Familial cancer in an oncology clinic

Clustering of cancer among families of cases with Hodgkin Lymphoma (HL), Multiple Myeloma (MM), Non-Hodgkin's Lymphoma (NHL), Soft Tissue Sarcoma (STS) and control subjects

Background

A positive family history of chronic diseases including cancer can be used as an index of genetic and shared environmental influences. The tumours studied have several putative risk factors in common including occupational exposure to certain pesticides and a positive family history of cancer.

Methods

We conducted population-based studies of Hodgkin lymphoma (HL), Multiple Myeloma (MM), non-Hodgkin's Lymphoma (NHL), and Soft Tissue Sarcoma (STS) among male incident case and control subjects in six Canadian provinces. The postal questionnaire was used to collect personal demographic data, a medical history, a lifetime occupational history, smoking pattern, and the information on family history of cancer. The family history of cancer was restricted to first degree relatives and included relationship to the index subjects and the types of tumours diagnosed among relatives. The information was collected on 1528 cases (HL (n = 316), MM (n = 342), NHL (n = 513), STS (n = 357)) and 1506 age ± 2 years and province of residence matched control subjects. Conditional logistic regression analyses adjusted for the matching variables were conducted.

Results

We found that most families were cancer free, and a minority included two or more affected relatives. HL [(OR_adj (95% CI) 1.79 (1.33, 2.42)], MM (1.38(1.07, 1.78)), NHL (1.43 (1.15, 1.77)), and STS cases (1.30(1.00, 1.68)) had higher incidence of cancer if any first degree relative was affected with cancer compared to control families. Constructing mutually exclusive categories combining "family history of cancer" (yes, no) and "pesticide exposure ≥10 hours per year" (yes, no) indicated that a positive family history was important for HL (2.25(1.61, 3.15)), and for the combination of the two exposures increased risk for MM (1.69(1.14,2.51)). Also, a positive family history of cancer both with (1.72 (1.21, 2.45)) and without pesticide exposure (1.43(1.12, 1.83)) increased risk of NHL.

Conclusion

HL, MM, NHL, and STS cases had higher incidence of cancer if any first degree relative affected with cancer compared to control families. A positive family history of cancer and/or shared environmental exposure to agricultural chemicals play an important role in the development of cancer.

Hereditary colorectal cancer syndromes: molecular genetics, genetic counseling, diagnosis and management

Hereditary forms of colorectal cancer, as is the case with virtually all forms of hereditary cancer, show extensive phenotypic and genotypic heterogeneity, a phenomenon discussed throughout this special issue of Familial Cancer. Clearly, the family physician, oncology specialist, genetic counselor, and cancer geneticist must know fully the complexity of hereditary cancer syndromes, their differential diagnosis, in order to establish a diagnosis, direct highly-targeted surveillance and management, and then be able to communicate effectively with the molecular geneticist so that an at-risk patient's DNA can be tested in accord with the syndrome of concern. Thus, a family with features of the Lynch syndrome will merit microsatellite instability testing, consideration for immunohistochemistry evaluation, and mismatch repair gene testing, while, in contrast, a patient with FAP will require APC testing. However, other germline mutations, yet to be identified, may be important should testing for these mutations prove to be absent and, therein, unrewarding to the patient. Nevertheless, our position is that if the patient's family history is consistent with one of these syndromes, but a mutation is not found in the family, we still recommend the same surveillance and management strategies for patients from families with an established cancer-causing germline mutation. Our purpose in this paper is to provide a concise coverage of the major hereditary colorectal cancer syndromes, to discuss genetic counseling, molecular genetic evaluation, highly targeted surveillance and management, so that cancer control can be maximized for these high hereditary cancer risk patients.

