A prospective study of the utility of magnetic resonance imaging in determining candidacy for partial breast irradiation

The Role of MRI in Breast Cancer and Breast Conservation Therapy

Contrast-enhanced breast MRI has an established role in aiding in the detection, evaluation, and management of breast cancer. This article discusses MRI sequences, the clinical utility of MRI, and how MRI has been evaluated for use in breast radiotherapy treatment planning. We highlight the contribution of MRI in the decision-making regarding selecting appropriate candidates for breast conservation therapy and review the emerging role of MRI-guided breast radiotherapy.

Partial Breast Irradiation for Patients With Early-Stage Invasive Breast Cancer or Ductal Carcinoma In Situ: An ASTRO Clinical Practice Guideline

PURPOSE

This guideline provides evidence-based recommendations on appropriate indications and techniques for partial breast irradiation (PBI) for patients with early-stage invasive breast cancer and ductal carcinoma in situ.

METHODS

ASTRO convened a task force to address 4 key questions focused on the appropriate indications and techniques for PBI as an alternative to whole breast irradiation (WBI) to result in similar rates of ipsilateral breast recurrence (IBR) and toxicity outcomes. Also addressed were aspects related to the technical delivery of PBI, including dose-fractionation regimens, target volumes, and treatment parameters for different PBI techniques. The guideline is based on a systematic review provided by the Agency for Healthcare Research and Quality. Recommendations were created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

PBI delivered using 3-dimensional conformal radiation therapy, intensity modulated radiation therapy, multicatheter brachytherapy, and single-entry brachytherapy results in similar IBR as WBI with long-term follow-up. Some patient characteristics and tumor features were underrepresented in the randomized controlled trials, making it difficult to fully define IBR risks for patients with these features. Appropriate dose-fractionation regimens, target volume delineation, and treatment planning parameters for delivery of PBI are outlined. Intraoperative radiation therapy alone is associated with a higher IBR rate compared with WBI. A daily or every-other-day external beam PBI regimen is preferred over twice-daily regimens due to late toxicity concerns.

CONCLUSIONS

Based on published data, the ASTRO task force has proposed recommendations to inform best clinical practices on the use of PBI.

Multidisciplinary care of breast cancer patients: a scoping review of multidisciplinary styles, processes, and outcomes

Background

Clinical practice guidelines recommend a multidisciplinary approach to cancer care that brings together all relevant disciplines to discuss optimal disease management. However, the literature is characterized by heterogeneous definitions and few reviews about the processes and outcomes of multidisciplinary care. The objective of this scoping review was to identify and classify the definitions and characteristics of multidisciplinary care, as well as outcomes and interventions for patients with breast cancer.

Methods

A systematic search for quantitative and qualitative studies about multidisciplinary care for patients with breast cancer was conducted for January 2001 to December 2017 in the following electronic databases: medline, embase, PsycInfo, and cinahl. Two reviewers independently applied our eligibility criteria at level 1 (title/abstract) and level 2 (full-text) screening. Data were extracted and synthesized descriptively.

Results

The search yielded 9537 unique results, of which 191 were included in the final analysis. Two main types of multidisciplinary care were identified: conferences and clinics. Most studies focused on outcomes of multidisciplinary care that could be variously grouped at the patient, provider, and system levels. Research into processes tended to focus on processes that facilitate implementation: team-working, meeting logistics, infrastructure, quality audit, and barriers and facilitators.

Summary

Approaches to multidisciplinary care using conferences and clinics are well described. However, studies vary by design, clinical context, patient population, and study outcome. The heterogeneity of the literature, including the patient populations studied, warrants further specification of multidisciplinary care practice and systematic reviews of the processes or contexts that make the implementation and operation of multidisciplinary care effective.

How Does MR Imaging Help Care for My Breast Cancer Patient? Perspective of a Radiation Oncologist

Radiation therapy is used in many cases of both early and late breast cancer. The authors examine the role of MR imaging as it pertains to radiotherapy planning and treatment approaches for patients with breast cancer. MR imaging can assist the radiation oncologist in determining the best radiation approach and in creating treatment planning volumes. MR imaging may be useful in the setting of accelerated partial breast irradiation. Radiation oncologists should attend to MR breast images, when obtained, to ensure that these imaging findings are taken into consideration when developing a radiation therapy plan.

MR Imaging for Selection of Patients for Partial Breast Irradiation: A Systematic Review and Meta-Analysis

PURPOSE

To systematically review articles that estimated the ineligibility for partial breast irradiation (PBI) after magnetic resonance (MR) imaging.

