[Clinical characteristics and efficacy of oropharyngeal carcinoma with secondary primary tumor].

To analysis the clinical features and prognosis in oropharyngeal carcinoma with secondary primary tumor. A retrospective analysis was performed on 468 pathologically confirmed oropharyngeal cancer as the primary tumor patients with p16 status, excluded distant metastasis, and admitted to the Chinese Academy of Medical Sciences from January 2010 to December 2020. The clinical features and prognosis of the secondary primary tumor were analyzed. Among 468 patients with oropharyngeal cancer treated at initial diagnosed, 222 cases were P16-negative. With a median follow-up time of 64.3 months, 66 cases developed second primary cancer, with an incidence of 29.3%, among which 63.6%（42/66） were synchronous and 36.4%（24/66） were heterochronous, esophagus was the most commonly involved site. The 5-year OS of p16-negative oropharyngeal carcinoma with synchronous second primary cancer, without second primary cancer and with heterogeneous second primary cancer were 26.3% and 57.3% and 73.2%（=0.001）; The second primary cancer accounted for 11.2%（12/107） of the deaths in the whole group, among them, the heterochronous second primary accounted for 75.0%（9/12）. There were 246 patients with p16 positive, with a median follow-up time of 52.4 months, 20 patients developed second primary cancer（8.1%）. Among them, 65.0%（13/20） were synchronous and 35.0%（7/20） were heterochronous. Esophagus was the most commonly involved site. The 4-year OS of p16-positive with synchronous, heterochronous and non-second primary cancer group were 51.9%, 80.7% and 83.3%. Secondary primary cancer accounted for 3.8%（2/52） of all deaths in p16 positvie group. The incidence of second primary cancer of p16 positive and negative oropharyngeal carcinoma were different. The esophagus was the most commonly involved site regardless of p16 status. Regardless of p16 status, the survival of patients with synchronous second primary cancer was worse than those without second primary cancer. For p16-negative oropharyngeal carcinoma, the prognosis was better in patients with heterogeneous second primary cancer, the second primary cancer is one of the main causes of death.