184. A retrospective study on acute and late toxicity in early breast cancer radiotherapy: Preliminary analysis on Field in Field technique. (December 2018)

• Record Type: Journal Article
• Authors: Camarda, M.; Mascioni, F.; D'Avenia, P.; Di Nicola, E.; Montani, L.; Rossi, G.; Giannini, M.; Fattori, S.
• Is Part Of: Physica medica. Volume 56(2018)Supplement 2
• Page Start: 175
• Publication Date: 2018-12
• Subjects: Medical physics -- Periodicals; Biophysics -- Periodicals; Biophysics -- Periodicals; Imagerie médicale -- Périodiques; Radiothérapie -- Périodiques; Rayons X -- Sécurité -- Mesures -- Périodiques; Physique -- Périodiques; Médecine -- Périodiques; 610.153
• DOI: 10.1016/j.ejmp.2018.04.195
• Languages: English
• ISSNs: 1120-1797

Abstract

Abstract: Purpose: Field-in-Field (FinF) technique improves dose coverage and homogeneity with respect to standard wedged fields (WF). The aim of our analyses is to investigate whether acute or late toxicities are influenced by plan technique. Methods: 374 patients at early stage breast cancer were treated using either WF or FinF technique. For each patient, baseline clinical characteristics were recorded, treatment characteristics and dosimetric values were extracted from plans. Acute and late toxicities were assessed according to CTCAE-v3 criteria. The statistically significant correlations were assessed in the whole group, then comparisons were performed by grouping patients according to plan technique. Results: Median follow-up time was 593 days (range 18–966). Patient treated with FinF technique were 149 with a median follow-up time of 436 days, shorter than pts treated with WF technique (764 days). The two technique subgroups were homogeneous according to baseline clinical characteristics. In the whole group factors significantly correlating with acute toxicity are dose prescription (degree of erythema P < 0.0001 and desquamation P < 0.0001), breast volume (degree of erythema P < 0.0001, desquamation P < 0.0001, desquamation sites P = 0.0028), age (erythema resolution time P = 0.02). Factors significantly correlated with late toxicity are V95 (fibrosis P = 0.005, degree of breast lymphedema P = 0.0007), breast volume (scar retraction P = 0.03, late mastitis P = 0.01, degree of breast lymphedema P < 0.0001) and age (pain P = 0.03, hyperpigmentation P < 0.0001). At univariate analysis there was no evidence of statistically significant differences between the two technique subgroups for each acute or late toxicity. Dosimetric values were also analyzed resulting in a better dose coverage (for V95: P < 0.0001) in spite of higher doses to OAR's (for lung mean dose: P = 0.0003). Conclusions: Preliminary statistic analysis shows that FinF technique provides better dose coverage with respect to WF without affecting acute or late toxicity in spite of the shorter follow-up time.