Author: Gregory A Azzam, Danielle Cerbon, Laura Huang, Panayiotis Mavroidis, Diana Molinares, Stuart E Samuels, Sotirios Stathakis 👨🔬
Affiliation: Mary Bird Perkins Cancer Center, University of Miami Sylvester Comprehensive Cancer Center, Mount Vernan Rehabilitation Medicine Associates, Department of Radiation Oncology, University of Miami, University of North Carolina 🌍
Purpose: This study examines the correlation of different dose volume metrics of the skin, sternocleidomastoid (SCM) muscle and subcutaneous tissue (subcut) structures with the skin systemic sclerosis outcome data.
Methods: 88 patients, who received radiotherapy for head & neck tumors were used in this study. 43 patients had prior surgery and received 60-66Gy, whereas the rest 45 were prescribed to 70Gy. Scleroderma skin PRO (SSPRO) was recorded 12 months post-RT and a difference of ≥48 defined the clinical endpoint. The mean, max doses and a range (V5-V65) of dose volume metrics were derived from the DVHs of the skin, SCM and subcut structures and were correlated with the individual SSPRO scores. The area under the receiver operating characteristic curve (AUC) and odds ratio (OR) were used to evaluate the statistical correlations.
Results: Skin systemic sclerosis was observed in 16.3% and 13.3% of the patients with and without prior surgery, respectively. For the patients with prior surgery, the AUC values for skin, SCM and subcut were 0.71, 0.62 and 0.66 for V5, V45 and V10, respectively. OR showed statistical significance (0.04 and 0.05) for skin V5 and subcut V10 for values <30% and <25%, respectively. For the patients without prior surgery, the AUC values for skin, SCM and subcut were 0.66, 0.70 and 0.74 for V5, V50 and V15, respectively. OR showed statistical significance (0.05 and 0.03) for SCM V50 and subcut V15 for values <95% and <20%, respectively.
Conclusion: Based on the correlations between different dose metrics of skin, sternocleidomastoid muscle and subcutaneous tissue structures with the SSPRO scores, skin V5<30% and subcut V10<25% in the patient cohort with prior surgery and SCM V50<95% and subcut V15<20% in the patient cohort without prior surgery were found to significantly reduce the risk for skin systemic sclerosis.