Cancer: Lynch syndrome--how should colorectal cancer be managed?

Consequences of testing for mismatch repair deficiency of colorectal cancer in clinical practice

INTRODUCTION

Mismatch repair deficiency (dMMR) can be found in Lynch syndrome (LS)-associated colorectal carcinoma and in 15% of sporadic colorectal cancer (CRC). Outcome of MMR-deficiency testing is important for surgical decisions as extended colectomy is recommended in young LS-patients with CRC. Moreover, the finding of a dMMR tumour has consequences for the choices of adjuvant chemotherapy as MMR-deficient CRC is resistant to 5-fluorouracil (5-FU) monotherapy. Aims of our study are to evaluate whether MMR-deficiency testing leads to (1) identification of LS, (2) change in surgical treatment and (3) adjustment of systemic therapy in patients with dMMR CRC.

METHODS

We performed a multicentre, retrospective study, in a community hospital and a University Medical Centre. We included all CRC-patients between 2012 and 2016 who were tested for microsatellite instability. We collected clinical data such as gender, age, referral to clinical geneticist, surgical procedure and choice of chemotherapy.

RESULTS

We analysed 225 CRCs. Twenty-four (10.7%) of 225 CRC were MMR-deficient. Of the 24 patients with dMMR CRC, 18 (75%) were referred to the clinical geneticist and in nine (37%) patients a MMR mutation was identified. In one (4%) of the 24 patients, a subtotal colectomy was performed. In seven (35%) out of 20 MMR deficient patients, the chemotherapy regimen was adjusted.

CONCLUSIONS

The finding of a dMMR CRC had consequences for decisions on chemotherapy in a relative high proportion of patients. We recommend testing in all patients with CRC independent of age at diagnosis, as proper treatment decisions and genetic counselling are very important.

Subtotal Colectomy for Colon Cancer Reduces the Need for Subsequent Surgery in Lynch Syndrome

BACKGROUND

The risk of metachronous colorectal cancer is high after surgical resection for first colon cancer in Lynch syndrome.

OBJECTIVE

This study aimed to examine whether extended surgery decreases the risk of subsequent colorectal cancer and improves long-term survival.

DESIGN

This was a retrospective study.

SETTING

Data were collected from a nationwide registry.

PATIENTS

Two hundred forty-two Lynch syndrome pathogenic variant carriers who underwent surgery for a first colon cancer from 1984 to 2009 were included.

INTERVENTIONS

Patients underwent standard segmental colectomy (n = 144) or extended colectomy (n = 98) for colon cancer. Patients were followed a median of 14.6 up to 25 years.

MAIN OUTCOME MEASURES

Risk of subsequent colorectal cancer in either group, overall and disease-specific survival, and operative mortality were the primary outcomes measured.

RESULTS

Subtotal colectomy decreased the risk of subsequent colorectal cancer (HR, 0.20; 95% CI, 0.08-0.52; p = 0.001), compared with segmental resection. Subsequent colorectal cancer decreased in MLH1 carriers. The MSH2 carriers showed no statistical difference, possibly because of their small number. Disease-specific and overall survival within 25 years did not differ between the standard and extended surgeries (82.7% vs 87.2%, p = 0.76 and 47.2% vs 41.4%, p = 0.83). The cumulative risk of subsequent colorectal cancer was 20% in 10 years and 47% within 25 years after standard resection and 4% and 9% after extended surgery. The cumulative risk of metachronous colorectal cancer was 7% within 25 years after subtotal colectomy with ileosigmoidal anastomosis. One patient died of postoperative septicemia within 30 days after segmental colectomy.

LIMITATIONS

Data on surgical procedures were primarily collected retrospectively.

CONCLUSIONS

Lynch syndrome pathogenic variant carriers may undergo subtotal colectomy to manage first colon cancer and avoid repetitive abdominal surgery and to reduce the remaining bowel to facilitate easier endoscopic surveillance. It provides no survival benefit, compared with segmental colon resection. See Video Abstract at http://links.lww.com/DCR/A319.

Lynch syndrome risk management

Lynch syndrome has been known as hereditary non-polyposis colorectal cancer (HNPCC), and it is a dominantly inherited cancer syndrome caused by genetic mutations in cell mismatch repair genes, often leading to digestive system and female reproductive system tumors. At present, there is a high misdiagnosis rate for Lynch syndrome. This paper reviews the latest progress in Lynch syndrome risk management with regards to its monitoring, surgical treatment, pharmaceutical treatment, life style improvement and screening.

