Population Screening for Inherited Cancer-Related Gene Mutations

Treating IEN, Not Chemoprevention

News from the War on Cancer

Virtual Colonoscopy...At the Forefront of Colorectal Cancer Screening

Virtual Colonoscopy...Is Not Yet an Acceptable Option for Colorectal Cancer Screening

Cancer Prevention Working Group Convenes to Discuss Speeding Cancer Prevention Agents to Patients

Cancer Prevention Clinical Trials

Cancer Prevention Legislation(State)

Cancer Prevention Legislation(Federal)

David S. Alberts, MD
Director, Cancer Prevention and Control
Arizona Cancer Center
University of Arizona
Tuscon, Arizona

Isn't it time that we end the artificial separation of cancer prevention and cancer treatment research efforts within cancer centers? By maintaining this false separation, there is loss of intelligent thought, unnecessary duplication of effort and degradation of cancer research team spirit. As we continue to realize that there is a continuum for cancer treatment opportunity from the first initiated cell through mild, moderate and severe dysplasia, carcinoma in situ, invasive cancer and metastatic cancer, the fields of cancer chemoprevention and cancer chemotherapy may become indistinguishable(1).

In fact, the recent, American Association for Cancer Research’s Task Force on Intraepithelial Neoplasia (IEN) concluded that there is an IEN for virtually every solid tumor and that treatment of these IENs can result in long-term reduction in cancer risk(2). Two instructive examples of this concept are the Food and Drug Administration's (FDA) approvals of tamoxifen and celecoxib for patients at risk for breast and colon cancers, respectively(3,4). In the former example, a standard drug (i.e., tamoxifen) used in the treatment of advanced breast cancer proved effective in the treatment of breast IEN (e.g., ductal carcinoma in situ), whereas in the latter example, a molecularly targeted agent (i.e., celecoxib, a selective inhibitor of COX-2) effectively reduced colorectal adenoma number, and now is being studied in the context of treatment of advanced, metastatic solid tumors.

Should we continue to describe the treatment of IEN as chemoprevention?
In reality, chemoprevention is neither chemotherapy nor prevention. With respect to the use of tamoxifen and celecoxib in the "treatment" of IENs in the breast and colorectum, respectively, neither of these drugs can be categorized as a chemotherapeutic agent and reduction of cancer risk is a more accurate and realistic term than is cancer prevention (i.e., in neither FDA New Drug Approval trial for these two agents was evidence presented of ultimate cancer prevention). "Cancer delay" is a term coined by Dr. Scott Lippman and Dr. Waun Ki Hong of the MD Anderson Cancer Center related to their studies of retinoids to "treat" IENs in the upper aerodigestive tract(5). Through their temporary suppression effects, drugs may delay the potential onset of cancer; however, I prefer instead the concept of reducing cancer risk (since the delay may be permanent).

With the increasing focus on IEN for both screening/detection and treatment, the field of cancer prevention research is moving into the mainstream of clinical oncology. In fact, as shown in Figure I, there are innumerable opportunities to intervene therapeutically along the entire carcinogenesis pathway. Cytostatic agents such as tamoxifen and celecoxib will be employed by clinical oncologists to treat IENs as well as to treat early and late stage invasive cancers. It is time to activate a new vocabulary that more clearly describes our efforts to "treat" all aspects of carcinogenesis.