Assessment of Pain as a Sequela in Patients Treated with Intracavitary Brachytherapy Accelerated Partial Breast Irradiation (IBAPBI): Preliminary Results of a Prospective Study

To assess pain rates and relationship to radiation-induced fibrosis (RIF) in patients treated with intracavitary brachytherapy accelerated partial breast irradiation (IBAPBI). Thirty-nine patients treated with IBAPBI were assessed prospectively for development of pain pretreatment, 1month post-IBAPBI, and every 6months thereafter. A qualitative subjective Late Effects of Normal Tissue-Subjective Objective Management Analytical (LENT-SOMA) questionnaire assessed pain. Use of pain medications was assessed as no, sometimes, or regularly. A quantitative objective validated pressure threshold (PTH) measured pain in the site of IBAPBI breast (index) and its mirror-image in the nonirradiated breast (control). A validated tissue compliance meter (TCM) quantitatively assessed RIF in the index and control breasts at all time points. Mean PTH(kg) and TCM(mm) values reflected mean difference between the index and control breasts. Median follow-up is 44months (range 5-59months). According to LENT-SOMA, pain occurred in 89% at 1 and 24months, 67% at 30months, 30% at 36months, 29% at 40months, and 20% at 48months. No patient used pain medication regularly but the use sometimes decreased over time: 61% at 1month, 42% at 18 and 24months, 13% at 36months, and 10% at 40months. Mean PTH values, compared to 0kg at baseline, peaked in absolute value by 1month to -1.36kg (p<0.0001), persisted after 18months at -0.99kg (p<0.0001) and 24months at -0.73kg (p<0.0001), and returned to nearly baseline by 40months at -0.11kg (p<0.57). Mean PTH and TCM correlated significantly with subjective patient reports of pain at each time point (p<0.0001). To date, this is the first report to prospectively assess pain employing quantitative and qualitative inventories in patients treated with IBAPBI. Pain is experienced in the majority of patients experienced pain within the first 2years, sometimes requiring a medication, and though subsides, it may persist 4years after IBAPBI.