Cancer occurrence in old age: Results of a population-based cancer registry in Semnan, Iran.

INTRODUCTION: The proportion of elderly persons has increased in most countries during the last few decades, and will increase further in the coming years. A population-based study was here carried out to clarify the site-specific cancer-incidence rates in old age in Iran. AIMS AND METHODS: A comprehensive search was undertaken to survey and register all new cancer cases during a 5-year (1998-2002) period among the indigenous population of Semnan Province aged 65 years or over. Diagnosis of cancer was based on histopathology, clinical or radiological findings, and death certificates. RESULTS: A total of 791 patients were registered with cancers. Of these, 492 (62.1%) were males. Crude rates were 1,310 and 962 per 100,000 persons per year for males and females respectively, and age-standardized ratios (ASRs) were 1350 and 973. Gastric cancer was the most common tumor with incidence rates of 340 and 153 per 100,000 persons per year for elderly males and females respectively. In women breast cancer was the second most common cancer (ASR= 108). In men prostate cancer was the second most common cancer with ASR= 150. CONCLUSIONS: Based on the present standardized rates, cancer is almost 9 times and 7 times more frequent among the elderly compared with younger men and women (30-64). The highest incidence of cancers was in group 75-79 years in both sex and then decrease was noted with increasing age.