MATERIALS AND METHODS

No ethics committee approval was needed. A systematic search was performed by using MEDLINE and EMBASE. The rate of patients eligible at standard assessment (ie, clinical examination, mammography, and/or ultrasonography) but ineligible after MR imaging was a study outcome. Odds ratios (ORs) were calculated to identify predictors. Quality was appraised by using the Strengthening Reporting of Observational Studies in Epidemiology checklist.

RESULTS

Of 93 retrieved articles, six were included (total, 3136 patients). For PBI eligibility, all studies applied National Surgical Adjuvant Breast and Bowel Project B-39 criteria. Ineligibility at standard assessment varied from 21% to 80%; MR imaging prompted ineligibility for PBI in 6%-25% of patients who were initially deemed eligible or in 2%-20% if calculated on the overall number of patients initially screened. Meta-regression showed a negative correlation between ineligibility at standard assessment and ineligibility after MR imaging (P < .001). The pooled percentage of patients eligible at standard assessment but ineligible after MR imaging was 11% (95% confidence interval [CI]: 6%, 19%). Predictors for ineligibility after MR imaging were cancers stage pT2 or greater versus less than stage pT2 (OR, 8.8 [95% CI: 4.7, 16.7]; P < .001), invasive lobular histopathologic results versus invasive ductal pathologic results (OR, 3.0 [95% CI: 1.6, 6.6]; P = .007), pre- versus postmenopausal status (OR, 1.9 [95% CI: 1.3, 2.6]; P < .001), invasive cancer versus ductal carcinoma in situ (OR, 1.6 [95% CI: 1.0, 2.4]; P = .031). Study quality ranged from 17 to 20 (maximum quality, 22). The risk of publication bias was moderate.

CONCLUSION

One of nine women (11%), who on the sole basis of standard assessment were candidates to undergo PBI, was found to be ineligible after undergoing MR imaging. Breast MR imaging should be used to select patients for PBI.

Current clinical indications for magnetic resonance imaging of the breast

MRI is increasingly used in breast cancer patients. MRI has a high sensitivity compared to mammography and ultrasound. The specificity is moderate leading to an increased risk of false positive findings. Currently, a beneficial effect of breast MRI has been established in some patient groups and is debated in the general breast cancer population. The diagnostic ability of MRI and its role in various groups of breast cancer patients are discussed in this review.

Applications for breast magnetic resonance imaging

This article reviews the relevant data on breast magnetic resonance imaging (MRI) use in screening, the short-term surgical outcomes and long-term cancer outcomes associated with the use of MRI in breast cancer staging, the use of MRI in occult primary breast cancer, as well as MRI to assess eligibility for accelerated partial breast irradiation and to evaluate tumor response after neoadjuvant chemotherapy. MRI for screening is supported in specific high-risk populations, namely, women with BRCA1 or BRCA2 mutations, a family history suggesting a hereditary breast cancer syndrome, or a history of chest wall radiation.

Evaluation of expert criteria for preoperative magnetic resonance imaging of newly diagnosed breast cancer

Despite 2 randomized trials reporting no reduction in operations or local recurrence at 1 year, preoperative magnetic resonance imaging (MRI) is increasingly used in diagnostic workup of breast cancer. We evaluated 5 utilization criteria recently proposed by experts. Of women (n = 340) newly diagnosed with unilateral breast cancer who underwent bilateral MRI, most (69.4%) met at least 1 criterion before MRI: mammographic density (44.4%), under consideration for partial breast irradiation (PBI) (19.7%), genetic-familial risk (12.9%), invasive lobular carcinoma (11.8%), and multifocal/multicentric disease (10.6%). MRI detected occult malignant lesion or extension of index lesion in 21.2% of index, 3.3% of contralateral, breasts. No expert criterion was associated with MRI-detected malignant lesion, which associated instead with pre-MRI plan of lumpectomy without PBI (48.2% of subjects): Odds Ratio 3.05, 95% CI 1.57-5.91 (p adjusted for multiple hypothesis testing = 0.007, adjusted for index-vs-contralateral breast and covariates). The expert guidelines were not confirmed by clinical evidence.

Usefulness of magnetic resonance in patients with invasive cancer eligible for breast conservation: a comparative study

BACKGROUND

The role of magnetic resonance imaging (MRI) in newly detected breast cancer remains controversial. We investigated the impact of preoperative MRI on surgical management of infiltrating breast carcinoma (IBC).

METHODS

We reviewed data of 237 patients with IBC who were suitable for breast-conserving surgery (BCS) between 2009 and 2011. Of these patients, 109 underwent preoperative MRI (46%; MRI group) and 128 did not (54%; no-MRI group). We analyzed MRI-triggered changes in surgical plan and compared differences in rates of positive margins and mastectomy.

