Metastatic characteristics of lymph node in supraclavicular zone and radiotherapy target volume for limited-stage small cell lung cancer

Abstract

To explore the reasonable radiotherapy range by analyzing the characteristics of supraclavicular lymph node metastasis in limited-stage small cell lung cancer (LS-SCLC). From January 2005 to December 2011, patients of LS-SCLC were reviewed. Supraclavicular zone was further divided into five subgroups including para-recurrent laryngeal nerve (region I and region II ), para-internal jugular vein (region III ), supraclavicular region (region IV), as well as the other regions except for the mentioned above (region V). The characteristics of the lymph nodes in each region were analyzed. The supraclavicular lymph node metastasis was found in 60 patients, with a positive rate of 34.5%. In multivariate Logistic regression analysis,intra-thoracic lymph node metastasis in the lymph node stations of level 2 and 3 were found to be the risk factors of supraclavicular lymph node metastasis (P = 0.006,P = 0.000). Our data suggests that the frequencies of metastasis in region I and III were much higher than those in the other areas.Among the sixty patients with supraclavicular lymph node metastasis, 95.0% were found at region I or III while the incidence of skip metastasis was only 5.0%. It is advisable to contain the bilateral supraclavicular nodes in patients with mediastinal lymph nodes metastasis to the level 2 or 3 for elective radiation target volume.The clinical target volume (CTV) exterior margin containing the outer margin of internal jugular vein may be suitable.