Familial cancer of the colon and rectum

Genetics, inheritance and strategies for prevention in populations at high risk of colorectal cancer (CRC)

Hereditary forms of colorectal cancer account for less than 5 % of colorectal cancer but attract disproportionate attention because they offer an opportunity for effective surgical prophylaxis, influence the health of the wider family and give insight into the critical pathways of carcinogenesis. Familial Adenomatous Polyposis (FAP) due to loss of the APC gene and Lynch syndrome or Hereditary Non-Polyposis Colon Cancer (HNPCC) due to breakdown in MisMatch Repair are the principal syndromes of broader interest and both have been the subject of chemoprevention trials. There has been a longstanding interest in non-steroidal anti inflammatories in FAP where trials have shown regression of polyps with the "pro drug"sulindac and the selective COX2 inhibitors though impact on long-term cancer risk is not confirmed. The CAPP1 trial focused on two interventions in a factorial design, aspirin and resistant starch or fermentable fibre. Resistant starch is not absorbed in the small intestine and undergoes colonic fermentation to short-chain fatty acids including butyrate which have anti-cancer effects. Polyposis registry clinicians across Europe recruited adolescents with FAP to receive aspirin (600 mg as 2 tablets/d) and/or 30 g as 2 sachets/d in a 1:1 blend of potato starch and high amylose maize starch [Hylon VII]) with placebo control for at least a year or until surgery before age 21. Fifty-nine percent (133/227) of recruits had a baseline and at least one other endoscopy. After a median of 17 months , the primary endpoint of a risk of an increased polyp number in the rectum and sigmoid colon was not significantly reduced in either treatment group with relative risks of 0.77 (aspirin; 95 % CI, 0.54-1.10;) and 1.05 (RS; 95 % CI, 0.73-1.49. The diameter of the largest polyp detected tended to be smaller in the aspirin arm. The planned subgroup analyses of patients who elected to continue on study for more than one year found a significant reduction in the size of the largest polyp in the aspirin versus non-aspirin group (p = 0.02), Mean crypt length decreased significantly over time on study in the two combined RS groups, compared with the two combined non-RS groups (p < 0.0001 for interaction), in a model of the interaction between intervention and time. In CAPP2, 1009 Lynch syndrome gene carriers were recruited from 43 international centres. 937 commenced intervention: 600 mg enteric coated aspirin and/or 30grams of the resistant starch Novelose in a 2 by 2 factorial placebo controlled design. After a mean of 29 months, intervention, there was no evidence that either agent influenced development of colonic neoplasia. However, the design included double blind follow-up for at least 10 years. After a mean of 55.7 months, and despite regular colonoscopy and polyp removal, 48 recruits developed CRC. Of these, 18 received aspirin and 30 received AP; the HR for CRC for aspirin was 0.63 (CI 0.35-1.13, p = 0.12). Five of the 48 people who developed CRC each had two primary colon cancers. Poisson regression analysis to allow for multiple primary events indicated a protective effect: IRR 0.56 (CI 0.32-0.99, p = 0.05). For those who took aspirin (or AP) for a minimum of 2 years (per protocol) the HR was 0.41 (CI 0.19-0.86 p = 0.02) and the IRR, 0.37 (CI 0.18-0.78 p = 0.008). Combined analysis of all LS cancers including CRC revealed a similar effect. On intention to treat analysis, the HR was 0.65 (CI 0.42-1.00, p = 0.05 and IRR was 0.59 (CI 0.39-0.90 p = 0.01), while the Per Protocol analysis HR was 0.45 (CI 0.26-0.79 p = 0.005,) and IRR was 0.42 (CI 0.25-0.72, p = 0.001). Adverse events in the aspirin and placebo groups were similar with 11 significant gastrointestinal bleeds or ulcers in the aspirin group and 9 in the placebo group. The evidence is now sufficient to recommend aspirin to all Lynch syndrome gene carriers. CAPP3 will recruit 3000 gene carriers into a dose inferiority study to test the relative benefits of 100mg, 300 or 600mg daily doses.

Characteristics of familial colon cancer in a large population data base

Early age onset and proximal colonic location are two specific characteristics of colon cancer which have been used clinically to assess the risk that an individual case is of familial rather than sporadic origin. This practice derives from the observation that these characteristics are typical of the rare, nonpolyposis inherited colorectal cancer syndromes. This study examines these two characteristics in cases of common colon cancer to determine whether they actually distinguish individuals at increased risk for familial colorectal cancer. Familial clusters of colon cancer in the Utah Population Data Base were examined. Common colon cancers were found to cluster excessively in families; however, the measure of familial clustering for distal colonic cases was increased to the same degree as proximal colonic cases. Early age onset was likewise not a distinguishing factor of familial cases. These results suggest that factors other than those that predispose to the rare syndromes are important in determining familial risk for common colon cancers, and that the absence of these two clinical features should not suggest the absence of familial risk of colorectal cancer.

