Top Line: Can SABR dose be individualized for patients with lung tumors?
The Study: In practice, we often individualize SABR dose depending on lung tumor size and location. While these doses are well supported by data, there are few individual studies analyzing outcomes across this entire dose spectrum. iSABR was a nonrandomized, phase 2 trial that sought to achieve high local control and low toxicity using individualized SABR dosing for lung tumors. The trial included 217 patients with 285 tumors including primary lung cancers and metastases. Eligible patients had either one tumor with a sum of orthogonal diameters <20 cm or multiple (up to 4) tumors with no individual tumor having a sum of orthogonal diameters >15 cm. Small tumors (≤10cc) received 25 Gy in 1 fraction (BED10 87.5Gy) if peripheral, 40 Gy in 4 fractions (BED10 80Gy) if central, and 50 Gy in 4 fractions if colorectal metastasis. Over half of tumors (55%) were small and peripheral and treated with 25 Gy x 1. Medium tumors (11-30cc) received 50 Gy in 4 fractions whether central or peripheral. Large tumors (>30cc) received 54 Gy in 3 fractions if peripheral and 60 Gy in 8 fractions if central. Local recurrence occurred in 9% of tumors, and ⅔ of local recurrences were in-field. Among those with first primary NSCLC, local control was 97% at 1 years. Among those with recurrent or multiple NSCLC, local control was 94% at 1 year. Among those with metastases, local control was 96% at 1 year. Notably, the rate of recurrence was <10% in patients with small tumors treated with a BED10 <100 Gy. The rate of grade 3+ toxicity was just 5%, and the rate of grade 3 pneumonitis was just 1%.
TBL: This prospective study confirms that individualized SABR dosing for a broad spectrum of lung tumors and metastases results in >90% local control at 1 year with low toxicity. | Gensheimer, JAMA Oncol 2023
The Study: In practice, we often individualize SABR dose depending on lung tumor size and location. While these doses are well supported by data, there are few individual studies analyzing outcomes across this entire dose spectrum. iSABR was a nonrandomized, phase 2 trial that sought to achieve high local control and low toxicity using individualized SABR dosing for lung tumors. The trial included 217 patients with 285 tumors including primary lung cancers and metastases. Eligible patients had either one tumor with a sum of orthogonal diameters <20 cm or multiple (up to 4) tumors with no individual tumor having a sum of orthogonal diameters >15 cm. Small tumors (≤10cc) received 25 Gy in 1 fraction (BED10 87.5Gy) if peripheral, 40 Gy in 4 fractions (BED10 80Gy) if central, and 50 Gy in 4 fractions if colorectal metastasis. Over half of tumors (55%) were small and peripheral and treated with 25 Gy x 1. Medium tumors (11-30cc) received 50 Gy in 4 fractions whether central or peripheral. Large tumors (>30cc) received 54 Gy in 3 fractions if peripheral and 60 Gy in 8 fractions if central. Local recurrence occurred in 9% of tumors, and ⅔ of local recurrences were in-field. Among those with first primary NSCLC, local control was 97% at 1 years. Among those with recurrent or multiple NSCLC, local control was 94% at 1 year. Among those with metastases, local control was 96% at 1 year. Notably, the rate of recurrence was <10% in patients with small tumors treated with a BED10 <100 Gy. The rate of grade 3+ toxicity was just 5%, and the rate of grade 3 pneumonitis was just 1%.
TBL: This prospective study confirms that individualized SABR dosing for a broad spectrum of lung tumors and metastases results in >90% local control at 1 year with low toxicity. | Gensheimer, JAMA Oncol 2023