RESULTS

Tumor size was larger in the MRI group (16.8 mm vs. 13.9 mm; P < .001). MRI changed the initial surgical planning in 18 of 109 patients (16.5%) because of detection of larger tumor diameter requiring wider resection (8 patients [7.3%]) or additional malignant lesions in the ipsilateral (9 patients [8.2%]) or contralateral breast (1 patient [0.9%]). MRI-triggered treatment changes included mastectomy (n = 12), wider excision (n = 5), and contralateral BCS (n = 1). Reoperation rates for positive margins after BCS appeared higher in the no-MRI group (4.1% vs. 8.6%), but the difference missed statistical significance (P = .9). Overall mastectomy rates were higher in the MRI group (13.7% vs. 7.0%; P < .05). The likelihood of having a change of treatment resulting from MRI was significantly higher for patients with tumors > 15 mm and for those with positive lymph nodes.

CONCLUSION

Lymph node positivity and tumor size > 15 mm may predict an MRI-triggered change in surgical plan. Preoperative MRI resulted in higher mastectomy rates justified by biopsy-proven additional foci of carcinoma and did not significantly reduce reoperation rates for positive margins.

Classification system for identifying women at risk for altered partial breast irradiation recommendations after breast magnetic resonance imaging

PURPOSE

To study the utility of preoperative breast MRI for partial breast irradiation (PBI) patient selection, using multivariable analysis of significant risk factors to create a classification rule.

METHODS AND MATERIALS

Between 2002 and 2009, 712 women with newly diagnosed breast cancer underwent preoperative bilateral breast MRI at Mayo Clinic Florida. Of this cohort, 566 were retrospectively deemed eligible for PBI according to the National Surgical Adjuvant Breast and Bowel Project Protocol B-39 inclusion criteria using physical examination, mammogram, and/or ultrasound. Magnetic resonance images were then reviewed to determine their impact on patient eligibility. The patient and tumor characteristics were evaluated to determine risk factors for altered PBI eligibility after MRI and to create a classification rule.

RESULTS

Of the 566 patients initially eligible for PBI, 141 (25%) were found ineligible because of pathologically proven MRI findings. Magnetic resonance imaging detected additional ipsilateral breast cancer in 118 (21%). Of these, 62 (11%) had more extensive disease than originally noted before MRI, and 64 (11%) had multicentric disease. Contralateral breast cancer was detected in 28 (5%). Four characteristics were found to be significantly associated with PBI ineligibility after MRI on multivariable analysis: premenopausal status (P=.021), detection by palpation (P<.001), first-degree relative with a history of breast cancer (P=.033), and lobular histology (P=.002). Risk factors were assigned a score of 0-2. The risk of altered PBI eligibility from MRI based on number of risk factors was 0:18%; 1:22%; 2:42%; 3:65%.

CONCLUSIONS

Preoperative bilateral breast MRI altered the PBI recommendations for 25% of women. Women who may undergo PBI should be considered for breast MRI, especially those with lobular histology or with 2 or more of the following risk factors: premenopausal, detection by palpation, and first-degree relative with a history of breast cancer.

Four-year clinical update from a prospective trial of accelerated partial breast intensity-modulated radiotherapy (APBIMRT)

This prospective Phase II single-arm study gathered data on the use of intensity-modulated radiotherapy (IMRT) to deliver accelerated partial breast irradiation (APBI). Four-year efficacy, cosmesis, and toxicity results are presented. Between February 2004 and September 2007, 136 consecutive patients with Stage 0/I breast cancer and negative margins ≥0.2 cm were treated on protocol. Patients received 38.5 Gy in 10 equal fractions delivered twice daily. Breast pain and cosmesis were rated by patient, and cosmesis was additionally evaluated by physician per Radiation Therapy Oncology Group (RTOG) criteria. The National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE v3.0) was used to grade toxicities. 136 patients (140 breasts) with median follow-up of 53.1 months (range, 8.9-83.2) were evaluated. Population characteristics included median age of 61.9 years and Tis (13.6 %), T1a (18.6 %), T1b (36.4 %), and T1c (31.4 %). Kaplan-Meier estimates at 4 years: ipsilateral breast tumor recurrence 0.7 %; contralateral breast failure 0 %; distant failure 0.9 %; overall survival 96.8 %; and cancer-specific survival 100 %. At last follow-up, patients and physicians rated cosmesis as excellent/good in 88.2 and 90.5 %, respectively; patients rated breast pain as none/mild in 97.0 %. Other observations included edema (1.4 %), telangiectasia (3.6 %), five cases of grade 1 radiation recall (3.6 %), and two cases of rib fractures (1.4 %). This analysis represents the largest cohort and longest follow-up of APBI utilizing IMRT reported to date. Four-year results continue to demonstrate excellent local control, survival, cosmetic results, and toxicity profile.