Four Cancer Chemoprevention Trials Seek Subjects

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

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

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

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

More than 1,000 patients will be randomized to receive either30 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 premalignantlesions of the oral cavity, cervix, and skin, Dr. Donahue noted,and to prevent second primary tumors in head, neck, and lung cancerpatients. This trial will assess the qualitative and quantitativetoxicity of daily use.

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

All women older than age 60 and women older than age 35 with otherrisk factors are eligible to enroll. Risk factors considered includenumber of first degree relatives who had breast cancer, nulliparityor age at first live birth, number of benign biopsies of the breast,and presence of atypical hyperplasia or lobular carcinoma in situon a prior biopsy. Women with a history of invasive breast canceror DCIS are being excluded.

The study group will be stratified by risk and randomized to receiveeither 20 mg of tamoxifen or placebo daily for 5 years. Subgroupswill be studied to evaluate the drug's effects on bone density,blood lipids, and serum cholesterol, to corroborate previous reportsof estrogen-like effects in postmenopausal women.

Colorectal Adenoma Trial

The Colorectal Adenoma Prevention Trial will evaluate whetheraspirin can decrease the number of recurrent ade-nomas and prolongdisease-free survival in patients who have undergone curativeresections for histologically documented cancers.

The trial is enlisting patients treated for Duke's stage A orB1 tumors and 5-year disease-free survivors of stage B2 or C cancers;all patients must have had colonoscopy in the past 4 months withremoval of all visible polyps.

Pregnant and nursing women; individuals with a history of inflammatorybowel disease, familial polyposis, or active invasive malignancy;and those with severe heart disease, abnormal hemoglobin levels,or contraindications to aspirin use are being excluded.

The 900 men and women enrolled will be randomized to receive either325 mg of enteric-coated aspirin or placebo daily for 3 years.All participants will undergo colonoscopy at the end of the trial.The number of neoplastic polyps, time of occurrence, morbidity,and mortality will be recorded.

The Prostate Cancer Prevention Trial is designed to determinewhether finasteride (Proscar), which blocks 5 alpha-reductaseactivity to lower dihydro-testosterone levels, can prevent prostatecancer or slow the progression of early tumors to life-threateningstages.

It will enroll 18,000 healthy men 55 years of age or older inas close to a representative sample as possible of the racialand ethnic distribution of the disease, which exacts the highestmortality among African-American men.

Participants will receive digital rectal examinations and haveprostate-specific antigen (PSA) levels measured; then they willbe randomized to receive either 5 mg of finasteride or placebodaily for 7 years. At the end of the trial, all of the men willundergo prostate biopsy.

The trial and control groups will be compared in terms of stageand grade of prostate cancer, incidence and severity of benignprostate hyperplasia, number of deaths from prostate cancer, andoverall mortality. This trial is expected to close to new accrualson December 1, 1996.

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For More Information

For more information about these and other current clinical trials,physicians can telephone the NCI's cancer information hotlineat 1-800-4-CANCER or access the NCI's cancer information databasewith a PDQ access code. The Don Monti Cancer Center in Manhasset,NY also offers information about these trials through its ownhotline, at 516-562-8255.