SAN FRANCISCOThe drug anethole dithiolethione (ADT)normally used for
dry mouth and marketed as Sialor or Sulfarlemreduced the risk of new or
worsening dysplastic lesions in the lungs of current and former smokers by 22%,
compared with placebo, according to a study presented at a late-breaking
research session of the 93rd Annual Meeting of the American Association for
Cancer Research (abstract LB-119).
"This study shows that ADT has promise and may halt or slow the
development of cancer," said Stephen Lam, MD, professor of medicine, and
chair, Lung and Tumor Section, University of British Columbia.
He noted that 50% of lung cancer patients are former smokers and that even
with the best smoking cessation programs, over 70% of smokers need to try
quitting more than once before they succeed. "Both of these factors are
why we are looking for a lung cancer chemopreventive agent," he said.
In the 6-month study, 101 current and former smokers with bronchial
dysplasia were randomly assigned to receive 25 mg of ADT orally three times a
day or a placebo. To qualify for the study, patients had to have smoked a pack
a day for 30 years or two packs a day for 15 years. All patients had bronchial
dysplasia identified by autofluorescence bronchoscopy-directed biopsies.
Risk of Progression
The risk of progression from dysplasia to cancer varies from 2% to 40%
within 10 years, depending on the grade of the dysplasia, Dr. Lam said.
After completing their treatment, all patients had a repeat bronchoscopy and
biopsy of the same sites, plus any new areas that looked suspicious for
dysplasias. Changes in the histopathology grade of the biopsies were used as
the primary endpoint biomarker.