A series of patients with oral squamous cell carcinoma (SCC) observed at th
e "Regina Elena" Cancer Institute was retrospectively reviewed in order to
analyse the risk factors for multiple and second primary tumours (SPTs), th
eir impact on survival and effective measures to control this phenomenon. I
n a survey of 200 individuals with a median follow-up of 3.2 years (25th pe
rcentile: 1.2, 75th percentile: 5.5), the incidence rate of SPTs was 14%: 3
9% arose in the oral cavity, 18% in the oropharynx, 10% in the lung and 7%
both in the lip and larynx. There were no cases of secondary oesophageal tu
mours. Ninty-six per cent of the diagnosed histological types of SPTs were
SCCs. Forty per cent of the new cancers were synchronous and 60% were metac
hronous, developing at a steady rate of 1.5% per year with no evidence of p
lateau. The overall incidence, adjusted by the length of follow-up, was 40
SPTs per 1000 person-years of follow-up. Although all the patients were at
a greater risk for SPTs, the rates widely varied, according to specific fac
tors: heavy tobacco consumption accounted for a statistically significant r
isk excess which was particularly high among younger smokers with an index
tumour of the lower oral cavity. No difference was noticed in relation to t
he index neoplasm stage. In patients both with localised and advanced index
tumours, 5-year survival rates were lower in those with SPTs and the diffe
rence was statistically significant for the a-year survivors who were most
likely to overcome the first disease. The present study confirms the except
ionally high incidence of multifocal SCC in oral cancer patients and emphas
izes the importance of preventive measures, since careful screening procedu
res, carried out to detect multifocal tumours at an early stage, should imp
rove survival in these patients. (C) 1999 Elsevier Science Ltd. All rights
reserved.