Introduction

Purpose

The purpose of this review is to identify the different genomic tests that are being promoted for clinical use in cancer prevention, diagnosis, and management. The project was organized into two distinct parts with separate aims and methodologies:

• The goal of Part I was to answer the key question: What genetic tests are currently available for cancer prevention, diagnosis and treatment?
• The goal of Part II of this project was to answer the key question: What genetic tests are in development for cancer?

The Centers for Medicare & Medicaid Services (CMS) asked the Agency for Healthcare Research and Quality (AHRQ) and the Tufts-New England Medical Center Evidence-based Practice Center to perform a horizon scan of gene-based tests for cancer that are currently in clinical use, are being promoted for clinical use, or are being developed for clinical use. CMS has expressed the need for the deliverable to be a ready reference tool to inform discussions in this area.

Aim

The aim of this horizon scan is to identify the different genomic tests that are being promoted for clinical use in cancer prevention, diagnosis, and management. As outlined in the Detailed Workplan, the project was organized into two distinct parts with separate aims and methodologies. The goal of Part I was to answer the key question: What genetic tests are currently available for cancer prevention, diagnosis and treatment? The goal of Part II of this project was to answer the key question: What genetic tests are in development for cancer?

Definition of a Genetic Test

An essential step early in our project was to establish a definition for genetic test. To this end, we refer to the Secretary's Advisory Committee on Genetic Testing (SACGT)'s broad definition:

A genetic test is an analysis performed on human DNA, RNA, genes, and/or chromosomes to detect heritable or acquired genotypes, mutations, phenotypes, or karyotypes that cause or are likely to cause a specific disease or condition. A genetic test also is the analysis of human proteins and certain metabolites, which are predominantly used to detect heritable or acquired genotypes, mutations, or phenotypes. The purposes of these genetic tests include predicting risks of disease, screening of newborns, directing clinical management, identifying carriers, and establishing prenatal or clinical diagnoses or prognoses in individuals, families, or populations.¹

This definition includes tests for molecular or biochemical biomarkers. It also includes cytogenetic, genomic, genome-based, and gene-based tests. We have found that the terms "genetics" and "genomics" are often used interchangeably in the literature and both can refer to tests for molecular or biochemical biomarkers, as well as cytogenetic and gene-based tests. This review will use the term genetics to also mean genomics.

Clinical applications of genetic tests to be covered by the review. Based on our discussions with AHRQ and feedback from CMS, the following three categories were used to describe the different applications for the various genetic tests:

1. Primary prevention: to detect inherited susceptibility to cancer in persons who do not have cancer, in order to initiate appropriate interventions (prophylactic surgery, drug treatment or intensive and earlier screening).
2. Secondary prevention: early detection of cancer in persons who have early stage (asymptomatic) cancer.
3. Diagnosis and management: includes confirming cancer, classifying cancer, predicting typical course of cancer, choosing type of treatment (e.g., surgery alone or with adjuvant chemotherapy), monitoring response to therapy, choosing the right drug in the right dose at the right frequency (pharmacogenomics).
   1. Diagnostic: test used to confirm or aid in the diagnosis of the particular disease.
   2. Prognostic: information from the test can be used to determine or predict the aggressiveness of the disease or overall outcome of the disease, at the time of initial diagnosis and prior to initiation of treatment. Prognostic information can then be used to determine a particular or individualized treatment plan.
   3. Recurrence: to detect disease recurrence in a patient who has already been diagnosed and treated for cancer. This is a more focused application that could be considered a subset of tests for the above mentioned "diagnosis and management" category.
   4. Monitoring: test used to monitor tumor and/or patient response to treatment.

The focus of this horizon scan was primarily to review the genetic applications used for disease diagnosis, management and recurrence, and secondarily on disease prevention.

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