Prevalence of hereditary nonpolyposis colorectal carcinoma (HNPCC)

Survival, surgical management and perioperative mortality of colorectal cancer in the 21-year experience of a specialised registry

BACKGROUND AND AIMS

A general improvement of colorectal cancer prognosis has been observed. Reasons of this more favourable trend are diffusion of screening, advancements in molecular biology, new developments in chemotherapy and surgical techniques. Through the data of a colorectal cancer registry, we purposed to evaluate changes in surgical procedures for colorectal neoplasms and to analyse trends of perioperative mortality.

PATIENTS AND METHODS

Patients with colorectal cancer were registered from 1984 to 2004. The main surgical procedures were recorded and classified. Perioperative mortality was defined as death of patients within 1 month since the operation.

RESULTS

Regression analysis showed an increase over time of right and left hemicolectomy. Both colectomy and endoscopic polypectomy showed significant rise over time. In contrast, abdominoperineal operations dropped during the study period. A similar decrease was observed for palliative surgery. Perioperative mortality declined from 7-11% to 3-6% of all operations; main factors associated with perioperative mortality were presence of comorbidities, increasing age and advanced stage.

CONCLUSION

The better prognosis of patients with colorectal cancer was associated with changes of surgical techniques, with a tendency to prefer large operations over limited resections. Perioperative mortality showed a gradual decrease and is at present in the order of 3% to 6% of all operations.

An economic viewpoint on alternative strategies for identifying persons with hereditary nonpolyposis colorectal cancer

PURPOSE

There is uncertainty regarding the optimal strategy for identifying mutation carriers among those with hereditary nonpolyposis colorectal cancer (HNPCC).

METHODS

We used decision analysis to compare the cost-effectiveness of 4 strategies among those with newly diagnosed colon cancer: (1) clinical and family history followed by microsatellite instability testing and germline testing (Bethesda guidelines); (2) universal microsatellite instability testing; (3) germline testing of those who meet clinical and family history criteria; and (4) universal germline testing.

RESULTS

The added cost per year of life saved (YLS) for each strategy was as follows: (1) 11,865 US dollars/YLS, (2) 35,617 US dollars/YLS, (3) 49,702 US dollars/YLS, and (4) 267,548 US dollars/YLS.

CONCLUSIONS

The Bethesda guidelines are the most cost-effectiveness approach to screen persons for HNPCC.

Report of 16 kindreds and one kindred with hMLH1 germline mutation

AIM: To analyze the diagnosis and treatment of 16 hereditary nonpolyposis colorectal cancer (HNPCC) kindreds, and to report the first kindred with hMLH1 germline mutation in Mainland China.

METHODS: The diagnosis, treatment and follow-up study of 16 HNPCC kindreds were retrospectively reviewed. Data concerning site of the malignant tumor, age at the diagnosis, history of synchronous and/or metachronous cancer, and histopathology of tumors were recorded. All treatments had won formal consent. PCR and SSCP were used to screen the coding region of hMLH1 and hMSH2 genes. Variant bands were sequenced by a 377 DNA sequencer.

RESULTS: Among sixteen kindreds, sixty-eight patients had a mean age of 50.8 years, including twenty-one multiple cancer patients and forty-six colorectal cancer patients (metachronous colorectal cancers in sixteen). A total of one hundred and one malignant neoplasms were found in these sixty-eight patients, including 50 colonic, 17 rectal, 11 gastric, 7 endometrial, and 4 esophageal cancers. 39.5% colorectal patients had metachronous cancers within ten years who needed reoperations. A germline G265T nonsense mutation was found in the third exon of hMLH1, resulting in a stop codon and truncated protein. Three phenotypically normal family members were also found to carry the mutated gene.

CONCLUSION: HNPCC is a typical auto-dominant hereditary disease, the main characteristics include early onset and frequency of cancers; predominance of colorectal, especially right-sided colon cancers; frequency of multiple primary cancers (especially colorectal cancers). Segmental resection for colorectal cancers is not eligible for colorectal cancer patient in HNPCC kindreds. Intensive follow-up is essential for all patients and possible gene carriers. The first HNPCC kindred with hMLH1 gene germline mutation was identified in Mainland China, and three phenotypically normal family members were found to be carriers of the mutated gene. The G265T germline (nonsense) mutation in the third exon of hMLH1 found here had not been reported previously in the literature.

