Correlation between toxicity and dosimetric parameters for adjuvant intensity modulated radiation therapy of breast cancer: a prospective study

• Published in: Scientific reports Vol. 11; no. 1; p. 3626
• Main Authors: Pasquier, David, Bataille, Benoit, Le Tinier, Florence, Bennadji, Raoudha, Langin, Hélène, Escande, Alexandre, Tresch, Emmanuelle, Darloy, Franck, Carlier, Damien, Crop, Frederik, Lartigau, Eric
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 11.02.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 692/4028; 692/4028/67; Adverse events; Breast cancer; Chemotherapy; Esophagus; Humanities and Social Sciences; Hyperpigmentation; Irradiation; Life Sciences; Lymph nodes; Mastectomy; multidisciplinary; Multivariate analysis; Patients; Radiation therapy; Science; Science (multidisciplinary); Skin; Surgery; Survival; Toxicity
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-021-83159-3

ORCID: 0000–0001-6019–7309 . In the treatment of breast cancer, intensity-modulated radiation therapy (IMRT) reportedly reduces the high-dose irradiation of at-risk organs and decreases the frequency of adverse events (AEs). Comparisons with conventional radiotherapy have shown that IMRT is associated with lower frequencies of acute and late-onset AEs. Here, we extended a prospective, observational, single-center study of the safety of IMRT to a second investigating center. Patients scheduled for adjuvant IMRT after partial or total mastectomy were given a dose of 50 Gy (25 fractions of 2 Gy over 5 weeks), with a simultaneous integrated boost in patients having undergone conservative surgery. 300 patients were included in the study, and 288 were analyzed. The median follow-up period was 2.1 years. The 2-year disease-free survival rate [95% CI] was 93.4% [89.2–96.0%]. Most AEs were mild. The most common AEs were skin-related—mainly radiodermatitis [in 266 patients (92.4%)] and hyperpigmentation (in 178 (61.8%)). 35% and 6% of the patients presented with grade 2 acute skin and esophageal toxicity, respectively. Only 4 patients presented with a grade 3 event (radiodermatitis). Smoking (odds ratio) [95% CI] = 2.10 [1.14–3.87]; p = 0.017), no prior chemotherapy (0.52 [0.27–0.98]; p = 0.044), and D98% for subclavicular skin (1.030 [1.001–1.061]; p = 0.045) were associated with grade ≥ 2 acute AEs. In a univariate analysis, the mean dose, (p < 0.0001), D2% (p < 0.0001), D50% (p = 0.037), D95% (p = 0.0005), D98% (p = 0.0007), V30Gy (p < 0.0001), and V45Gy (p = 0.0001) were significantly associated with grade ≥ 1 acute esophageal AEs. In a multivariate analysis, D95% for the skin (p < 0.001), D98% for the subclavicular skin and low D95% for the internal mammary lymph nodes were associated with grade ≥ 1 medium-term AEs. The safety profile of adjuvant IMRT after partial or total mastectomy is influenced by dosimetric parameters. Trial registration : ClinicalTrials.gov NCT02281149.