Clinical management of hereditary colorectal cancer syndromes

Hereditary factors are involved in the development of a substantial proportion of all cases of colorectal cancer. Inherited forms of colorectal cancer are usually subdivided into polyposis syndromes characterized by the development of multiple colorectal polyps and nonpolyposis syndromes characterized by the development of few or no polyps. Timely identification of hereditary colorectal cancer syndromes is vital because patient participation in early detection programmes prevents premature death due to cancer. Polyposis syndromes are fairly easy to recognize, but some patients might have characteristics that overlap with other clinically defined syndromes. Comprehensive analysis of the genes known to be associated with polyposis syndromes helps to establish the final diagnosis in these patients. Recognizing Lynch syndrome is more difficult than other polyposis syndromes owing to the absence of pathognomonic features. Most investigators therefore recommend performing systematic molecular analysis of all newly diagnosed colorectal cancer using immunohistochemical methods. The implementation in clinical practice of new high-throughput methods for molecular analysis might further increase the identification of individuals at risk of hereditary colorectal cancer. This Review describes the clinical management of the various hereditary colorectal cancer syndromes and demonstrates the advantage of using a classification based on the underlying gene defects.

The role of religious and existential well-being in families with Lynch syndrome: prevention, family communication, and psychosocial adjustment

This study explored the role of religious (RWB) and existential well-being (EWB) on psychosocial factors, support network characteristics, and screening practices in families with Lynch syndrome, also referred to as hereditary nonpolyposis colon cancer (HNPCC). Participants were individuals with Lynch syndrome associated cancers and their first-degree relatives at risk of inheriting an identified deleterious mutation. Analyses considered both family RWB and EWB norms and individual deviations from that norm. Analyses controlled for age, gender, cancer diagnosis, number of respondents, and network size. Higher family RWB was associated with increased depressive symptoms (p < .05) and avoidant cognitions (p < .05). Higher family EWB was related to decreased depression symptoms (p < .001). Higher family EWB was associated with fecal occult blood testing (p < .01), and family communication about genetic counselling and testing (p < .01). Analyses pointed to individual effects of EWB above and beyond family-level effects. Individuals with lower EWB than their family had lower perceived risk for colorectal cancer (p < .05), communicated disease risk information to less family members (p < .05), and were less likely to undergo recent colonoscopies (p < .05). Participants with lower EWB than their family also had higher cancer worry (p < .01) and increased depressive symptoms (p < .001). Findings indicate the importance of assessing individuals within the context of their family network and being aware of family characteristics which may impact individual adjustment to disease risk. Interventions considering family-level factors may provide efficient pathways to improving psychosocial factors, screening practices, communication about disease risk and genetic testing, and cancer prevention.

Haematuria in association with Lynch syndrome

A 40-year-old Caucasian male presented to the Emergency Department complaining of intermittent painless frank haematuria. Past medical history was significant for Hereditary Non-Polyposis Colon Cancer (HNPCC) and a prophylactic total colectomy. Computed tomography urogram showed thickening in the posterior wall of the bladder. Cystoscopy showed a small bladder mass. Histology showed a papillary urothelial neoplasm of low malignant potential. HNPCC, also known as Lynch Syndrome, is an autosomal dominant disorder responsible for 3-5% of colorectal cancers. There are certain cancers known to be associated with HNPCC; colorectal cancer, endometrial, ovarian, stomach, pancreas, biliary tract, small bowel, brain, renal pelvic and ureteric tumours, sebaceous gland adenomas and keratocanthomas. An association with bladder tumours is not well established.

Infiltration of Lynch colorectal cancers by activated immune cells associates with early staging of the primary tumor and absence of lymph node metastases

PURPOSE

Lynch syndrome colorectal cancers often lose human leukocyte antigen (HLA) class I expression. The outgrowth of clones with immune evasive phenotypes is thought to be positively selected by the action of cytotoxic T cells that target HLA class I-positive cancer cells. To investigate this hypothesis, we related the type and density of tumor lymphocytic infiltrate in Lynch colorectal cancers with their HLA class I phenotype and clinicopathologic stage.

EXPERIMENTAL DESIGN

HLA class I expression was assessed by means of immunohistochemistry. Characterization of tumor-infiltrating lymphocytes was carried out by using a triple immunofluorescence procedure that allowed the simultaneous detection of CD3-, CD8-, and granzyme B (GZMB)-positive cells. Additional markers were also used for further characterization of an elusive CD3(-)/CD8(-)/GZMB(+) cell population.

RESULTS

We discovered that high tumor infiltration by activated CD8(+) T cells correlated with aberrant HLA class I expression and associated with early tumor stages (P < 0.05). CD8(+) T cells were most abundant in HLA class I heterogeneous tumors (P = 0.02) and frequent in HLA class I-negative cases (P = 0.04) when compared with HLA class I-positive carcinomas. An elusive immune cell population (CD45(+)/CD8(-)/CD56(-)/GZMB(+)) was characteristic for HLA class I-negative tumors lacking lymph node metastases (P < 0.01).

CONCLUSIONS

The immune system assumes an important role in counteracting the progression of Lynch colorectal cancers and in selecting abnormal HLA class I phenotypes. Our findings support the development of clinical strategies that explore the natural antitumor immune responses occurring in Lynch syndrome carriers.