Oncology Community Must Guide Public on Gene Testing Nuances

OncologyLive, December 2010, Volume 11, Issue 12

The genuine revolution in our understanding of the genetic basis of malignant disease has led to a corresponding interest in defining the risk of developing a particular disease for both individuals and specific populations.

The genuine revolution in our understanding of the genetic basis of malignant disease has led to a corresponding interest in defining the risk of developing a particular disease for both individuals and specific populations.

Consider, for example, the reactions to genetic testing for breast and ovarian cancers. An extensive body of epidemiologic research has revealed that women known to possess a BRCA1 or BRCA2 germ-line mutation have a substantially increased lifetime risk for the development of breast or ovarian cancer, or both of these malignancies. Existing data indicate that individuals who gain specific knowledge of the presence of these mutations favor interventions that may substantially reduce their risk for the development of these cancers.

Unfortunately, a truly major limitation of genetic testing has been the modest ability of such tests to unequivocally document with reproducible results that a particular abnormality predicts a stated risk of cancer (if a claimed risk is examined in a population independent from that of the original study set), or even that the abnormality is itself reproducible if the testing is repeated by a second laboratory involving the initial patient population. Thus, while it is reasonable to discuss the impressive promise of genetic testing to define cancer risk (or the risk of other serious medical conditions), one must strongly emphasize that this complex and still often poorly understood research effort remains a true work in progress.

Despite such serious concerns, the era of genomic data being directly available to the requesting consumer is unquestionably upon us. 1-3 First, there has been a rather dramatic reduction in the cost associated with obtaining such analyses, and this striking trend is anticipated to continue in the future. In fact, it is reasonable to anticipate that in the very near future it will not be uncommon for an individual or an entire family to simply write a check or pay online and be provided a detailed analysis of their “personal genome.”

Second, the public has been rather extensively exposed to reports about various claims of genetic associations with a number of serious medical conditions. Despite the tremendous uncertainties associated with such research, it is understandable that individuals might want to be provided the information regarding the presence or absence of specific abnormalities or features in their genes and then make their own decisions regarding how such data should be interpreted. Such a conclusion may be particularly relevant for individuals with a perceived “high cancer risk,” based on knowledge of their own family history (eg, 3 siblings within a single family with a history of cancer at a young age).

With such trends converging, it is virtually certain we will soon be witness to the widespread availability of detailed individual genetic maps—completely independent of any confirmation of fundamental scientific validity.

This is not to suggest, however, that the scientific and medical community will be unable to influence the future course of events in this arena. In fact, our community should play a major role in providing accurate, understandable, and up-to-date information to our patients and the general public about levels of evidence regarding associations between specific genetic data and various diseases or medical conditions. A particularly important component of such educational efforts should be a focus on the validity of interventions suggested or claimed to favorably modify stated risks (ie, major changes in lifestyle or prophylactic surgery).

It is unquestionably clear that an optimal cost- effective communication strategy for the provision of timely information to as large an audience as possible will make extensive use of the Internet through such tools as educational videos on demand and interactive general community or patient/disease-specific forums. Considering the certainty that many people will be seeking guidance from medical professionals about personal genetic data of unclear or completely unknown clinical relevance, there is a genuine urgency to begin discussions regarding how we might effectively undertake such communications.