Should All Medically Inoperable Patients with Early-Stage NSCLC Need SBRT Treatment?

• Published in: International journal of radiation oncology, biology, physics Vol. 120; no. 2; p. e6
• Main Authors: Biswas, T., Vempati, P., Efird, J.T., Zheng, Y., Podder, T.K.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.10.2024
• ISSN: 0360-3016
• DOI: 10.1016/j.ijrobp.2024.07.1792

The current standard of care for medically inoperable Early-stage NSCLC is stereotactic body radiosurgery (SBRT) based on the findings from RTOG 0236 trial. However, in comparison with the surgical literature for medically operable patients, 3-year survival with SBRT is consistently inferior likely owing to associated medical co-morbidities while local control remains comparable. While it has been reported sparsely that Charlson co-morbidity Index (CCI) and performance status (PS) are important prognostic factors for treatment outcome, they are not routinely incorporated in the treatment decision of these vulnerable patient population with an early-stage NSCLC. In this study we have investigated the impact of age adjusted CCI (aCCI) and Eastern cooperative Oncology Group (ECOG) PS on survival following SBRT treatment after adjusting for other patient, tumor and treatment factors. A total of 374 patients who underwent SBRT for T1 and T2 NSCLC at our institute between 2012 and 2020 were considered for this study. Patient factors including age, sex, aCCI, ECOG PS; tumor factor including location, histology, grade, T-stage and treatment factors including GTV volume, PTV volume and minimum, maximum and mean BED (Biologically effective dose) to the targets were collected. Overall survival (OS) was computed from the date of diagnosis until the date of death. Patients alive on their last FU were censored. SAS (version 9.0) was used for statistical analysis. OS was estimated using Kaplan-Meier survival analysis method and finally, multivariable model was created with adjustment of all variables. Patients’ median age was 75 (IQR 14) with a median FU of 2.6 years (IQR = 2.7). 50% patients were female, 49% had adenocarcinoma, 72% had upper lobe tumors, 58% had right sided tumors, 78% had peripheral tumors and 86% had T1 tumors. 4.0 (95% CI = 3.3-5).), with 1-year and 3-year OS were 88% and 58%, respectively. On Univariable analysis, age, aCCI, ECOG PS, sex and T-stage were statistically significant. On multivariable analysis, higher aCCI (HR 1.9, p = 0.042), higher ECOG PS (HR 2.4, p = 0.019), higher T-stage (HR1.7, p = 0.33), male sex (HR 1.7, p = 0.41) and lower lobe tumor (HR 1.4, p = 0.049) were adverse. No treatment related factors including maximum, minimum, and mean BED to the GTV, PTV were significant. After adjustment with T-stage, GTV and PTV volumes lost their significance. This is one of the largest series showing importance of co-morbidity and baseline ECOG PS are significant factors in predicting overall survival in addition to known clinical factors. For poor PS patients with significant co-morbidities, a geriatric assessment will be beneficial in deciding treatment recommendation to avoid any treatment that may not affect the overall survival. Future work is in progress to develop a nomogram to try to select patients who would most benefit from SBRT treatment.