Hereditary cancer syndrome diagnosis: molecular genetic clues and cancer control

Oncologists who are aware of the progress in hereditary cancer syndrome diagnosis, and, in particular, of how this effort may be effectively facilitated through a comprehensive family history in concert with molecular genetic studies, are in the envious position of designing highly targeted screening and management programs for the membership of these cancer-prone families. The Lynch syndrome is discussed as a clinical model wherein the presence of mismatch repair mutations provides a high level of diagnostic certainty for the initiation of targeted cancer screening and management. The familial atypical multiple mole melanoma-pancreatic cancer (FAMMM-PC) syndrome, on the other hand, provides another model with cancer-control potential. Given its phenotypic features of multiple atypical nevi, high total body mole count and cutaneous malignant melanoma, coupled with the integral association of PC in a subset of FAMMM kindreds with the CDKN2A germline mutation, this may result in a perhaps lower level of diagnostic certainty when compared with the Lynch syndrome. This knowledge may impact upon progress in the earlier diagnosis of melanoma and provide an impetus for creative diagnostic methods in PC, a disease that, at this time, demonstrates a mortality rate virtually identical to its incidence rate.

Pathogenesis and clinical management of hereditary non-polyposis colorectal cancer

BACKGROUND

Hereditary non-polyposis colorectal cancer (HNPCC) is an inherited genetic condition associated with microsatellite instability; it accounts for around 5 per cent of all cases of colorectal cancer. This review examines recent data on management strategies for this condition.

METHODS

A Medline-based literature search was performed using the keywords 'HNPCC' and 'microsatellite instability'. Additional original papers were obtained from citations in articles identified by the initial search.

RESULTS AND CONCLUSION

The Amsterdam criteria identify patients in whom the presence of an inherited mutation should be investigated. Those with a mutation should be offered counselling and screening. The role of prophylactic surgery has been superseded by regular colonoscopy, which dramatically reduces the risk of colorectal cancer. Screening for extracolonic malignancy is also advocated, but the benefits are uncertain. Chemoprevention may be of value in lowering the incidence of bowel cancer in affected patients, but further studies are required.

Hereditary nonpolyposis colorectal cancer: an update

Sporadic cancer develops approximately at 65 years of age. Epidemiologic data suggest that dietary factors probably are the most influential in colorectal carcinogenesis. In contrast, individuals who have relatives with colorectal neoplasia have an increased risk of these tumors themselves, which will appear earlier in life. The actual incidence of hereditary colorectal cancer is unknown. However, the incidence is much higher compared with well-known hereditary colorectal diseases, such as familial adenomatous polyposis.

OBJECTIVE

An overview of the recent progress in the field of both clinical and basic research on hereditary colorectal cancer must be made.

MATERIALS AND METHODS

Twenty-two family pedigrees were analyzed at Hamamatsu University School of Medicine, including the largest family pedigree in Japan, which contained 24 cases of colorectal cancer occurring over five generations. In 1995, when the International Symposium on Hereditary Cancer was held in Hamamatsu, 4,109 family pedigrees were investigated and analyzed, including 394 cases in 109 family pedigrees that met the Amsterdam Minimum Criteria. Information was collected by sending questionnaires to major hospitals in Japan. Basic updated data presented at the eighth and ninth International Collaborative Group on Hereditary Colorectal Cancer were also quoted.

RESULTS AND CONCLUSIONS

Because of the discovery of mismatch repair genes as that responsible for hereditary nonpolyposis colorectal cancer, modification of the Amsterdam Criteria is necessary. Replication error, as a mutator phenotype of mismatch repair genes, is a useful predictor of second primary malignancies. Surveillance or prophylactic surgery is still a controversial issue.

Hereditary nonpolyposis colorectal cancer (Lynch syndrome). An updated review

BACKGROUND

Hereditary nonpolyposis colorectal cancer (HNPCC) dates to Aldred Warthin's description of Family G a century ago. The phenotype features an excess of early onset colorectal carcinoma (CRC) with a propensity to involve the proximal colon, and a variety of extracolonic cancers, particularly carcinoma of the endometrium, ovary, stomach, small bowel, ureter, and renal pelvis. The recent discovery that HNPCC patients carry germline mutations in DNA mismatch repair genes has engendered great interest in the syndrome.

METHODS

This is a description of HNPCC based on the authors' experience with more than 170 families and a review of the world literature.

RESULTS

This review describes the genotypic and phenotypic features of HNPCC. The distinctive natural history of the syndrome is discussed in light of the recent discovery that ineffective DNA mismatch repair is the principal abnormality in affected individuals.

