether the mismatch repair status of a colorectal cancer can be confirmed by mismatch repair immunohistochemistry on preoperative biopsy.

DESIGN

Germline positive patients with Lynch syndrome were identified from a prospectively collected Familial Cancer Clinic database. Preoperative colorectal cancer biopsy specimens were obtained from the source pathology provider to generate a cohort of matched preoperative and postoperative specimens. The specimens were sectioned and stained for 4 mismatch repair proteins (MLH1, MSH2, MSH6, PMS2). An age-matched cohort to compare specimens was selected from Bethesda positive but mismatch repair immunohistochemistry negative patients. All slides were reviewed by a single blinded pathologist. The Wilson method was used to calculate a true underlying proportion of patients for whom the preoperative result matched the postoperative test result with a 95% confidence interval.

RESULTS

Of 128 germline positive mutation carriers, 40 patients (mean age 41, SD 11.3) had colorectal resections. Thirty-three preoperative specimens were retrievable and were matched with biopsies from 33 controls. The germline mutations included in the study were 8 MLH1, 19 MSH2, 3 MSH6, and 2 PMS2. In patients where germline positive status was known, sensitivity was 100% (95% CI 89.2-100) and specificity was 100% (95% CI 89.2-100). Identical sensitivity and specificity were observed in 33 age-matched patients. The sensitivity of the endoscopic biopsy in predicting germline status was 94.9% (95% CI 80.4-98.3).

CONCLUSION

The mismatch repair disease status of a colorectal cancer can be reliably confirmed by mismatch repair immunohistochemistry on a diagnostic colorectal cancer biopsy sample before definitive surgery. Ascertaining a diagnosis of Lynch syndrome before definitive surgery can influence surgical planning.

Clinical genetics of hereditary colorectal cancer

Colorectal cancer (CRC) is a common disease, and approximately 25% of patients have a familial component. High-penetrance singlegene germline mutations conferring a true hereditary susceptibility account for around 5% to 6% of all cases. Lynch syndrome is the most common hereditary form of colorectal cancer. Much of the hereditary component in the remaining familial cases of CRC is likely polygenic, and many of the genetic changes involved are as yet unidentified. This article addresses the most clinically important CRC genetic syndromes.

[Lynch syndrome: genetics and surgery]

Hereditary nonpolyposis colorectal cancer or Lynch Syndrome, caused by germinal mutations in mismatch deoxyribonucleic acid (DNA) repair genes, is the most common form of hereditary colorectal cancer. The identification of these individuals is not easy and is based on clinical and molecular criteria. A review is presented on the genetics and diagnosis in Lynch Syndrome, as well as on its surgical management and prevention.

Genetic counseling considerations in the evaluation of families for Lynch syndrome--a review

Lynch syndrome is the most common hereditary colorectal cancer syndrome and the most common cause of hereditary endometrial cancer. Identifying and evaluating families for Lynch syndrome is increasing in complexity due to the recognition that: family history-based clinical criteria lack sensitivity and specificity; genetic testing for Lynch syndrome continues to evolve as understanding of the molecular mechanisms underlying it evolves; and the Lynch syndrome phenotype encompasses multiple organ systems and demonstrates overlap with other hereditary cancer syndromes. This document is a summary of considerations when evaluating individuals and families for Lynch syndrome, including information on cancer risks, diagnostic criteria, tumor and genetic testing strategies, and the management of individuals with this condition.