Hereditary cancer – the evidence for current recommended management

Compliance with professional guidelines with reference to familial cancer services

OBJECTIVE

Professional guidelines define the risk categorisation of patients for a genetic predisposition to cancer based on family history. These guidelines inform the appropriate referral of patients to specialist familial cancer services. Our study aimed to determine the quality of referral letters from general practitioners and specialists to genetic services for breast, ovarian and colorectal cancers, and their compliance with relevant professional guidelines.

METHODS

A retrospective review of the referral letters and patient files of 241 consecutive patients referred between June and October 2008.

RESULTS

Sufficient information to make a risk assessment was provided in 71% of referrals. Of these, 89% were compliant with guidelines. Genetic counsellors collected further information on 167 of the 241 referred patients and of these 83% were appropriate for referral according to guidelines.

CONCLUSIONS AND IMPLICATIONS

Overall, referrals to familial cancer genetic services complied with professional referral guidelines. The majority of referrals were high quality, and with additional information, most patients were shown to be appropriate for review in a familial cancer clinic. Despite this, a better understanding of the reasons for non compliant referrals, and appropriate targeted education and resources is recommended to improve referral quality and compliance.

Clinical outcome and service implications of screening women at increased breast cancer risk from a family history

INTRODUCTION

The value of special screening for women at moderate breast cancer risk with a family history of breast cancer remains controversial. Little is known about recall rates, false negative outcomes and the impact on clinical service. Despite this, surveillance programmes within breast units have been established in the United Kingdom.

PATIENTS AND METHODS

In our institution, screening of women at moderate (lifetime risk, 17-30%) and high risk (>30%) consisted of annual clinical examination and mammography from the age of 35 years. The active study period ran for four months and each patient was followed through a further screening cycle (whole study period), providing information on interval cancers and detection at the subsequent screen.

RESULTS

One thousand one hundred and thirty-two women attended for their incident screen: 137 at high risk, 803 at moderate risk and 192 at standard risk. The median age at cancer diagnosis in the moderate risk group was 54 (range, 45-68) years and the high-risk group 51 (46-52) years, compared to 63 (45-69) years in the standard risk group. Seven cancers were diagnosed during the four-month active study period. Two patients were diagnosed with interval cancers and eight at the next screen, giving a cancer incidence in the whole study period of 17/1132 (1.5%). Thirteen patients had invasive cancer and four had ductal carcinoma in situ (DCIS) The median invasive tumour size was 15 had (range, 7-28)mm and the median DCIS size was 4 (2-30)mm. 10/13 (76.9%) invasive cancers were < or =20mm and 2/13 patients (15.4%) with invasive cancer were lymph node positive. The sensitivity and specificity of mammography were 85.7% and 98.8%, respectively. The mammogram recall rate was 27.6 per 1000. The benign to malignant surgery ratio was 8:17.

CONCLUSION

Screening women at increased breast cancer risk is effective. Early detection and recall rates are comparable to that of older women attending the British National Breast Screening Programme.

BRCA patients and clinical collectives: new configurations of action in cancer genetics practices

Since the late 1980s, in France and in a number of other countries, cancer genetics testing has become a clinical reality, particularly for hereditary breast and ovarian cancer. BRCA tests allowing for the assessment of an increased cancer risk among patients and their healthy relatives are now being routinely performed as part of clinical practice. Based on fieldwork on French clinical cancer genetics and on the French Cancer Genetics Collaborative Network, this paper examines the configuration of entities, actors and activities mobilized by the performance of BRAC testing, and argues that the development of clinical molecular genetic practices is predicated upon the development of new forms of collaborative work that lead to a transformation of the content and organization of medical activities and judgements. The paper analyses three major collective configurations - local multidisciplinary collectives, data collectives and new clinical collectives - and argues that they not only provide the material conditions needed to carry out the relevant activities, but also articulate a series of distinctive bio-clinical interventions. These interventions provide an interface with research activities, produce the epidemiological measurements and tools that are a sine qua non for clinical work in this field, and, most importantly, establish the conventions that underlie practices, which define the criteria that turn tools and novel entities into operational components of clinical settings. It thus appears that in the field of clinical cancer genetics, bioclinical collectives, as a locus of expertise, have replaced the individual judgement of the practicing clinician.

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.

Familial cancer history in patients with carcinoma of the cervix uteri

OBJECTIVES

Several cancers show the tendency to aggregate in families. But the contribution of heredity to the causation of sporadic malignancies, like cervical cancer is unclear.

STUDY DESIGN

Seven hundred and thirty-seven women with operative treated cervical cancer (CX) were searched for familiar history of malignant tumours. Positive familial history was stated, if one first degree relative was affected by malignant tumour. The site of malignant tumour was stated and the mean age was compared.

