NTCP modeling and dose–volume correlations for acute xerostomia and dry eye after whole brain radiation

Radiation Oncology

Panayiotis Mavroidis¹  Trevor J. Royce¹  Bhishamjit S. Chera¹  Shiva K. Das¹  Lawrence B. Marks¹  Kevin A. Pearlstein¹  Dominic H. Moon¹  Ashley A. Weiner¹  Colette J. Shen¹  Kyle Wang¹  Victoria Xu¹ 

[1] Department of Radiation Oncology, University of North Carolina, 101 Manning Dr., 27599-7512, Chapel Hill, NC, USA;

关键词: Radiobiological parameters;    Xerostomia;    Dry eye;    Whole brain radiation therapy;    NTCP;    LKB;    Relative seriality;   

DOI  :  10.1186/s13014-021-01786-6

来源: Springer

【 摘 要 】

BackgroundWhole brain radiation (WBRT) may lead to acute xerostomia and dry eye from incidental parotid and lacrimal exposure, respectively. We performed a prospective observational study to assess the incidence/severity of this toxicity. We herein perform a secondary analysis relating parotid and lacrimal dosimetric parameters to normal tissue complication probability (NTCP) rates and associated models.MethodsPatients received WBRT to 25–40 Gy in 10–20 fractions using 3D-conformal radiation therapy without prospective delineation of the parotids or lacrimals. Patients completed questionnaires at baseline and 1 month post-WBRT. Xerostomia was assessed using the University of Michigan xerostomia score (scored 0–100, toxicity defined as ≥ 20 pt increase) and xerostomia bother score (scored from 0 to 3, toxicity defined as ≥ 2 pt increase). Dry eye was assessed using the Subjective Evaluation of Symptom of Dryness (SESoD, scored from 0 to 4, toxicity defined as ≥ 2 pt increase). The clinical data were fitted by the Lyman–Kutcher–Burman (LKB) and Relative Seriality (RS) NTCP models.ResultsOf 55 evaluable patients, 19 (35%) had ≥ 20 point increase in xerostomia score, 11 (20%) had ≥ 2 point increase in xerostomia bother score, and 13 (24%) had ≥ 2 point increase in SESoD score. For xerostomia, parotid V10Gy–V20Gy correlated best with toxicity, with AUC 0.68 for xerostomia score and 0.69–0.71 for bother score. The values for the D50, m and n parameters of the LKB model were 22.3 Gy, 0.84 and 1.0 for xerostomia score and 28.4 Gy, 0.55 and 1.0 for bother score, respectively. The corresponding values for the D50, γ and s parameters of the RS model were 23.5 Gy, 0.28 and 0.0001 for xerostomia score and 32.0 Gy, 0.45 and 0.0001 for bother score, respectively. For dry eye, lacrimal V10Gy–V15Gy were found to correlate best with toxicity, with AUC values from 0.67 to 0.68. The parameter values of the LKB model were 53.5 Gy, 0.74 and 1.0, whereas of the RS model were 54.0 Gy, 0.37 and 0.0001, respectively.ConclusionsXerostomia was most associated with parotid V10Gy–V20Gy, and dry eye with lacrimal V10Gy–V15Gy. NTCP models were successfully created for both toxicities and may help clinicians refine dosimetric goals and assess levels of risk in patients receiving palliative WBRT.

【 授权许可】

CC BY