Introduction Patients treated with stereotactic body radiation therapy (SBRT) for early stage non-small cell lung cancer (NSCLC) are subject to locoregional and distant recurrence, as well as the formation of second primary lung cancers (SPLC). The optimal surveillance regimen for patients treated with SBRT for early-stage NSCLC remains unclear, and herein we investigated the post-treatment recurrence patterns and development of SPLC. Methods Three-hundred and sixty-six patients with pathologically proven inoperable early-stage NSCLC treated with SBRT between 2006 and 2013 were assessed. Patients underwent a CT scan of the chest every 3 months during years 1 and 2, every 6 months during years 3 and 4, and annually thereafter. Competing risks analysis was used for all time-to-event analyses. Results With a median follow up of 23 months, the 2-year cumulative incidence of local, nodal and distant failures were 12.2%, 16.1%, and 15.5%, respectively. Of patients with disease progression post-SBRT (n=108), 84% (n=91) occurred within the first two years. Five percent (n=19) of patients developed a SPLC. The median time to development of SPLC was 16.5 months (range 6.5 to 71.1 months), with 33% (n=6) of these patients developing SPLCs after two years. None of the never smokers, but 4% of former and 15% of current tobacco smokers developed a SPLC (p=0.005). Conclusion Close monitoring with routine CT scans within the first 2 years after SBRT is effective in detecting early disease progression. In contrast, the risk for developing a SPLC remains elevated beyond 2 years, particularly in former and current smokers.

Introduction Higher target conformity and better sparing of organs at risk with modern radiotherapy (RT) may result in higher tumor control and less toxicities. In this study, we compare our institutional multimodality therapy experience of adjuvant chemotherapy and hemithoracic intensity-modulated pleural RT (IMPRINT) to previously used adjuvant conventional RT (CONV) in patients with malignant pleural mesothelioma (MPM) treated with lung-sparing pleurectomy/decortication (P/D). Methods We analyzed 209 patients who underwent P/D and adjuvant RT (n[CONV]=131, n[IMPRINT]=78) for MPM between 1974 and 2015. The primary endpoint was overall survival (OS). The Kaplan-Meier method and Cox proportional hazards model were used to calculate OS; competing ri sks analysis was performed for local failure-free (LFFS) and progression-free survival (PFS). Univariate (UVA) and multivariate analysis (MVA) was performed with relevant clinical and treatment factors. Results The median age was 64 years, 80% were male. Patients receiving IMPRINT had significantly higher rates of epithelial histology, advanced pStage and chemotherapy treatment. OS was significantly higher after IMPRINT (median 20.2 vs 12.3 months, p=0.001). Higher Karnofsky performance score (KPS), epithelioid histology, macroscopically complete resection (MCR), and use of chemotherapy/IMPRINT were found to be significant factors for longer OS upon MVA. No significant predictive factors were identified for local failure or progression. Fewer patients developed grade ≥2 esophagitis after IMPRINT compared to CONV (23% vs 47%). Conclusions Trimodality therapy including adjuvant hemithoracic IMPRINT, chemotherapy, and P/D is associated with promising OS rates and decreased toxicities in patients with MPM. Dose constraints should be applied vigilantly to minimize serious adverse events.

SBRT compared to CONV is associated with improved LF rates and OS. Our data supports the continued use and expansion of SBRT as the standard of care treatment for inoperable early-stage NSCLC.

In this largest reported retrospective study, no OS differences were associated with PMRT, which suggests that PMRT may not benefit every patient with microscopic nodal disease.

No abstract