Problems in the identification of hereditary nonpolyposis colorectal cancer in two families with late development of full-blown clinical spectrum

The recognition of Hereditary Nonpolyposis Colorectal Cancer (HNPCC) remains difficult despite the most recent advancements of molecular biology and technology. We describe two families with early onset of cancer but no suspicion of hereditary tumors; during follow-up, both families developed a tumor spectrum highly suggestive of HNPCC, thus emphasizing the importance of family history for a proper identification of hereditary tumors or cancer aggregation. Microsatellite instability was negative in tumors from both families and, as expected, no germline mutations of the major DNA mismatch repair genes (MSH2 and MLH1) could be detected. Suspicion of the disease at the time of proband's lesion might have led to prevention, or early diagnosis, of at least three malignant tumors. We conclude that a possible genetic origin should always be suspected in individuals with early-onset neoplasms of the large bowel and probably of other organs such as the endometrium, small bowel, and urothelium, even when the initial pedigree does not show marked aggregation of cancers or vertical transmission.

Rectal cancer risk in hereditary nonpolyposis colorectal cancer after abdominal colectomy. International Collaborative Group on HNPCC

OBJECTIVE

The authors analyzed the incidence of rectal cancer in patients with hereditary nonpolyposis colorectal cancer (HNPCC) after an abdominal colectomy.

SUMMARY BACKGROUND DATA

The treatment of choice for a newly diagnosed patient with HNPCC with colon cancer is an abdominal colectomy. The incidence of rectal cancer after abdominal colectomy in HNPCC is not known.

MATERIALS AND METHODS

A questionnaire was mailed to all International Collaborative Group on HNPCC members to identify patients in whom rectal cancer developed after total, subtotal or completion colectomy. Statistics were performed using the log-rank test, Kaplan-Meier method, and Cox's proportional hazards model.

RESULTS

Rectal cancer developed in 8 (11%) of 71 patients a median of 158 months (range, 38-282 months) from their primary procedure. Of these eight patients, adenomas in the rectal mucosa developed in five at risk either before (4) or synchronous (1) with the diagnosis of rectal cancer. At the time of diagnosis of rectal cancer, six of eight patients were being observed. Age at first procedure and whether the patient was under surveillance were the only significant variables (p < 0.05) in the multivariate analysis in terms of rectal cancer risk. The risk of developing rectal cancer was estimated to be 3% every 3 years after abdominal colectomy for the first 12 years.

CONCLUSIONS

The risk of rectal cancer in patients with HNPCC after an abdominal colectomy is approximately 12% at 12 years. Age at first surgical procedure and surveillance correlated with rectal cancer risk. Aggressive endoscopic surveillance of the rectum should be performed after abdominal colectomy.

Establishment of a hereditary nonpolyposis colorectal cancer registry

INTRODUCTION

Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant condition characterized by early age of onset colorectal cancer, right-sided predominance, excess of synchronous and metachronous colonic neoplasms, and extracolonic cancers. The purpose of this study is to report clinical characteristics of HNPCC families in our registry.

METHODS

This is a retrospective review of medical records of patients with a significant history of colorectal cancer and interviews with their families.

RESULTS

Three hundred one people with cancer in 40 HNPCC families were identified. In 284 of 301 (94 percent) people, 363 cancers were identified. Colorectal cancer only was identified in 182 people (64 percent) and, in conjunction with extracolonic tumors, in another 31 people (11 percent). Extracolonic cancer alone was noted in 71 people (25 percent). Median age at diagnosis of colorectal cancer was 48 (range, 17-92) years. In patients with documented pathology, right-sided tumors predominated (55 percent), synchronous and metachronous tumors were noted in 53 percent, and synchronous of metachronous adenomas were documented in 51 percent of people. Generational anticipation was also noted.

CONCLUSION

This study demonstrates and confirms characteristics that have been described in HNPCC. Namely, early age of onset of colorectal cancer, right-sided predominance, multiple synchronous and metachronous neoplasms, increased extracolonic cancers, and generational anticipation.

