Management of indeterminate pulmonary nodules (<1 cm) newly detected during the follow-up of nasopharyngeal carcinoma patients

Aim To investigate the management for the indeterminate pulmonary nodules newly detected during the follow-up for nasopharyngeal carcinoma (NPC) patients. Methods Indeterminate pulmonary lesions were identified by searching medical records of NPC patients, who were followed-up with thoracic CT between April 2008 and February 2014. Indeterminate pulmonary nodules were defined as opacities that may be solitary or multiple, which were <1 cm in size and not calcified. Nodules which were followed-up for at least two years, were included into analysis. The nodules with growth were considered as metastatic lesions and those which remained stable or regressed were defined as benign. The relations between the risk of the nodules to develop into metastatic lesions and clinical features and characteristics of nodules were analyzed. Results Through a median follow-up of 50 months, the majority (81 of 102, 79.4%) had no change in the size of nodules. The nodules have regressed in 11 patients. There were 10 (9.8%) cases with progression at the follow-up. The 10 patients were considered to have lung metastases, for whom continuous increases of lesions were revealed. The volume doubling time of the increasing nodules ranged from 34 to 105 days. The nodules emerging within two years after primary therapies were more likely to develop into metastatic lesions (P = 0.043). Conclusion Ten percent of the indeterminate pulmonary nodules represent metastatic diseases. A short-interval follow-up is recommended and if the nodules remain stable after six months follow-up, it may be proper to prolong the interval of follow-up.