The incidence of other primary tumours in patients with oral cancer in Scotland.
Crosher R. McIlroy R.
Department of Maxillofacial Surgery, City Hospital, Edinburgh, Scotland, UK.
OBJECTIVE: To find out the incidence of second or multiple primary malignant tumours in patients with oral cancer in Scotland and identify the sites at most risk. DESIGN: Retrospective cohort study of data from the Cancer Registry. SUBJECTS: 1891 patients registered with oral cancer in Scotland between 1 January 1980 and 31 December 1986. MAIN OUTCOME MEASURES: Relative risks of subsequent cancers in patients with oral cancer. Identification of the sites at most risk of second cancers. RESULTS: Of the 1891 patients, 228 (12%) developed a second primary cancer. The mean follow-up period was 3.2 years. Fourteen patients had 3, and 2 patients had 4 primary cancers. The overall risk of second primary cancers was 2.03 (95% confidence intervals (CI) 1.77 to 2.39) times greater than expected in the general population. The relative risk for male patients was 1.95 (95% CI 1.65 to 2.24) and for female patients 2.29 (95% CI 1.7 to 2.9). CONCLUSIONS: Men with cancer of the lip in Scotland have an increased risk of developing second cancers of the lip and skin (excluding melanoma), whilst women with cancer of the lip have an increased risk of developing skin cancer only. Both men and women with intra-oral cancers have increased risks of developing second cancers of the oral cavity, pharynx, and trachea, bronchus, and lung, while men alone have an increased risk of developing second cancers in the oesophagus.