In 1990, the five leading causes of cancer death in men aged 65 and ol
der were carcinomas of the lung, prostate, colon and rectum, and pancr
eas, and leukemia. For women in this age group, the five leading cause
s of cancer death were carcinomas of the lung, breast, colon and rectu
m, pancreas, and ovary. To determine the representation of the elderly
in clinical trials, the 1992 accrual of the National Cancer Institute
(NCI)-sponsored Clinical Cooperative Group treatment trials (which in
cluded more than 8000 elderly patients) for the aforementioned sites w
as compared with the 1990 incidence data from the NCI's Surveillance,
Epidemiology, and End Results program. Of the male patients enrolled i
n the trials, an average of 39% were older than 65 (47.3% lung, 79.5%
prostate, 47.5% colorectal, 45.6% pancreas, and 9.6% leukemia); wherea
s 25.9% of all women enrolled in trials were 65 or older (43.6% lung,
17.3% breast, 46.2% colorectal, 59.6% pancreas, and 35.4% ovary). With
respect to incidence, older patients generally are underrepresented i
n cancer treatment trials. With the exception of the data on prostate
cancer, each of the comparisons using the Z statistic gave probability
values of less than 0.01. The most significant discrepancies between
incidence and participation in cancer treatment protocols were noted f
or leukemia in males and breast cancer in females. Possible explanatio
ns for these findings include (1) a research focus on aggressive thera
py, which may be unacceptably toxic to the elderly; (2) presence of co
morbidity in the elderly; (3) fewer trials available specifically aime
d at older patients; (4) limited expectations for long term benefits o
n the part of physicians, relatives, and the patients themselves; and
(5) a lack of financial, logistic, and social support for the particip
ation of elderly patients in clinical trials. Recognizing this situati
on, NCI recently sponsored a number of trials that specifically target
the elderly. This paper describes the status of all major Phase II an
d III clinical trials that recently were closed, still are active, or
now are in review that address the clinical care of this important seg
ment of the U.S. population.