Natural History of subcentimeter pulmonary nodules in clinical stage I seminoma patients

Abstract

Introduction and objective

Subcentimeter pulmonary nodules (SPN) found in clinical stage I (CS I) seminoma may be early pulmonary metastases or incidental, benign entities that may lead to patient anxiety and overtreatment. This study aims to demonstrate the incidence and natural history of SPN in CS I seminoma patients.

Methods

A retrospective study reviewing the medical records of CS I seminoma patients treated at UC San Diego Health between 2003 and 2023. Data collection included demographics, serum tumor markers (STM), imaging reports, pathologic findings, treatment records, and records of disease relapse. We described SPN as a finding either from a chest X-ray (CXR) or a computed tomography (CT) scan of the chest at the time of seminoma diagnosis, with a size <1cm. The incidence of SPN and relationship with disease relapse was explored.

Results

79 patients with CS I seminoma were included in the study, and mean follow-up time was 40 months. Our general practice is to observe all patients with stage I seminoma except under extenuating circumstances. Among them, 21 patients were found to have SPN, all which were diagnosed on CT scan of chest, resulting in an incidence rate of 26.6%. Notably, there was no statistically significant difference in the occurrence of SPN between patients with CS IA and CS IB (27.9% and 22.2%, respectively, P = 0.227). Four patients (5%) experienced disease relapse. None of the patients that had a relapse had an incidental subcentimeter nodules. Six patients received adjuvant chemotherapy (CMT); 1 patient had a pulmonary nodule and did not relapse; 1 patient experienced disease relapse without nodule. 10 patients underwent adjuvant radiation (RT), with no recurrence observed despite 4 of them having nodules. Additionally, 5 patients with nodules received adjuvant CMT or RT; none recurred. 16 patients with nodules were under surveillance, none recurred.

Conclusions

The incidence of SPN in CS I seminoma patient is high. Subcentimeter nodules do not appear to be related to risk of disease relapse. Our findings suggest that patients with CS I seminoma and incidental SPN can be counseled that this is a common, clinically insignificant finding. Further validation in a larger population is necessary.