Historically, heart dose from left-sided breast radiotherapy has been associated with a risk of cardiac injury. Data suggests that there is not a threshold for the deleterious effects from radiation on the heart. Over the past several years, advances in radiation delivery techniques have reduced cardiac morbidity due to treatment. Deep inspiration breath hold (DIBH) is a technique that takes advantage of a more favorable position of the heart during inspiration to minimize heart doses over a course of radiation therapy. In the accompanying review article, we outline several methods used to deliver treatment with DIBH, quantify the benefits of DIBH treatment, discuss considerations for patient selection, and identify challenges associated with DIBH techniques.

Current research in radiotherapy (RT) for breast cancer is evaluating neoadjuvant as opposed to adjuvant partial breast irradiation (PBI) with the aim of reducing the volume of breast tissue irradiated and therefore the risk of late treatment-related toxicity. The development of magnetic resonance (MR)-guided RT, including dedicated MR-guided RT systems [hybrid machines combining an MR scanner with a linear accelerator (MR-linac) or 60 Co sources], could potentially reduce the irradiated volume even further by improving tumour visibility before and during each RT treatment. In this position paper, we discuss MR guidance in relation to each step of the breast RT planning and treatment pathway, focusing on the application of MR-guided RT to neoadjuvant PBI.

Purpose NRG Oncology RTOG 1014 is a prospective phase II trial of 3D-CRT PBrI following repeat lumpectomy for in-breast recurrence following previous whole breast irradiation (WBI). The primary goal of the trial was to determine the associated toxicity, tolerance and safety of PBrI. Materials and Methods Eligibility criteria included in-breast recurrence occurring >1 year following WBI, <3cm, unifocal and resected with negative margins. PBrI was targeted to surgical cavity + 1.5 cm; prescription dose of 45 Gy in 1.5Gy BID for 30 treatments was used. The primary objective was to evaluate the rate of grade ≥3 treatment-related skin, fibrosis, and/or breast pain adverse events (AEs), occurring ≤1 year from re-treatment completion. A rate of ≥13% for these AEs in a cohort of 55 patients was determined to be unacceptable, 86% power, 1-sided α=0.07. Results Between 2010 and 2013, 65 patients were accrued and the first 55 eligible and with 1 year follow-up were analyzed. Median age is 68 years. 22 patients had DCIS and 33 invasive disease; 19 ≤1cm, 13 >1 to ≤2cm and 1 >2cm. All patients were clinically node-negative. Systemic therapy was delivered in 51%. All treatment plans underwent quality review for contouring accuracy and dosimetric compliance. All treatment plans scored acceptable for tumor volume (TV) contouring and TV dose volume analysis (DVA). Only 4 (7%) scored unacceptable for organs at risk (OAR) contouring and OAR DVA. Treatment-related skin, fibrosis, and/or breast pain AEs were recorded as grade 1 in 64%, grade 2 in 7% with only 1 (<2%) grade ≥3 and identified as grade 3 fibrosis of deep connective tissue. Conclusion PBrI with 3D-CRT following second lumpectomy for patients experiencing in-breast failures after WBI is safe and feasible with acceptable treatment quality achieved. Skin, fibrosis and breast pain toxicity was acceptable and grade 3 toxicity was rare.

Purpose Radiation dose to the heart correlates with cardiac-related deaths and may partially diminish the benefit of radiation for breast cancer. This study assessed the current nationwide trends in heart-sparing techniques for breast cancer radiation. Methods and Materials In November 2017, an institutional review board–approved survey was sent to radiation oncologists in the United States. Questions assessed demographics and the type and frequency of heart-sparing techniques. Data were analyzed using descriptive statistics and χ 2 tests. Results In total, 530 responses (13%) were obtained. Most physicians had practiced >15 years (46%), with most in a private setting (59%). Eighty-three percent of physicians offered prone positioning and/or deep inspiration breath hold (DIBH). This was more common in academic practice ( P < .01). Seventy-three percent of physicians used heart-sparing techniques for more than three-fourths of left-sided patients. The most commonly used technique was DIBH, and 43% of physicians used the technique more than three-fourths of the time. Commonly used DIBH systems were Varian RPM (54%) and Vision RT/Align RT (31%). No increase in DIBH use was observed with regional nodal irradiation, and coverage of internal mammary chain nodes varied. Patient tolerance (78%) and cardiac-to-chest wall distance (72%) were the most common determinants of DIBH in left-sided patients. Twenty-three percent of physicians used DIBH for right-sided patients, with lung (64%) and heart sparing (46%) as the most common reasons for use. Lack of facilities was the most common reason not to use DIBH (61%). Conclusions Most respondents offer heart-sparing techniques for breast cancer radiation; this is more common in academic centers. DIBH is the most common technique across all practice settings. DIBH is much less commonly used in right-sided patients but is still used by >20% of practitioners, with lung and heart sparing cited as reasons for use. More data are needed to determine if and when this technique should be used in right-sided cases.

