Clinical Outcomes and Prognostic Factors in Multiple Primary Malignancies Involving Oral Cancer

Background : The incidence of multiple primary oral cancers (MPOCs) is rising, presenting significant diagnostic and treatment challenges and often resulting in poor prognosis. However, most research focuses on cases where all primary tumors originate within the oral cavity, with limited attention to scenarios where oral cancer arises as a second primary after initial tumors in other parts of the body. This study examines the clinical characteristics and prognosis in both scenarios. Methods : A retrospective review of 165 patients at the Affiliated Stomatological Hospital of Sun Yat-sen University identified 75 oral cancer first (OCF) cases and 90 non-oral cancer first (N-OCF) cases. We conducted a comparative analysis of clinical characteristics and prognosis between the two groups. Results : MPOCs were more common in males, with an average age of 59.4 years, primarily presenting as early-stage squamous cell carcinoma (SCC), with the tongue as the most frequent site for secondary primary cancer (SPC). In the OCF group, the most common site for the first primary cancers (FPC) was also the tongue, whereas in the N-OCF group, it was the nasopharynx. Survival rates were comparable between the two groups, with key prognostic factors including age(p=0.015), SPC T stage(p=0.003), cervical lymph node metastasis of SPC(p=0.021), and recurrence after SPC(p=0.020). Conclusions : Patients with a history of nasopharyngeal cancer require long-term oral follow-up. While the location of FPC and SPC does not impact prognosis, early diagnosis and treatment significantly improve outcomes by enabling timely intervention before tumors advance or metastasize. Effective management of OPMDs is crucial for improving outcomes in MPOCs patients.