Title: Second Primary Tumors in Patients With Nasopharingeal Cancer Treated by Radiotherapy
Abstract: Second primary tumors have a substantial impact on survival in cancer patients. However, real incidence has not been documented well, especially in nasopharyngeal carcinoma (NPC). The aim of this retrospective study was to evaluate the risk of development of second primary tumor in patients with nasopharyngeal cancer treated with radiotherapy or radiochemotherapy. Two hundred fifty two consecutive patients with pathologically confirmed, nonmetastatic, NPC who received radiotherapy or radiochemotherapy between January 1995 and December 2005 were analyzed. All patients were restaged in accordance with the 1997 American Joint Committee on Cancer staging classification. There were 38 patients with Stage I NPC, 69 patients with Stage II NPC, 74 patients with Stage III NPC, and 71 patients with Stage IV at initial diagnosis. Radiotherapy alone was delivered to 78 patients (25%) and 174 patients (75%) were treated with radiotherapy combined with chemotherapy (cisplatin based). All tumors were confirmed pathologically as distinct malignancies. The median follow-up was 61 months (range: 14–155 months). Eigth patients (4.1%) developed second primary tumor. The tumor was located within the radiation field in only one patient. Tumor distribution localization was as follows; prostate cancer (1 patient), sinonasal carcinoma (1 patient), soft tissue sarcoma (1 patient), pancreas carcinoma (1 patient), tongue cancer (1 patient), mediastinal Non-Hodgkin lymphoma (1 patient), lung cancer (2 patients). Median time between the diagnosis of two distinct tumors was 21 months (range: 7–154). Age, gender, stage, chemotherapy and total radiation dose to the nasopharynx did not influence the risk of second primary tumor During the follow-up 4 patients died due to the second primary tumors. The majority of secondary primary tumors occur in the upper aerodigestive tract with a short latency period. The increased incidence of cancer in patients with NPC after treatment most likely is not related directly to radiotherapy.