CONCLUSIONS

Clinical and molecular genetic knowledge about HNPCC is now available to physicians, and should enable them to provide highly targeted surveillance and management for patients with a high cancer risk. Genetic counseling can prove lifesaving. The study of HNPCC will likely contribute to knowledge about the causes and control of common forms of cancer in the general population.

Hereditary breast cancer

An overview is provided of the genetics of hereditary breast cancer, as well as the clinical aspects and the management of this disease. In September 1994 a new breast cancer gene, BRCA 2, was located and BRCA 1, discovered in 1990, was sequenced (Miki et al., 1994; Wooster et al., 1994). The implications of these discoveries are immense. Tests are now available to women who have a family history of breast cancer that can determine if they carry one of these defective genes. The genetic nurse specialist can play a huge role in counselling women who wish to have predictive testing and in advising them about screening and risk.

The risk of adenomatous polyps in asymptomatic first-degree relatives of persons with colon cancer

BACKGROUND & AIMS

Increasing evidence indicates that inherited susceptibility is important in the pathogenesis of colorectal neoplasia. The aim of this study was to clarify whether having only one first-degree relative with colorectal cancer increases the risk of developing adenomatous polyps and whether total colonoscopy is an appropriate screening measure in these patients.

METHODS

The frequency of such a history was evaluated in 397 asymptomatic patients who underwent total colonoscopy. Of these patients, 155 had colorectal polyps and the remaining 242 did not have polyps.

RESULTS

Among polyp cases, 27 of 155 (17.4%) had a positive history; among those without polyps, 12 of 242 (5.0%) had a positive history. Alternatively expressed, 27 of 39 patients (69%) with family history and 128 of 358 patients (36%) without family history had adenomas. The estimated risk for polyps associated with family history was 1.9. Among polyp cases, 14 of 27 patients (51.9%) with family history and 32 of 128 patients (25.0%) without family history had only proximal polyps (chi 2 test; P = 0.006; odds ratio, 3.2), In the same groups, frequency of high-grade dysplasia was 8 of 27 patients (29.6%) and 16 of 128 patients (12.5%), respectively (chi 2 test; P = 0.04; odds ratio, 2.9).

CONCLUSIONS

Relative to subjects with no family history, asymptomatic patients with one first-degree relative with colorectal cancer had nearly double the risk of developing adenomatous polyps, greater frequency of severely dysplastic lesions, and significantly higher frequency of proximal polyp location. This suggests that total colonoscopy screening is indicated in these subjects.

Informational needs of individuals and families with hereditary cancers

Individuals and families with hereditary cancers have informational needs that differ, depending on the availability of testing for increased hereditary risk and major focus of concern (reproductive decision-making or risk to self). Cancer risk counseling helps individuals understand risk information so they can make decisions appropriate to their lives and value systems.

Hereditary carcinoma of the ovary and associated cancers: a study of two families

Increasing attention has been given to host factors in the etiology of ovarian carcinoma. Case/control studies have shown a significant excess of this disease among primary relatives of ovarian cancer affected. Pedigree studies have demonstrated its occurrence on a site-specific basis, in association with carcinoma of the breast (breast/ovarian carcinoma syndrome), and in other hereditary disorders. The complexity of this heterogeneity clearly warrants more intensive family studies. We have described genetic and clinicopathologic nuances in two extended ovarian cancer-prone families. The absence of premonitory physical stigmata and/or biomarkers which signify the cancer-prone genotype compels the physician to employ the best posits from the pedigree to identify those patients who are at inordinately high risk for ovarian and/or syndrome-associated cancer so that surveillance strategies can be more focused. Because of limitations of current surveillance strategies for the early detection of ovarian carcinoma, the clinician's responsibility includes the identification and counseling of candidates for prophylactic oophorectomy.