IMPORTANCE Mastectomy is standard for recurrence of breast cancer after breast conservation therapy with whole breast irradiation. The emergence of partial breast irradiation led to consideration of its application for reirradiation after a second lumpectomy for treatment of recurrence of breast cancer in the ipsilateral breast.OBJECTIVES To assess the effectiveness and adverse effects of partial breast reirradiation after a second lumpectomy and whether the treatment is an acceptable alternative to mastectomy. DESIGN, SETTING, AND PARTICIPANTSThe NRG Oncology/Radiation Therapy Oncology Group 1014 trial is a phase 2, single-arm, prospective clinical trial of 3-dimensional, conformal, external beam partial breast reirradiation after a second lumpectomy for recurrence of breast cancer in the ipsilateral breast after previous whole breast irradiation. The study opened on June 4, 2010, and closed June 18, 2013. Median follow-up was 5.5 years. This analysis used all data received at NRG Oncology through November 18, 2018. Eligible patients experienced a recurrence of breast tumor that was less than 3 cm and unifocal in the ipsilateral breast more than 1 year after breast-conserving therapy with whole breast irradiation and who had undergone excision with negative margins.INTERVENTIONS Adjuvant partial breast reirradiation, 1.5 Gy twice daily for 30 treatments during 15 days (45 Gy), using a 3-dimensional conformal technique. MAIN OUTCOMES AND MEASURESThe main outcomes of the present study were the predefined secondary study objectives of recurrence of breast cancer in the ipsilateral breast, late adverse events (>1 year after treatment), mastectomy incidence, distant metastasis-free survival, overall survival, and circulating tumor cell incidence.RESULTS A total of 65 women were enrolled, with 58 evaluable for analysis (mean [SD] age, 65.12 [9.95] years; 48 [83%] white). Of the recurrences of breast cancer in the ipsilateral breast, 23 (40%) were noninvasive and 35 (60%) were invasive. In all 58 patients, 53 (91%) had tumors 2 cm or smaller. All tumors were clinically node negative. A total of 44 patients (76%) tested positive for estrogen receptor, 33 (57%) for progesterone receptor, and 10 (17%) for ERBB2 (formerly HER2 or HER2/neu) overexpression. Four patients had breast cancer recurrence, with a 5-year cumulative incidence of 5% (95% CI, 1%-13%). Seven patients underwent ipsilateral mastectomies for a 5-year cumulative incidence of 10% (95% CI, 4%-20%). Both distant metastasis-free survival and overall survival rates were 95% (95% CI, 85%-98%). Four patients (7%) had grade 3 and none had grade 4 or higher late treatment adverse events. CONCLUSIONS AND RELEVANCEFor patients experiencing recurrence of breast cancer in the ipsilateral breast after lumpectomy and whole breast irradiation, a second breast conservation was achievable in 90%, with a low risk of re-recurrence of cancer in the ipsilateral breast using adjuvant partial breast reirradiation. This finding suggests that this treatment approach is an effecti...

Purpose Obesity, as measured by body mass index (BMI), is a risk factor for distant recurrence and decreased survival in breast cancer. We sought to determine whether BMI correlated with local recurrence and reduced survival in a cohort of predominantly obese women treated with breast conservation therapy. Methods and Materials From 1998–2010, 154 women with early stage invasive breast cancer and 39 patients with ductal carcinoma in situ (DCIS) underwent prone whole breast irradiation. Cox proportional hazards regression, Kaplan-Meier methods with log-rank test, and multivariate analysis were used to explore the association of outcomes with BMI. Results The median patient age was 60 years, and the median follow-up was 73 months. The median BMI was 33.2 kg/m2; 91% of patients were overweight (BMI≥25 kg/m2) and 69% of patients were clinically obese (BMI≥30 kg/m2). BMI was significantly associated with local-regional recurrence-free interval for invasive and DCIS patients (hazard ratio 1.09, p=0.047), and there was a trend for increased local-regional recurrence with higher BMI (p=0.09) for patients with invasive disease, which was significant when examining BMI above and below the median value of 33.2 (p=0.008). BMI was also significantly associated with decreased distant recurrence-free interval (DRFI; HR 1.09, p=0.011) and overall survival (OS; HR 1.09, p=0.004); this association remained on multivariate analysis (DRFI, p=0.034; overall survival, p=0.0007). Conclusions These data suggest that BMI may impact the rate of local-regional recurrence in breast cancer patients. Higher BMI predicted worse distant recurrence-free interval and overall survival. This investigation adds to growing evidence that BMI is an important prognostic factor in early stage breast cancer treated with breast conservation therapy.

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