Multiple primary squamous cell carcinomas of the oral cavity

There is a subset of patients who develop multiple primary squamous cell carcinomas (SCCs) of the oral cavity. The aim of this study was to better characterize this group of patients and determine whether there are any associated risk factors.

This is a retrospective review of all patients treated for oral SCCs at the University of Maryland Department of Oral and Maxillofacial Surgery from November 1989 to February 2013. The inclusion criteria were patients who developed at least 3 primary oral cancers. Lesions were considered separate primaries if they involved different anatomic regions within the oral cavity and were more than 2 cm apart or if they occurred more than 5 years apart.

Of 1,478 patients treated during this time frame, 20 met the inclusion criteria. There were 14 women and 6 men (female-to-male ratio, 2.3:1). Nineteen were Caucasian and 1 was of Indian ethnicity. The average number of primaries per patient was 3.9 (range, 3 to 6 primaries). The mean age at first diagnosis was 63.3 years (44 to 86 yr). The mean interval between the different primaries was 32 months (0 to 228 months). The most common site involved was the gingiva (45% of cases), followed by the tongue, buccal mucosa, retromolar fossa, and soft or hard palate. The mean follow-up was 118 months (22 to 342 months). Eleven patients developed nodal disease. Of those 11 patients, 9 died of the disease (<20% survival). The average time to neck involvement was 66.4 months. The average time from last neck involvement to death was 11.5 months. More than half the patients were nonsmokers or had quit more than 10 years before the first diagnosis. All patients quit smoking during the course of their treatment yet continued to develop multiple primaries. Three patients had proliferative verrucous leukoplakia (PVL), and 4 patients had biopsy-proved lichen planus.

The incidence of multiple primary SCCs within the oral cavity appears to more commonly involve Caucasian women without risk factors, although lichen planus and PVL might play a role. The gingiva appears to be the most commonly involved primary site, and subsequent primaries tend to be restricted to the oral cavity. Close observation and early expectant treatment appear to improve prognosis and survival in these patients. Cervical nodal metastases adversely affected survival (P = .02) as did the development of more than 4 primary carcinomas (P = .04).