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, 1 month post-IBAPBI, and every 6 months 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 ΔPTH(kg) and ΔTCM(mm) values reflected mean difference between the index and control breasts. Median follow-up is 44 months (range 5-59 months). According to LENT-SOMA, pain occurred in 89% at 1 and 24 months, 67% at 30 months, 30% at 36 months, 29% at 40 months, and 20% at 48 months. No patient used pain medication "regularly" but the use "sometimes" decreased over time: 61% at 1 month, 42% at 18 and 24 months, 13% at 36 months, and 10% at 40 months. Mean ΔPTH values, compared to Δ0 kg at baseline, peaked in absolute value by 1 month to -1.36 kg (p < 0.0001), persisted after 18 months at -0.99 kg (p < 0.0001) and 24 months at -0.73 kg (p < 0.0001), and returned to nearly baseline by 40 months at -0.11 kg (p < 0.57). Mean ΔPTH and ΔTCM 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 2 years, sometimes requiring a medication, and though subsides, it may persist 4 years after IBAPBI.