What is the association of breast magnetic resonance imaging and a 12-gene expression assay with the treatment of women with ductal carcinoma in situ of the breast who are candidates for breast conservation surgery and radiotherapy?
In this nonrandomized clinical trial of a prespecified primary outcome among 339 women with pure ductal carcinoma in situ, after magnetic resonance imaging, 19% of patients eligible for wide local excision converted to mastectomy; 38% of conversions were based on magnetic resonance imaging findings and 62% on other reasons. Wide local excision was the final surgical procedure in 96% of women who received it as the first procedure after magnetic resonance imaging, and adherence to radiotherapy use guided by a 12-gene assay exceeded 90%.
Breast magnetic resonance imaging and a 12-gene assay may be used to tailor primary surgical treatment and radiotherapy, respectively, and inform patient and physician decision-making to support more targeted therapy.
Advanced diagnostics, such as magnetic resonance imaging (MRI) and gene expression profiles, are potentially useful to guide targeted treatment in patients with ductal carcinoma in situ (DCIS).
To examine the proportion of patients who converted to mastectomy after MRI and the reasons for those conversions and to measure patient adherence to radiotherapy guided by the 12-gene DCIS score.
Design, Setting, and Participants
Analysis of a prospective, cohort, nonrandomized clinical trial that enrolled women with DCIS on core biopsy who were candidates for wide local excision (WLE) from 75 institutions from March 25, 2015, to April 27, 2016, through the Eastern Cooperative Oncology Group–American College of Radiology Imaging Network trial E4112.
Participants underwent breast MRI before surgery, and subsequent management incorporated MRI findings for choice of surgery. The DCIS score was used to guide radiotherapy recommendations among women with DCIS who had WLE as the final procedure and had tumor-free excision margins of 2 mm or greater.
Main Outcomes and Measures
The primary end point was to estimate the conversion rate to mastectomy and the reason for conversion.
Of 339 evaluable women (mean [SD] age, 59.1 [10.1] years; 262 [77.3%] of European descent) eligible for WLE before MRI, 65 (19.2%; 95% CI, 15.3%-23.7%) converted to mastectomy. Of these 65 patients, conversion was based on MRI findings in 25 (38.5%), patient preference in 25 (38.5%), positive margins after attempted WLE in 10 (15.4%), positive genetic test results in 3 (4.6%), and contraindication to radiotherapy in 2 (3.1%). Among the 285 who had WLE performed after MRI as the first surgical procedure, 274 (96.1%) achieved successful breast conservation. Of 171 women eligible for radiotherapy guided by DCIS score (clear margins, absence of invasive disease, and score obtained), the score was low (<39) in 82 (48.0%; 95% CI, 40.6%-55.4%) and intermediate-high (≥39) in 89 (52.0%; 95% CI, 44.6%-59.4%). Of these 171 patients, 159 (93.0%) were adherent with recommendations.
Conclusions and Relevance
Among women with DCIS who were WLE candidates based on conventional imaging, multiple factors were associated with conversion to mastectomy. This study may provide useful preliminary information required for designing a planned randomized clinical trial to determine the effect of MRI and DCIS score on surgical management, radiotherapy, overall resource use, and clinical outcomes, with the ultimate goal of achieving greater therapeutic precision.
ClinicalTrials.gov identifier: NCT02352883
Lehman CD, Gatsonis C, Romanoff J, et al. Association of Magnetic Resonance Imaging and a 12-Gene Expression Assay With Breast Ductal Carcinoma In Situ Treatment. JAMA Oncol. Published online January 17, 20195(7):1036–1042. doi:10.1001/jamaoncol.2018.6269
Customize your JAMA Network experience by selecting one or more topics from the list below.
Create a personal account or sign in to: