Early findings from a community-based, cluster-randomized, controlled oralcancer screening trial in Kerala, India

BACKGROUND. Oral cancer satisfies the criteria for a suitable disease for s creening, and oral visual inspection is a suitable test for oral cancer scr eening. The efficacy of screening in reducing mortality from oral cancer ha s nor yet been evaluated. The authors describe a cluster-randomized, contro lled oral cancer screening trial in southern India and its early results. METHODS. Apparently healthy subjects age 35 years or older in 13 clusters c alled panchayaths were randomized to either an intervention group (n = 7) o r a control group (n = 6). Subjects in the intervention group will receive 3 rounds of screening consisting of oral visual inspection by trained healt h workers at 3-year intervals. The first round of screening was carried out between October 1995 and May 1998. Participants were visited in their home s and interviewed for sociodemographic derails, tobacco-smoking and alcohol -drinking habits, and personal medical history. Those with tobacco or alcoh ol habits were advised to stop those habits. Subjects in the intervention g roup were offered screening, and those with lesions suggestive of oral leuk oplakia, submucous fibrosis, or oral cancer were referred for examination b y physicians. Confirmed leukoplakias were excised whenever possible, others were kept on follow-up, and those with confirmed oral cancers were referre d for treatment. Data on oral cancer incidence, stage distribution survival , and mortality in rile study groups are obtained by record linkage with th e Trivandrum population-based cancer registry and municipal death registrat ion systems. RESULTS. There were 59,894 eligible subjects in the intervention group and 54,707 in the control group; 31.4% of the former group reported no tobacco or alcohol habits, compared with 44.1% of the latter. The distribution of a ge, education, occupation, income, and socioeconomic status were similar in the two groups. Of 3585 subjects in the intervention group referred, 52.4% were examined by physicians; 36 subjects with oral cancers and 1310 with o ral precancers were diagnosed. Of the 63 oral cancers recorded in the cance r registry, 47 were in the intervention group and 16 were in the control gr oup, yielding incidence rates of 56.1 and 20.3 per 100,000 person-years in the intervention and control groups, respectively. The program sensitivity for detection of oral cancer was 76.6% and the specificity 76.2%; the posit ive predictive value was 1.0% for oral cancer. In the intervention group, 7 2.3% of the cases were in Stages I-II, as opposed to 12.5% in the control g roup. The 3-year case fatality rates were 14.9% (7 of 47 patients) in the i ntervention group and 56.3% (9 of 16 patients) in the control group. CONCLUSIONS. Though compliance with referral for confirmatory examination i n the first round was lower than the 70% anticipated, intermediate end poin ts, such as stage at diagnosis and case fatality, indicate that the trial i s making fairly satisfactory progress. (C) 2000 American Cancer Society.