Top Line: What are the patterns of lymph node recurrence after lung SBRT?
The Study: This retrospective review from 11 centers in the Korean Radiation Oncology Group (KROG) identified 114 patients who had first recurrence in regional lymph nodes following lung SBRT. Almost all patients (99%) had PET/CT staging, and 42.1% had pathologic mediastinal lymph node staging. The median dose was 60 Gy in 5 fractions, and 92.1% received a BED10 ≥100Gy. The median time from SBRT to regional recurrence was 11.4 months, and most (61.4%) were detected by PET/CT with 19.3% having pathologic confirmation. As might be expected, the most commonly involved nodal stations were the hilum (47%), subcarina (42.5%), and ipsilateral paratracheal (40.6%). Half of these recurrences were only in lymph nodes with the rest having synchronous distant (37.7%), local (21.9%), or lobar (5.3%) recurrence. These patterns suggest different biological sources of recurrence. The high rate of synchronous local recurrence suggests a subset of tumors that are likely radioresistant while those with early node-only recurrence may represent occult metastatic disease present at initial diagnosis. In fact, median time to node-only recurrence was significantly shorter than time to synchronous recurrences (9.2 v 14.9 months). Survival after recurrence was poor with a 1 year OS rate of 38.2%.
TBL: Half of lymph node recurrences after lung SBRT are only in the mediastinal nodes, and nearly 80% of patients have disease confined to the chest. Nevertheless, these patients have a high rate of subsequent failure and poor survival outcomes. | Lee, Radiother Oncol 2023
The Study: This retrospective review from 11 centers in the Korean Radiation Oncology Group (KROG) identified 114 patients who had first recurrence in regional lymph nodes following lung SBRT. Almost all patients (99%) had PET/CT staging, and 42.1% had pathologic mediastinal lymph node staging. The median dose was 60 Gy in 5 fractions, and 92.1% received a BED10 ≥100Gy. The median time from SBRT to regional recurrence was 11.4 months, and most (61.4%) were detected by PET/CT with 19.3% having pathologic confirmation. As might be expected, the most commonly involved nodal stations were the hilum (47%), subcarina (42.5%), and ipsilateral paratracheal (40.6%). Half of these recurrences were only in lymph nodes with the rest having synchronous distant (37.7%), local (21.9%), or lobar (5.3%) recurrence. These patterns suggest different biological sources of recurrence. The high rate of synchronous local recurrence suggests a subset of tumors that are likely radioresistant while those with early node-only recurrence may represent occult metastatic disease present at initial diagnosis. In fact, median time to node-only recurrence was significantly shorter than time to synchronous recurrences (9.2 v 14.9 months). Survival after recurrence was poor with a 1 year OS rate of 38.2%.
TBL: Half of lymph node recurrences after lung SBRT are only in the mediastinal nodes, and nearly 80% of patients have disease confined to the chest. Nevertheless, these patients have a high rate of subsequent failure and poor survival outcomes. | Lee, Radiother Oncol 2023