Approach to Patients with Suspected HNPCC

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The most important component of the management of HNPCC is identifying the affected individuals and their families. HNPCC has been defined by the Amsterdam Criteria: 3 affected individuals on the same side of the family; 2 successive generations; 1 affected individual who is a first-degree relative of the other 2; and colorectal cancer diagnosed before age 50 years (Vasen et al, 1991). These criteria were established to identify high-risk families for genetic studies in an attempt to identify the genes causing the syndrome. Some HNPCC families do not meet the Amsterdam Criteria. Because the original Amsterdam Criteria did not include extracolonic malignancies, the criteria were modified to include endometrial cancer, renal pelvis and ureter transitional cell carcinoma, and small bowel ade-nocarcinoma. The Amsterdam II Criteria (Vasen et al, 1999) include any combination of the latter 3 extracolonic malignancies as well as colorectal cancer that affects 3 individuals in a family and 2 successive generations, with 1 of the individuals diagnosed before the age of 50 years and with the affected individual a first-degree relative of the other 2. Other criteria have been reported in an attempt to identify at-risk and affected individuals, but the most important aspect in identifying a potential HNPCC patient is the suspicion that the individual could be affected, with suspicion based on the clinical history, family history, age at diagnosis, or histopathologic characteristics of the tumor.

Discussion of Therapeutic Options

Once a patient is identified as a potential HNPCC patient, the most important aspect of care is the multidisciplinary approach. This is emphasized in our Gastrointestinal Center at M. D. Anderson Cancer Center. During the first visit of a patient to our Gastrointestinal Center, a complete history and physical examination are performed, including a detailed family history. During this visit, the therapeutic options for the specific condition are discussed with the patient. In addition, the clinician gives a general overview of HNPCC and answers any questions that the patient has.

Genetic Counseling, Genetic Testing, and Communication of Results

Once the therapeutic decisions have been made, a genetic counseling session is arranged. This session is usually scheduled for after the patient has recovered from surgery; however, for patients who have already had surgery, the meeting is arranged at the patient's convenience. The genetic counseling session is a multidisciplinary session and generally is led by one of our genetic counselors. However, a clinician with special interest in HNPCC is always available to answer any questions regarding treatment. For some individuals, the first genetic-counseling session is relatively straightforward because they already have an idea that there is a problem within the family. For others, 1 session may not suffice for the patient to understand the implications of potentially being a member of a kindred with HNPCC. During this visit, the patient is given a more extensive overview of the syndrome, including genetics, inheritance patterns, manifestations, and genetic testing. Ample time is allowed for the patient to ask questions.

Next comes the question of how to confirm a suspected diagnosis. One of the crucial aspects of genetic testing is deciding what is to be done with the information obtained. Are there benefits for those affected individuals and their families? What are the downsides to knowing the mutation status? What if a mutation is not identified? Our genetic counselors discuss all these aspects with the patient in subsequent counseling sessions. Most patients require more than 1 visit to have their questions addressed. It is important to emphasize to patients that genetic testing is not simple and can have major implications throughout the patient's lifetime.

Once all questions are answered, patients are asked whether they want to proceed with genetic testing. If the answer is affirmative, written informed consent is obtained and then a blood sample is collected. Genetic testing is performed in a Clinical Laboratory Improvement Amendment-certified laboratory. Results are given to patients in person, although some individuals are not immediately ready to get the results and choose to delay their appointment. Again, the genetic counselor and physician are available for any questions after the results are given. In case the need for psychological support arises, our team includes a qualified psychologist who is available for intervention. The clinical implications of the results are discussed with the patient.

It cannot be overemphasized that ample time should be given to genetic counseling prior to genetic testing. A detailed discussion of the potential implications of both a positive and a negative test result should be undertaken. If a number of family members are to be tested, the discussions can be held both privately and for the family as a group. However, we give the results of the testing in private. The patients are contacted 1 and 6 months after the test so that we can answer any questions they may have as well as to give follow-up.

An important aspect of genetic counseling is choosing whom to test. As discussed earlier, several criteria help both the clinicians and the genetic counselors in selecting the individuals who most likely will be members of HNPCC kindreds. Nevertheless, any individual who undergoes genetic testing with negative findings for a mutation must understand that if he or she is the first individual to be tested in the family, a negative test result is not informative. If HNPCC is strongly suspected, surveillance for that individual and at-risk family members should be consistent with the surveillance criteria of the International Collaborative Group on HNPCC (Table 8-1). A negative mutation result will be informative for individuals who are at risk and have a mutation identified in their families. Such

Table 8-1. International Collaborative Group on HNPCC Guidelines for

Screening of Genetic Carriers or At-Risk Individuals

Table 8-1. International Collaborative Group on HNPCC Guidelines for

Screening of Genetic Carriers or At-Risk Individuals

Site at Risk

Procedure

Age to Start, years

Frequency

Colon

Colonoscopy

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