A study of familial non-polypotic colorectal cancer

The family history of colorectal cancer was examined in 601 patients with non-polypotic colorectal cancer. 33 (5.5 per cent) of these patients were found to have a family history. Colorectal cancer was found significantly more often in the families of those patients with the disease rather than in those with gastric cancer (5.5 per cent vs 3.0 per cent). The mean age was younger by five years in the patients with a family history than in those with no family history. The incidence of young patients, multiple cancers, and other cancers in relatives was significantly higher in the patients with a family history than in those without. No significant difference in cancer sites between the two groups was seen, however, there was a preponderance of right colon cancers in the young patients with a family history. There was one particular patient with seven affected relatives in his family. In this patient, an early age of onset, the presence of multiple cancers, including a right colon cancer, the occurrence of metachronous other cancers and the fact that one of his relatives was accidentally found to have an occult colon cancer were noteworthy. It is important to survey the family members of patients, especially the young ones, where there is a family history of colorectal cancer.

Report of a family with hereditary site-specific colon cancer

A large family with a high prevalence of colorectal cancer, presenting the major features of hereditary site-specific colon cancer (i.e., autosomic dominant model of heredity, absence of associated adenomatous polyposis, prevalence of right-sided colonic lesions, and young age of the patients) is described. The lack of association with solitary adenomatous polyps, the higher survival rate of patients with left-sided colon cancer, and the absence of extracolonic tumors were peculiar characteristics of this family. These data, in agreement with other reports, appear to suggest that the inherited colon cancer syndromes are not a single entity, but a group of related entities linked by their familial occurrence.

Site-specific, simultaneous presentation of colonic carcinoma in identical twins

The development of identically sited carcinoma of the colon in identical twins is described. A simultaneous presentation occurred. The case is discussed in the context of the cancer family syndrome.

Report of a family with cancer family syndrome

A report of the history and management of colonic cancer in two brothers with Cancer Family Syndrome is presented. An analysis is made of the prevalence of colonic and endometrial cancer in this family. The risk to the progeny of affected and unaffected individuals is discussed, and recommendations for screening for early signs of cancer are offered. [Key words: Cancer, colonic, familial; Cancer Family Syndrome.

A linkage study of HLA and inherited adenocarcinoma of the colon

A kindred with the familial cancer syndrome is reported in which every confirmed affected member of the pedigree had at least one primary carcinoma of the colon. The average age at which cancer appeared was 38 years, and multiple primary neoplasm occurred in 23% of the cancer patients. Transmission of the cancer trait is consistent with an autosomal dominant mode of inheritance. Colonoscopy eliminated the presence of any unsuspected cancers in family members at risk. HLA typing was done, and by direct typing or inference, data were available on 66 living and deceased individuals. There were four informative matings in the kindred, the offspring of which showed only three crossovers of a possible 17. The lod score totaled 1.06 at a recombination fraction of 0.20. The need for cooperative efforts of many investigators in HLA linkage studies is emphasized, along with the potential value of such an approach.

Knowledge of colorectal cancer and attitude to occult blood testing among recent medical graduates in New South Wales

The extent to which new information on colorectal cancer (C.C.) is being transmitted to medical undergraduates was assessed in a repeated survey of new interns' knowledge of and attitudes on C.C. A probability sample of 214 graduates of the two Sydney medical schools was drawn as they commenced their internships in 1978. A comparable sample of 186 was drawn in 1980. Interns in each sub-sample completed a questionnaire of 54 pre-coded items of knowledge of C.C. epidemiology, early diagnosis, and followup, and on their attitudes towards C.C. On most topics knowledge was not well developed, and 1980 graduates were not significantly better informed than those of 1978. Almost three-quarters of 1980 interns intend using faecal occult blood testing.

Site-specific colonic carcinoma in identical twins

The development of identically sited carcinomas of the colon in monozygotic twins is described. Presentation occurred with 2 years of each other. They are discussed in the context of the cancer-family syndrome.

