An exploration of radiation-induced side effects for palliative patients treated with volumetric modulated arc therapy versus conventional radiotherapy to the spine.

PURPOSE: Given the increased frequency of volumetric modulated arc therapy (VMAT) in palliative radiation therapy planning, this study compares differences in patient-reported side effects for palliative patients treated with radiation therapy to the spine using VMAT versus conventional radiation therapy (CRT) techniques.

METHODS AND MATERIALS: A single-centre retrospective study examined patient-reported Edmonton Symptom Assessment Scores (ESAS) for palliative patients with spinal metastases. Scores were stratified by technique and site (C/CT Spine, T/TL Spine & L/LS Spine). Average ESAS scores were calculated, and T-tests were used to detect significant differences (p<0.05) between ESAS baseline and treatment scores. The planning target volume (PTV) length of each treated site was measured, and Pearson's r correlational coefficients were calculated to identify correlations between PTV length and patient-reported symptoms.

RESULTS

For CRT patients treated to the lumbar/lumbosacral (L/LS) spine, significantly lower anxiety scores (p=0.0498) were noted on treatment (n = 9) when compared with baseline (n = 24). CRT patients treated to the T/TL spine were significantly more tired and drowsy during treatment (n = 32) when compared with CRT baseline scores (n = 53; pTiredness=0.0175; pDrowsiness= 0.0102), which was not observed in the VMAT study group. All CRT patient subgroups also experienced more drowsiness and tiredness on treatment compared with VMAT patients (pDrowsiness=0.2003; pTiredness=0.0852). VMAT patients treated to the thoracic/thoracolumbar (T/TL) spine (n = 43) reported a significant decrease in appetite compared with CRT patients (n = 24; p = 0.0357). The remaining scores demonstrate no significant differences between cohorts for the t-test analysis. A moderate positive correlation (r = 0.5741, n = 10) between PTV length and nausea scores was detected in CRT patients treated to the L/LS spine, which was not observed in the VMAT study group.

CONCLUSIONS

Although differences in patient-reported symptoms exist when comparing CRT versus VMAT for palliative spine radiation therapy, these differences are not clinically significant, and both techniques are well-tolerated.