Patient preferences regarding intraoperative versus external beam radiotherapy following breast-conserving surgery

Abstract

The TARGIT-A Trial is an international randomized, prospective trial comparing intraoperative radiotherapy (IORT) for equivalence to external beam radiotherapy (EBRT) following lumpectomy for invasive breast cancer in selected low-risk patients; early results suggest that outcomes are similar. In addition to effectiveness data and cost considerations, the preferences of patients should help inform practice. This study was undertaken to explore and quantify preference in choosing between IORT and the current standard, EBRT. Eligible subjects were current or past candidates for breast-conserving surgery and radiation being seen at the University of California, San Francisco Breast Care Center. A trade-off technique varying the risk of local recurrence for IORT was used to quantify any additional accepted risk that these patients would accept to receive either treatment. Patients were first presented with a slideshow comparing EBRT with the experimental IORT option before being asked their preferences given hypothetical 10-year local recurrence risks. Patients were then given a questionnaire on demographic, social and clinical factors. Data from 81 patients were analyzed. The median additional accepted risk to have IORT was 2.3 % (-9 to 39 %), mean 3.2 %. Only 7 patients chose to accept additional risk for EBRT; 22 accepted IORT at no additional risk; and the remaining 52 chose IORT with some additional risk. Patients weigh trade-offs of risks and benefits when presented with medical treatment choices. Our results show that the majority of breast cancer patients will accept a small increment of local risk for a simpler delivery of radiation. Further studies that incorporate outcome and side effect data from the TARGIT-A trial clarify the expected consequences of a local recurrence, and include an expanded range of radiation options that could help guide clinical decision making in this area.

An international randomised controlled trial to compare TARGeted Intraoperative radioTherapy (TARGIT) with conventional postoperative radiotherapy after breast-conserving surgery for women with early-stage breast cancer (the TARGIT-A trial)

“…101,103,104 It is much smaller than the 7.5% margin in the ELIOT trial 105 and lower than the difference considered 'acceptable' by the CALGB (5% difference) 11 and Post-operative Radiotherapy In Minimum-risk Elderly (PRIME) II (3% difference) 106 studies. At this boundary, TARGIT was non-inferior to EBRT (P non-inferiority < 0.00001).…”

“…The pre-specified non-inferiority boundary of a 2.5% absolute difference in local recurrence is very conservative and has been validated in patient preference studies. 101,103,104 At this boundary, TARGIT is non-inferior to EBRT (P non-inferiority < 0.00001) ( Figure 38). Furthermore, we have recommended that TARGIT should be used during the initial lumpectomy, as in the prepathology stratum (note that this is a stratum not a subgroup), when the difference between the two treatments was undoubtedly not statistically significant (p = 0.31).…”

“…We suggest that given a choice women happily opt for TARGIT to avoid several weeks of daily attendance at the radiotherapy centre or, in resource-poor parts of the world, the threat of a mastectomy. 22,100,101,103,104,114,115 From a patient's perspective, the most important benefit of TARGIT for a woman with breast cancer is that it allows her to complete her entire local treatment (lumpectomy and radiation therapy) at the time of her operation, with lower toxicity. Therefore, the use of TARGIT in relatively mobile patients in the most developed and well-resourced communities would avoid the inconvenience and cost of this prolonged daily radiation course whereas others, who may have been obliged to choose a mastectomy, can avail themselves of breast-conserving therapy.…”

The INTRABEAM® Photon Radiotherapy System for the adjuvant treatment of early breast cancer: a systematic review and economic evaluation

“…64 However, it should be noted that, when the non-inferiority margin was chosen, the estimated local recurrence rate (LRR) (based on the literature available in 1999) 70,71 was 6%, and since then recurrence rates have fallen. Two patient preference studies 72,73 suggest that patients would be willing to accept an increase in the risk of local recurrence for the convenience of INTRABEAM treatment but it should be noted that these studies were conducted in countries in which WB-EBRT is typically delivered over 5-6 weeks and it is not known whether or not patient preference would be similar in England where WB-EBRT is typically delivered over 3 weeks.…”

Techniques for Intraoperative Radiation Therapy for Early-Stage Breast Carcinoma

“…A quality-oflife study of 87 women included on the TARGIT study demonstrated less pain and improved functioning in patients receiving IORT over WBI [64]. In a survey of patients previously treated with BCT, Alvarado et al demonstrated that 91% of patients surveyed would prefer IORT if IBTR was noninferior and 64% would accept a median 2.3% higher risk for IBTR if it meant simplifying RT with IORT [65]. Therefore, considerations of comparative effectiveness and cost-effectiveness of IORT relative to other adjuvant RT options should encompass the aforementioned additional potential benefits of IORT that are generally not evaluated in clinical trials.…”