MANHASSET, NY--High-risk individuals are being enrolled in four
multicenter clinical trials aimed at preventing lung, breast,
colorectal and prostate cancers. These cancers together account
for more than half of all cancer deaths, Laura Donahue, MD, said
as she recruited participants at North Shore University Hospital's
Don Monti Cancer Center Screening and Education Day.

The National Cancer Institute (NCI) is funding these double-blind,
placebo-controlled prospective trials, which will be conducted
in collaboration with hundreds of hospitals and medical centers
in the United States and Canada.

Patients who had stage I non-small-cell lung cancer with no more
than one primary tumor at a time are eligible to enter the Lung
Cancer Prevention Trial if they underwent complete surgical resection
within the past 3 years and are no longer receiving cancer therapy.

"Despite the early stage of diagnosis, 5-year survival is
still poor in this population, ranging between 50% and 60%, Dr.
Donahue said. Moreover, she added, in long-term survivors of the
initial surgery, the incidence of second primary tumors can range
up to 12%.

More than 1,000 patients will be randomized to receive either
30 mg of 13-cis-retinoic acid or a placebo daily for 3 years,
with 4-year follow-up.

Retinoids have been shown to halt the progress of premalignant
lesions of the oral cavity, cervix, and skin, Dr. Donahue noted,
and to prevent second primary tumors in head, neck, and lung cancer
patients. This trial will assess the qualitative and quantitative
toxicity of daily use.

The Breast Cancer Prevention Trial will examine whether tamoxifen
(Nol-vadex) can reduce the incidence of and mortality from breast
cancer in 13,000 healthy women considered at high risk, based
on an NCI model. This study was undertaken because tamoxifen has
proven effective in preventing recurrent disease in breast cancer
patients.