SAN FRANCISCODrug therapies aimed at reducing or eradicating
intraepithelial neoplasia (IEN) could reduce the burden of IEN and the
incidence of malignancies, according to the American Association for Cancer
Research (AACR) Task Force on the Treatment and Prevention of Intraepithelial
Neoplasia. Three of the co-chairs of this Task Force reviewed key
recommendations at a news briefing at the 93rd Annual Meeting of the AACR.
The IEN Task Force recommended the initiation of clinical trials to evaluate
the usefulness of treating IEN only in high-risk populations. Individuals with,
for example, severe Barrett’s esophagus, high-grade prostatic intraepithelial
neoplasia, and women with abnormal breast cells who have been previously
treated for breast cancer or who have a family history of breast cancer would
be considered to be at high risk.
"The earlier you intervene, the more likely it is that you’ll have a
good result. As cancer becomes invasive, it becomes increasingly resistant to
treatment," noted Gary Kelloff, MD, a senior scientist in the National
Cancer Institute’s Division of Cancer Treatment and Diagnosis.
Therapeutic Interventions Limited
Therapeutic interventions for IEN are limited, however. With only a few
exceptions, IEN is currently treated with surgery, with its attendant risks and
limitations. "Surgery gets only one focal lesion at a time, and often you
have many lesions present, such as a damaged epithelium that has been insulted
with cigarette smoke for 20 years," Dr. Kelloff said.
Disfigurement is another disadvantage associated with certain surgeries,
such as mastectomies. Drug therapies for treating IEN would not have these
disadvantages. Currently, however, there are only about five drugs on the
market for treating intraepithelial neoplasia. "Why do we have so
few?" asked Joyce O’Shaughnessy, co-director of breast cancer research,
Baylor-Sammons Cancer Center, US Oncology, Dallas. "It’s because it
takes over a decade, $50 to $100 million, and many thousands of patients to do
a clinical trial to prove the effectiveness of a cancer prevention drug if you
have to wait for the cancers to develop."
The major finding of the Task Force, she said, is that "we don’t have
to wait for cancer to occur to prove that a drug is beneficial."