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Nasopharyngeal carcinoma (NPC) accounts for 0.7% of all new cancer cases and for 0.8% of all cancer deaths occurring across the world. Due to the concealed location of the tumor, most patients are locally advanced or distantly metastatic at the time of the initial diagnosis. The incidence of synchronous metastasis in NPC range from 4% to 10%. Oligometastatic (OM) NPC is a distinctive subset with better prognosis. Increasing evidences support that prolonged overall survival (OS) is possible for patients undertaking appropriate treatments. The aim of our study is to describe the epidemiological and clinical features of OM entity and to highlight the role of locoregional (LR) treatment into the primary site.  

From January 2009 to December 2019, we enrolled 24 OM patients with histologically confirmed nasopharyngeal undifferentiated carcinoma. We have considered OM as a limited number of organ and site involvement (e.g., 1–2 organ metastases or < 5 metastatic lesions). The TNM classification used was the 8th edition published by the American Joint Committee on Cancer (AJCC). We only included patients who underwent a first line of chemotherapy with good or stable response of the lesions according to RECISTv1.1. Only a good Karnofsky performance status (KPS >70) were selected for LR treatment with radiotherapy and concomitant chemotherapy.

The median age was 43.4 years. The sex-ratio was 3. Tumor were classified as T4 and T3 respectively in 50% and 16.7% of cases. Regional Lymph nodes invasion were classified on N3, N2 and N1 in 50%, 30% and 20% respectively. Bone metastases were the most common site (68.4%), followed by pulmonary metastases (21%) and liver metastases (15.8%). Sixty-two percent of patients had a single metastasis. Four to six cycles of 5FU-cisplatin were completely administered (41.6%). Partial response was noted in 50% of cases. Locoregional radiation therapy with curative intent was delivered at the dose of 70 Gy on the tumor and 54 Gy on prophylactic areas. Metastatic sites were irradiated in only four patients. Concurrent chemotherapy were conducted in all patients. Nevertheless, 16.7% of patient developed grade 3-4 toxicity. Locoregional treatment response was complete in 40% of cases. After a median follow-up of 40 months, the 1- and 3-year overall survival rates was 70% and 40%, respectively while the 1 and 3-year progression-free survival was 60% and 30%, respectively. 

There is no established consensus yet on the best treatment strategy for OM NPC patients. Radical LR radiotherapy could prolong the overall survival. Several studies are in perspective to resolve fundamental questions in particular the best sequences treatment strategies as well as the role integration of immunotherapy to improve survival (eg. the ongoing KEYNOTE 122 trial).