title: Tissue compliance meter is a more reproducible method of measuring radiation-induced fibrosis than late effects of normal tissue-subjective objective management analytical in patients treated with intracavitary brachytherapy accelerated partial breast irradiation: results of a prospective trial.
abstract: Identification of radiation-induced fibrosis (RIF) remains a challenge with Late Effects of Normal Tissue-Subjective Objective Management Analytical (LENT-SOMA). Tissue compliance meter (TCM), a non-invasive applicator, may render a more reproducible tool for measuring RIF. In this study, we prospectively quantify RIF after intracavitary brachytherapy (IB) accelerated partial breast irradiation (APBI) with TCM and compare it with LENT-SOMA. Thirty-nine women with American Joint Committee on Cancer Stages 0-I breast cancer, treated with lumpectomy and intracavitary brachytherapy delivered by accelerated partial breast irradiation (IBAPBI), were evaluated by two raters in a prospective manner pre-IBAPBI and every 6 months post-IBAPBI for development of RIF, using TCM and LENT-SOMA. TCM classification scale grades RIF as 0 = none, 1 = mild, 2 = moderate, and 3 = severe, corresponding to a change in TCM (ΔTCM) between the IBAPBI and nonirradiated breasts of ≤2.9, 3.0-5.9, 6.0-8.9, ≥9.0 mm, respectively. LENT-SOMA scale employs clinical palpation to grade RIF as 0 = none, 1 = mild, 2 = moderate, and 3 = severe. Correlation coefficients-Intraclass (ICC), Pearson (r), and Cohen's kappa (κ)-were employed to assess reliability of TCM and LENT-SOMA. Multivariate and univariate linear models explored the relationship between RIF and anatomical parameters [bra cup size], antihormonal therapy, and dosimetric factors [balloon diameter, skin-to-balloon distance (SBD), V150, and V200]. Median time to follow-up from completion of IBAPBI is 3.6 years (range, 0.8-4.9 years). Median age is 69 years (range, 47-82 years). Median breast cup size is 39D (range, 34B-44DDD). Median balloon size is 41.2 cc (range, 37.6-50.0 cc), and median SBD is 1.4 cm (range, 0.2-5.5 cm). At pre-IBAPBI, TCM measurements demonstrate high interobserver agreement between two raters in all four quadrants of both breasts ICC ≥ 0.997 (95% CI 0.994-1.000). After 36 months, RIF is graded by TCM scale as 0, 1, 2, and 3 in 10/39 (26%), 17/39 (43%), 9/39 (23%), and 3/39 (8%) of patients, respectively. ΔTCM ≥6 mm (moderate-severe RIF) is statistically different from ΔTCM ≤3 mm (none-mild RIF) (p < 0.05). At 36 months post-IBAPBI, TCM measurements for two raters render ICC = 0.992 (95% CI 0.987-0.995) and r = 0.983 (p < 0.0001), whereas LENT-SOMA demonstrates κ = 0.45 (95% CI 0.18-0.80). SBD and V150 are the only factors closest to 0.05 significance of contributing to RIF. This prospective study indicates that TCM is a more reproducible method than LENT-SOMA in measuring RIF in patients treated with IBAPBI. This tool renders a promising future application in assessing RIF.
authors.affiliation: Stich Radiation Oncology, Weill Cornell Medical College of Cornell University, New York, NY, USA. gaw9008@med.cornell.edu
authors.forename: A Gabriella
authors.initials: AG
authors.lastname: Wernicke
authors.forename: Eleni A
authors.initials: EA
authors.lastname: Greenwood
authors.forename: Shana
authors.initials: S
authors.lastname: Coplowitz
authors.forename: Bhupesh
authors.initials: B
authors.lastname: Parashar
authors.forename: Fridon
authors.initials: F
authors.lastname: Kulidzhanov
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Christos
authors.forename: Andrew
authors.initials: A
authors.lastname: Fischer
authors.forename: Dattatreyudu
authors.initials: D
authors.lastname: Nori
authors.forename: Kun S Clifford
authors.initials: KS
authors.lastname: Chao
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects*; D001940:Breast / Q000473:pathology / Q000528:radiation effects*; D001943:Breast Neoplasms / Q000532:radiotherapy*; D005260:Female; D005355:Fibrosis; D006801:Humans; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results