Frequency and clinical features of multiple tumors of the large bowel in the general population and in patients with hereditary colorectal carcinoma

BACKGROUND

Reports on the frequency of multiple carcinomas of the colon and rectum have varied from 3-4% to more than 10% of all tumors of the large bowel.

METHODS

We reviewed the files of a specialized colorectal cancer registry with the following objectives: a) to determine the frequency of multiple tumors (synchronous or metachronous) in the general population; b) to compare these values with those observed in patients with hereditary nonpolyposis colorectal carcinoma (HNPCC); and c) to evaluate the clinical outcome of patients with multiple tumors and the role of other clinical parameters in the development of these neoplasms.

RESULTS

From 1984 to 1992, 53 patients with multiple tumors (of 1298 registered patients, 4%) had large bowel carcinoma; 33 (2.5%) were synchronous and 20 (1.5%) metachronous. The total number of multiple colorectal carcinomas was 95, which was 7% of all registered colorectal carcinomas (1337 carcinomas in 1298 patients). Multiple tumors occurred significantly more often in patients with HNPCC than in those with sporadic carcinomas (P < 0.001); this increased prevalence was more marked for metachronous lesions, which occurred almost 4 times more often in patients with HNPCC (5.8% vs. 1.3%; P < 0.001). The average interval of time between the first and the second malignancy was 8.7 years; there was no significant difference between hereditary and sporadic tumors. Patients with synchronous tumors did not show appreciable differences in survival when compared with individuals who had single neoplasms. In contrast, a poor clinical outcome was observed in patients with metachronous tumors after the development of the second carcinoma. Finally, polypoid adenomas of the large bowel were found significantly more often in patients with multiple primary tumors than in those with a single tumor.

CONCLUSIONS

These results emphasize the importance of preoperative pancolonoscopy for the identification of possible synchronous tumors (both benign and malignant) and long-lasting endoscopic follow-up for the detection of recurrent or metachronous lesions. The conclusions are even more pertinent for patients with HNPCC, whose risk of metachronous tumors is significantly higher than that of patients with sporadic carcinoma.

Hereditary nonpolyposis colorectal cancer: review of clinical, molecular genetics, and counseling aspects

Lynch syndrome, or hereditary nonpolyposis colon cancer (HNPCC), is an autosomal-dominant disease accounting for approximately 1-5% of all colorectal cancer cases. Due to the lack of pathognomonic morphological or biomolecular markers, HNPCC has traditionally posed unique problems to clinicians and geneticists alike, both in terms of diagnosis and clinical management. Recently, novel insight into the pathogenesis of this syndrome has been provided by the identification of its molecular basis. In HNPCC families, germline mutations in any of four genes encoding proteins of a specialized DNA repair system, the mismatch repair, predispose to cancer development. Mutations in mismatch repair genes lead to an overall increase of the mutation rate and are associated with a phenotype of length instability of microsatellite loci. The present report summarizes the clinicopathological aspects of HNPCC and reviews the most recent molecular and biochemical findings.

Use of gene tests to detect hereditary predisposition to cancer: what do we know about cost effectiveness?

Mutations in 4 genes associated with DNA repair have been shown to be associated with hereditary non-polyposis colon cancer (HNPCC) in families which display unusually high risk for colorectal cancer. Laboratory tests for mutations in these genes will soon be commercially available, raising the possibility that population-wide gene testing to identify individuals with an inherited susceptibility to colorectal cancer could be conducted. The purpose of our report is to explore the economic implications of conducting a program of population-wide screening for HNPCC compared with alternative programs which would be restricted to families already known to be at high risk for HNPCC. Rather than provide a definitive answer to these questions, our purpose is to indicate priority areas of research which need to be conducted before such a definitive analysis can be done. An exploratory analysis has been conducted to determine which factors are most important in determining the cost-effectiveness of a genetic testing program for HNPCC. The base case analysis focuses on current uncertainty about the population prevalence of the HNPCC genotype and phenotype, factors which are central to the cost-effectiveness of population-wide screening. Uncertainty in parameters related to the cost and effectiveness of screening and preventive interventions for HNPCC were explored using additional sensitivity analyses. Favorable levels of cost-effectiveness for population-wide screening are achieved only when the most favorable assumptions about HNPCC prevalence and the cost and effectiveness of screening and preventive interventions are made.