RESULTS

Twenty-two percent of the women had malignancies at different sites in first degree relatives. In about one-half the mother, in 30% the father and in 11% more than one first degree relative was affected. Overall, first degree relatives of 21 patients (13%) had malignancies of the lungs or the oro-pharynx. Thirty-seven women had malignant tumours of the lower genital tract and 11 had invasive cervical cancer. Mean age of patients with positive familial history was the same as those without (43 versus 42 years) it. But, women whose first degree female relatives had cervical cancer were significantly younger than those with extragenital malignancies (37 versus 45 years). The mean 5-year survival rate was higher in patients with a positive familial cancer history (85.6% versus 74.6%; P=1.7).

CONCLUSIONS

The data suggest, that a small number of patients have a familial susceptibility for cervical cancer and probably for HPV-associated neoplasms. Further studies establishing the immune status and the search for genetic polymorphisms of these patients are required.

Family history of cancer, oral contraceptive use, and ovarian cancer risk

OBJECTIVE

The purpose of this study was to determine whether women with a family history of ovarian cancer are at reduced risk of ovarian cancer from the use of oral contraceptives and to compare their risk with that of women with no family history of ovarian cancer.

STUDY DESIGN

A population-based case-controlled study was conducted from May 1994 through July 1998 in which 767 women aged 20 to 69 years with a diagnosis of epithelial ovarian cancer were ascertained from 39 hospitals in 3 northeastern states. Personal interviews with the women and 1367 control subjects provided data that allowed us to estimate the relative risk of ovarian cancer in relation to a family history of cancer and total duration of oral contraception.

RESULTS

Among the 33 case patients and 24 control subjects with a first-degree family history of ovarian cancer, risk of ovarian cancer declined with increasing duration of oral contraception (P =.01). Risk reduction from short-term use of oral contraceptives (< or = 48 months) did not differ significantly by family history (combined estimate of odds ratio, 0.72; 90% CI, 0.59%-0.87%). Risk reduction from long-term use of oral contraceptives (>48 months) was greater in women with a positive family history of ovarian cancer (odds ratio, 0.12) than in women with a negative family history of ovarian cancer (odds ratio, 0.51; test of interaction, P =.04; 692 case patients, 1279 control subjects).

CONCLUSION

Four to 8 years of oral contraception may substantially reduce the risk of ovarian cancer by age 70 years in women with a family history of the disease, from approximately 4 women per 100 women who did not use oral contraceptives to only 2 women per 100 women who did use oral contraceptives.

Is informed choice in genetic testing a different breed of informed decision-making? A discussion paper

Traditionally genetic counselling has promoted a non-directive approach to patients' decision-making but the feasibility of this has been questioned. Unlike most branches of medicine, which are shifting away from a paternalistic model, genetic counselling is approaching shared decision-making from a different perspective. There are certain features of genetic counselling and genetic testing which may complicate the drive towards shared decision-making and informed choice: 1. Genetic test results can have broader implications than non-genetic test results. 2. Genetic test results may be perceived by the patient differently to non-genetic test results. 3. Carrier status for autosomal recessive conditions may be difficult for patients to conceptualize. 4. Decisions in genetic counselling are often multiple and sequential. 5. Most information in genetic counselling is based on probabilities and uncertainties. Each of these features is discussed in relation to achieving shared decision-making in genetic testing and the implications for genetic counsellors are described. The points raised, however, have broader implications for medicine as several of the features, although central to genetic testing, are not entirely unique. Lessons learnt from genetic testing and genetic counselling in achieving shared decision-making could help develop methods of promoting informed choice in other medical arenas such as cancer screening.

DNA technology, the clinical laboratory, and the future

OBJECTIVE

To review the advances in clinically useful molecular biological techniques and their applications in clinical practice as presented at the Ninth Annual William Beaumont Hospital DNA Symposium.

DATA SOURCES

The 10 manuscripts submitted were reviewed and their major findings were compared with literature on the same topic.

STUDY SELECTION

One manuscript reviewed the development of pharmacogenetics, 3 described analytic approaches to detect aneuploidy or cancer, 1 described transcription factor E2F-1 increase during apoptosis, 2 reported on genetic and pharmacologic factors that influence platelet aggregation, 2 described molecular methods for detecting long QT syndrome or mycobacteria, and 1 reported a modification in collection of buccal DNA.

DATA SYNTHESIS

Genomic and proteomic approaches to develop clinically useful assays have been successful. Aneuploidy can be easily detected by comparative genomic hybridization, which does not require cell culture like cytogenetics. Mutations have been characterized for a variety of hereditary cancer syndromes, 2 inherited long QT syndromes, and thromboembolism. PlA1 and PlA2 polymorphisms in platelets are associated with a difference in aggregation inhibition by estrogen, another example of genotypic pharmacogenetics. Protein expression differences may define colorectal cancer stage and explain apoptotic signal transduction. Mycobacterial detection by nucleic acid amplification and simplified buccal DNA collection demonstrate cost-effective strategies.

CONCLUSION

The working draft of the Human Genome Project is completed and the number of clinically useful molecular pathologic techniques and assays will expand as additional disease-associated mutations are defined. Expanded use of database software for genomic and proteomic screening should increase the efficiency of clinical useful assay development.