Room: Exhibit Hall
Purpose: To measure the effect of radiation dose and volume on patient-reported quality of life (QOL) outcomes and clinical toxicity of lung cancer patients up to 36 months after SBRT.
Methods: Non-small cell lung cancer (NSCLC) patients, n=122, received SBRT (12 Gy x 4). Symptoms including cough, dyspnea, fatigue, and pneumonitis were measured at baseline (before treatment), after treatment and 3, 6, 12, 18, 24, and 36 months post-treatment. Toxicity, graded from zero to five, followed the Charlson comorbidity and toxicity index. Quality of life was determined using the previously-validated Functional Assessment of Cancer Therapy-Trial Outcome Index (FACT-TOI) Lung questionnaire which incorporated three subscale endpoints: lung subscale (LSC), physical well-being (PWB) and functional well-being (FWB). Dosimetric parameters included the mean lung radiation dose (MLD) and the volume of normal lung receiving at least 5, 10, 13 or 20 Gy (V5, V10, V13, and V20), esophagus receiving at least 5 Gy, maximum and mean dose (E_V5, E_Dmax, and E_Dmean) obtained from the treatment plan. Pearson correlation and t-test analyses were used to measure correlations between lung metrics with QOL and toxicities.
Results: SBRT produced minimal toxicities. QOL (TOI, LSC, PWB, or FWB) at 24 and 36 months post-treatment were significantly correlated with V5, V10, V13, V20, and MLD for stage I&II (p<0.05). Moreover, correlations were found for dyspnea with V10 and V13 for stage I&II, for esophagitis with E_V5 for stage III, and for dyspnea with V20 for stage IV. Overall, QOL improved for patients with stage IV lung cancer at 18, 24, and 36 months.
Conclusion: Lung SBRT treatment for patients with NSCLC, using a 12 Gy x 4 dose regimen, was well tolerated. Unique QOL data (not previously reported) and clinical toxicities at up to 36 months follow up showed correlations with lung dose and subvolumes for different stages.
Funding Support, Disclosures, and Conflict of Interest: This work was supported in part by a research grant from Varian Medical Systems, Palo Alto, CA