Clinicopathological Features and Type of Surgery for Lynch Syndrome: Changes during the Past Two Decades

Universal Screening for Lynch Syndrome Compared with Pedigree-Based Screening: 10-Year Experience in a Tertiary Hospital

PURPOSE

Universal screening for Lynch syndrome (LS) refers to routine tumor testing for microsatellite instability (MSI) among all patients with colorectal cancer (CRC). Despite its widespread adoption, real-world data on the yield is lacking in Korean population. We studied the yield of adopting universal screening for LS in comparison with pedigree-based screening in a tertiary center.

MATERIALS AND METHODS

CRC patients from 2007-2018 were reviewed. Family histories were obtained and were evaluated for hereditary nonpolyposis colorectal cancer (HNPCC) using Amsterdam II criteria. Tumor testing for MSI began in 2007 and genetic testing was offered using all available clinicopathologic data. Yield of genetic testing for LS was compared for each approach and step.

RESULTS

Of the 5,520 patients, tumor testing was performed in 4,701 patients (85.2%) and family histories were obtained from 4,241 patients (76.8%). Hereditary CRC (LS or HNPCC) was present in 69 patients (1.3%). MSI-high was present in 6.9%, and 25 patients had confirmed LS. Genetic testing was performed in 41.2% (47/114) of MSI-high patients, out of which 40.4% (19/47) were diagnosed with LS. There were six additional LS patients found outside of tumor testing. For pedigree-based screening, Amsterdam II criteria diagnosed 55 patients with HNPCC. Fifteen of these patients underwent genetic testing, and 11 (73.3%) were diagnosed with LS. Two patients without prior family history were diagnosed with LS and relied solely on tumor testing results.

CONCLUSION

Despite widespread adoption of routine tumor testing for MSI, this is not a fail-safe approach to screen all LS patients. Obtaining a thorough family history in combination with universal screening provides a more comprehensive 'universal' screening method for LS.

Comparison of oncologic outcomes between patients with Lynch syndrome and sporadic microsatellite instability-high colorectal cancer

Purpose

Long-term oncologic differences in outcome between groups of patients with Lynch syndrome (LS) colorectal cancer (CRC) and sporadic CRC with microsatellite instability-high (MSI-H) are the focus of investigation in the current study.

Methods

Patients registered in the Korean Hereditary Tumor Registry and 2 tertiary referral hospitals treated for stage I–III CRC between 2005 and 2015 were retrospectively analyzed. Detection for both groups was performed using pedigree, microsatellite instability, and mismatch repair (MMR) gene testing. Multivariate analyses for overall survival (OS) and disease-free survival (DFS) were conducted.

Results

Cases of LS (n = 77) and sporadic CRC with MSI-H (n = 96) were identified. LS CRC patients were younger in age and displayed tumor sidedness, typically involving left-sided colon and rectum, compared to patients with sporadic CRC with MSI-H. OS and DFS were lower for LS CRC relative to CRC with MSI-H (OS, 72.7% vs. 93.8%, P = 0.001; DFS, 71.4% vs. 88.5%, P = 0.001). In multivariate analyses, tumor sidedness, stage, and chemotherapy were independent factors for OS and DFS. LS CRC was a prognostic factor for poorer OS (hazard ratio, 2.740; 95% confidence interval, 1.003–7.487; P = 0.049), but not DFS.

Conclusion

Our findings indicate that LS CRC is associated with poorer outcomes compared to sporadic CRC with MSI-H, presenting distinct clinical features. In view of the current lack of knowledge on genetic and molecular mechanisms, appropriate management taking into consideration the difficulty of identification of CRC with hypermutable tumors harboring heterogeneity is essential.

Deciding the operation type according to mismatch repair status among hereditary nonpolyposis colorectal cancer patients: should a tailored approach be applied, or does one size fit all?

