Mediastinal and Hilar Lymphadenopathy Treated by SABR

Abstract

<h3>Purpose/Objective(s)</h3> Mediastinal and hilar lymphadenopathy (MHL) is a frequent pattern of cancer spread, most frequent in lung cancer, but also in others primary disease. Traditionally, the local treatments included surgical resection or conventional RT, with or without systemic treatments. Recently, there is a considerable interest in the application of stereotactic ablative radiotherapy (SABR) for MHL. Safety and efficacy of SABR for mediastinal and hilar lymphadenopathy (MHL) have not yet been established. SABR treatment on ultra-central localizations has been found to be associated with higher rates of severe toxicity. Aim of this study is to evaluate the safety, clinical outcomes of survival and predictive factors of response of SABR on MHL. <h3>Materials/Methods</h3> One hundred and thirteen MHL were treated in 97 patients with SABR, from 2007 to 2021. Patients were more commonly affected by lung tumor (47%). The median age of patients was 67 (range 43-90). The schedule most represented was 30 Gy in 5 fractions (range 23-60 Gy in 1-8 fractions). The medium BED (10) was 81 Gy (range 37.5-120Gy). Twenty-six (23%) cases received a single fraction, 87 (77%) cases received multiple fractions. The patients were classified as oligorecurrent (52%), oligoprogressive (35%), oligometastatic (4%) and oligopersistent (9%). <h3>Results</h3> The median follow-up was 20 months (range 0-130 months). Acute toxicities were: five cases (4%) Grade 1 (in form of pain, fatigue, nausea, vomiting and cough), one case (0.9%) with anemia G2, one case (0.9%) died 3 days after treatment on mediastinal lymph node by esophageal bleeding, G5. One case (0.9%) presented late toxicity with dyspnea Grade 2. The rates of Local Control at 1 and 3 years were 90% and 84%, respectively. The rates of Loco Regional Nodal Control at 1 and 3 years were 84% and 75% respectively. The rates of Distant Nodal Control at 1 and 3 years were 93% and 84%, respectively. The rates of Distant Metastasis Free Survival at 1 and 3 years were 57% and 47%, respectively. The rates of Progression Free Survival at 1 and 3 years were 36% and 20%, respectively. The rates of Overall Survival at 1 and 3 years were 69% and 41%, respectively. Univariate analysis showed that the state of disease was statistically significant correlated with OS with better results for oligometastatic patients (p= 0,044). The number of metastases was statistically significant correlated with OS (p= 0,0046) and with DMFS (p= 0,0121). The DMFS was also correlated with number of previous systemic therapy. Patients receiving more than one line (range: 2-4 lines) of systemic therapy prior to SABR presented the worst results (p=0,0065). <h3>Conclusion</h3> In conclusion, our study showed that SABR on MHL is able to achieve excellent results in terms of local control with acceptable toxicity. More prospective studies are needed to confirm these results.