An analysis of the age distribution of colon cancer in adenomatosis coli

For the purpose of elucidating the genetic and environmental interaction in human carcinogenesis, the age distribution of colon cancer in adenomatosis coli (AC) patients in Japan and England were investigated and compated. According to the multiple mutation theory of carcinogenesis, the rate of tumor production is presented by a natural logarithm of the reciprocal of the survival fraction (the proportion on diagnosed colon cancer by age t either among AC patients or total colon cancer cases), and thus is given by a power function of t. The number of hits necessary for colon cancer development in AC patients was estimated to be 4.2 or 4.4 for males and 3.4 or 3.3 for females in Japanese cases, whereas it was 4.7 or 3.9 and 3.6 or 3.2, respectively, in English cases. The estimates are compatible between countries. On the other hand, from the age specific prevalence curve, number of hits in general population was estimated to be 5.0 for both sexes in Japan, which is approximately one hit less than the values for English general population, at least in males. The present results, when taking into account the geographic and/or chronologic variations in colon cancer frequency, suggest that the etiology of colon cancer in younger patients is primarily determined by a genetic predisposition whilst environmental factors are much more influential for the development of colon cancer in older patients.

Knowledge and attitudes of gastroenterologists in colorectal cancer

A group of 73 gastroenterological specialists (36 physicians, 25 surgeons, 12 trainees) completed a detailed questionnaire on their knowledge of and attitudes to colorectal cancer. A surprising unawareness of recent developments in colorectal cancer was apparent. Although responses to individual questions varied throughout the three groups, overall knowledge and attitudes on colorectal cancer were not related to age and years since graduation, and were not different in the three groups. This study suggests failure of traditional methods of continuing medical education, and has practical implications for any screening programme designed to detect early colorectal cancer.

Hereditary proximal colonic cancer

Ten families prone to cancer of the colon (in the absence of familial polyposis coli) have been investigated. A significantly greater frequency of carcinomas of the proximal colon was evident relative to non-familial colonic cancers (65% versus less than 35%, P less than .001). Moreover, family members with proximal colonic cancers experienced significantly enhanced survival, compared with family members with distal colonic or rectal cancers. Findings consistent with a genetic predisposition included early mean age at onset (45 years) and a high frequency (40%) of multiple primary cancers in the patients studied. The results are in accord with reported findings in 11 similar kindreds from the literature, and strongly suggest the existence of a heritable variety of colonic cancer in which the proximal colon is at particularly high risk. Extraordinary early diagnostic measures, including colonoscopy, are indicated for members of such families.

Familial occurrence of colon and uterine carcinoma and of lymphoproliferative malignancies: clinical description

Carcinoma of the colon occurred in four generations of a family, including two of three siblings of one generation and eight of 19 members of the next generation. In addition, uterine cancer or lymphoproliferative malignancies were found in two family members. Of 41 members of the fourth generation, two were found to have colon cancer and one had malignant lymphoma. Clinical features were similar to those patients with "cancer family syndrome." Although a precise genetic mechanism is uncertain, it appeared to be transmitted as an autosomal dominant character.

Clinical and roentgen features of the intestinal polyposis syndromes

The intestinal polyposis syndromes represent a challenging diagnostic problem for the radiologist. These syndromes include: familial multiple polyposis, Gardner's, Peutz-Jeghers, Turcot's, Cronkhite-Canada and juvenile polyposis. The polyposis syndromes can usually be differentiated from one another on the basis of the clinical history, examination of the mucocutaneous tissues and roentgen findings. Numerous other conditions, however, may mimmic a polyposis syndrome, and must be considered in the differential diagnosis.

Familial cancer of the gastro-intestinal tract

A family with a high incidence of early onset gastrointestinal carcinoma is described. Individuals from four generations have been proved to have had the disease. The management of individuals as yet unaffected is discussed and a regime for follow-up suggested.

Family studies in cancer of the colon and rectum

Family histories were obtained from 209 patients undergoing treatment for cancer of the colon or rectum at St Mark's Hospital. Death certificates were obtained for parents and siblings who had died. Among these, the number of deaths from cancer of the bowel was more than three times that expected for a comparable group from the general population. There are three principal features which, if present in an index case, are associated with the likelihood that other members of the family will also have had cancer of the large bowel. These are, first, the presence of multiple benign or malignant tumours in the large bowel, secondly, a history of previous primary carcinoma or adenoma of the large bowel and, thirdly, early age of onset of carcinoma of the bowel.

Macrophage electrophoretic mobility (MEM) test in cancer: a critical evaluation

Of 464 patients with verified cancer tested, 463 have been correctly diagnosed by measuring their lymphocyte sensitization to encephalitogenic factor or cancer basic protein. One patient with very rapidly advancing cancer gave a negative result but was found to have marked general hyporeactivity of her lymphocytes of unknown cause. Leukaemia, advanced tuberculosis, asthma, sarcoidosis, systemic lupus erythematosus, and a number of rare conditions may interfere with a correct diagnosis. It is advisable to test guinea-pigs for spontaneous sensitization to encephalitogenic factor and to exclude some of the other conditions by testing for sensitization of the patient's lymphocytes to BSA and PPD.