BACKGROUND

Although extended colectomy (EC) was recommended for HNPCC patients, previous studies did not show significantly improved overall survival. Immunohistochemical (IHC) stain of mismatch repair (MMR) gene protein expression is now a feasible and reliable test clinically. Therefore, we tried to investigate whether we could use MMR IHC stain to select operation types in HNPCC patients.

PATIENTS AND METHODS

Between 1995 and 2013, 186 HNPCC patients were collected. Status of MMR protein expression, perioperative clinic-pathological variables and post-operative follow up status were analyzed by multivariate analyses.

RESULTS

Sixty-five percent (121 of 186) patients of these HNPCC patients demonstrated loss of at least one MMR protein. There were several significant differences existing between deficient MMR (dMMR) and proficient MMR (pMMR) subgroups in terms of clinic-pathological characteristics. With the average follow-up duration of 93.9 months, we observed significantly high risk of developing metachronous CRC between SC and EC subgroups (crude rate 8.5% vs. 0%, p = 0.035). However, no significant difference was observed among the presence of extra-colonic tumors (12.4% vs. 5.8%, p = 0.284). The positive and negative prediction rate of metachronous CRC in dMMR subgroup was 12.8 and 87.2% while 1.9 and 98.1% in the pMMR subgroup. Survival outcomes were significantly affected by MMR status and resection types by multivariate analysis. Significantly better OS in dMMR subgroup (HR = 0.479, 95% CI: 0.257-0.894, p = 0.021) comparing with pMMR subgroup was observed. However, significant improved DFS (HR = 0.367, 95% CI: 0.172-.0787, p = 0.010) but not significant for OS (HR = 0.510, 95% CI: 0.219-1.150, p = 0.103) for EC subgroup compared with SC subgroup. Differences existing among different subgroups by combing extent of resection and MMR status. In dMMR subgroup, SC, compared with EC, demonstrated significantly worse DFS by multivariate analyses (HR = 3.526, 95% CI: 1.346-9.236, p = 0.010) but not for OS (HR = 2.387, 95% CI: 0.788-7.229, p = 0.124), however, no significantly differences of OS and DFS in pMMR subgroup between SC and EC were found.

CONCLUSIONS

Significantly better overall survival and higher rate of metachronous CRC exist in dMMR subgroup of HNPCC patients comparing with pMMR subgroup. Extended colectomy significantly improved DFS and was thus recommended for dMMR subgroup but not pMMR subgroup of HNPCC patients.

Efficacy, functional outcome and post-operative complications of total abdominal colectomy with ileorectal anastomosis vs. segmental colectomy in hereditary non-polyposis colorectal cancer

The primary objective of the present study was to compare the choice of colectomy, i.e. total vs. segmental colectomy, in cases of hereditary non-polyposis colorectal cancer (HNPCC/lynch syndrome), and to assess the efficacy, oncological safety, functional outcome and post-operative complications of total abdominal colectomy with ileorectal anastomosis vs. segmental colectomy in HNPCC. A total of 289 patients who fulfilled the Amsterdam I and II criteria for HNPCC were included in the present study. The criteria for confirmation of the diagnosis were five micro-satellite markers, namely BAT25, BAT26, D2s123, d5S346 and D17S250. Group 1 included those patients who received their diagnosis in the years 2011–2013 and those in group 2 had been diagnosed in the years 2014–2016. The cohort had been subjected to two different types of surgery: i) Standard and extended surgery including total colectomy with ileal pouch anal anastomosis and subtotal colectomy and ii) segmental resection of the colon. Analysis of patient data indicated that in group 1, the extended resection was performed more frequently than in group 2 (68 vs. 34% of cases) and accordingly, segmental resection was less frequent (32 vs. 66%; P<0.001). In conclusion, the extensive rather than the segmental resection has been commonly performed several years ago, but at present, the surgical method of choice in cases of lynch syndrome is segmental resection. Trial registry no. QU/MR2011/CRC5, dated 21 March 2011.