Colonoscopic screening of persons with suspected risk factors for colon cancer. I. Family history

A family history of colorectal cancer is believed to place persons at increased risk for development of the disease. It is unclear, however, how "strong" a family history must be to increase this risk or to make colonoscopic screening appropriate. We performed initial colonoscopy in 154 asymptomatic subjects whose only suspected risk factor was one or two first-degree relatives with colorectal cancer; 48 of these subjects also had affected second- and third-degree relatives. We found 45 adenomas in 28 subjects (18%). One subject had a 3-cm villous adenoma. In 6 subjects, the most advanced findings were tubular adenomas 5-9 mm in diameter; in 21 subjects, we found only tubular adenomas that were 2-4 mm in diameter. The prevalence of adenomas increased significantly with age of subjects (p less than 0.01). Although the overall prevalence of colorectal neoplasms in our group was no greater than might be expected in the general population, subjects with two first-degree relatives tended to have more diminutive adenomas than those with one such relative. Our findings suggest that colonoscopy is not an appropriate first step in screening persons with one affected first-degree relative. For those with more complex family histories, more data are needed--particularly on the prevalence of advanced neoplasms--to determine whether a screening technique that is less costly and less invasive than colonoscopy may be adequate.

Frequency of hereditary colorectal carcinoma

The frequency of hereditary colorectal carcinoma was evaluated in a study group consisting of all colorectal carcinoma patients (n = 468) diagnosed in one Finnish county (0.25 million inhabitants) during the period 1970-1979. The cancer family syndrome type of hereditary nonpolyposis colorectal carcinoma emerged as the most common verifiable risk factor for colon cancer involving 3.8%-5.5% of all colorectal carcinoma patients in this study. The frequencies of familial adenomatosis and ulcerative colitis were 0.2% and 0.6%, respectively. As the diagnostic method of this study was based on the family history of the patients, only those families with inherited cancer cases in two or more generations could be identified. The cancer family syndrome cannot be diagnosed on the basis of a single patient, and so the observed frequency of 4%-6% for the syndrome may still represent an underestimate. The patients with cancer family syndrome were young, accounting for 29%-39% of the patients under 50 yr of age, and their tumors were located predominantly (65%) in the right hemicolon. The high frequency of hereditary cases among colorectal carcinoma patients indicates the importance of studying the family history of every new patient.

Colorectal cancer in patients with family history

The relationship between first degree family history of colorectal cancer and some pathological and clinical features was investigated in 302 patients affected by large bowel carcinoma. Patients with inherited forms of polyposis of the large bowel were excluded. Thirty-six (11.9%) had at least one close relative affected by intestinal cancer. No relationship between family history and pathological features (anatomic distribution, stage and grading) was found. Moreover no difference in prognosis between patients with a family history and those without was shown. These results suggest no relationship between a first degree family history and the natural history of the disease.

Genetics of site specific colon cancer: a family study

In a kindred of 46 individuals of an Indian Sikh family with no history of consanguinity, 8 suffered from site specific colon (caecum) cancer (not associated with polyposis). The clinical features in the affected kindred were indicative of a "cancer family syndrome". The study of the family depicted an autosomal dominant transmission pattern of site specific colon cancer, with probably 100% penetrance in the affected individuals. A low percentage of mitotic index (MI) was observed in the two probands who were available for the study. No structural or numerical chromosomal aberrations were observed in either case. It is probable that the gene responsible in this family could have begun by mutation at the germ cell level in the 1st generation and remained in a heterozygous condition in the affected individuals.

Natural history of hereditary cancer of the breast and colon

The natural history of 106 patients from eighteen families manifesting hereditary breast cancer syndromes, and 117 affected patients from twenty families manifesting nonpolyposis hereditary colon cancer were evaluated. Findings were compared with the American College of Surgeons (ACS) long-term audits for breast and colon cancer respectively. The cardinal features of hereditary cancer were observed within the study group, including: (1) a significant younger age of onset (49 years, breast; 46 years, colon); (2) an excess of proximal lesions in the hereditary colon series (49%); and (3) an excess of bilaterality in the hereditary breast cancer patients. The clinical stage at presentation was similar for the hereditary and ACS audit patients. Five-year survival was significantly improved (P less than .05) for both hereditary cancer populations as compared to the ACS audits (67% hereditary breast cancer and 52% nonpolyposis hereditary colon cancer). Improved survival in hereditary colon and breast cancer patients may have a bearing on the design of future clinical protocols.