Efficacy Of Accelerated Partial Breast Irradiation Research Articles

Adjuvant Hypofractionated Whole Breast Irradiation (WBI) vs. Accelerated Partial Breast Irradiation (APBI) in Postmenopausal Women with Early Stage Breast Cancer: 5Years Update of the HYPAB Trial

Therapeutical strategies in breast cancer are continuously updating. Recent researches assessed the possibility of irradiating only the surgical bed in selected patients (Partial Breast Irradiation, PBI). In 2014 we designed a study to evaluate toxicity and cosmesis of APBI using Volumetric Modulated Arc Therapy-Rapid Arc compared with hypofractionated whole breast irradiation (WBI). We present here the 5-years updated data. HYPAB was a single-institution randomized trial that recruited 172 patients from 2015 to 2018. Patients underwent conserving surgery and were randomized to either adjuvant WBI (40.5Gy/15 fractions with simultaneous boost to 48 Gy to tumoral bed) or APBI (30Gy/5 fractions), both delivered with VMAT-RA technique. Clinical evaluation was performed during the first visit, once a week during radiotherapy and during follow up. Cosmesis was assessed using the Harvard Scale for Breast Cosmesis. At the time of the analysis 161 patients were eligible, 53% in the WBI and 47% in the APBI group, with a median follow-up of 67 months. Most common late skin toxicities were G1 fibrosis (32%) and oedema (28%) and were higher in the WBI group; no G3 toxicities were observed. Cosmesis was rated poor in only 6 cases. 147 patients had no evidence of disease at the last follow-up, and no patients died of the disease. Mature results confirm the safety and efficacy of APBI in selected early stage breast cancer patients. Late toxicity is improved in the APBI arm at the cost of a slight increase in local relapse. Further studies are ongoing to better elucidate the use of APBI as a de-escalation approach.

Daily Fractionation of External Beam Accelerated Partial Breast Irradiation to 40 Gy Is Well Tolerated and Locally Effective

Most studies examining accelerated partial breast irradiation (APBI) have used twice-daily fractionation. Cosmesis with this approach has produced mixed results, and the optimal fractionation scheme remains unknown. We sought to evaluate the safety and efficacy of APBI with a total dose of 40Gy in 10 daily fractions. Between 2010 and 2014, we prospectively enrolled 106 patients to receive APBI after lumpectomy for invasive or in situ node-negative breast cancer. Radiation was administered via 3-dimensional conformal techniques. The median age was 62years (range, 39-85), and all patients underwent APBI per protocol. With a median follow-up of 58months, we evaluated patient-reported local toxicity and recurrence outcomes. Of 106 patients, 16 (15%) experienced grade ≥2 skin toxicity. The most common significant toxicities were acute cutaneous changes at 4 to 9weeks after radiation therapy, including grade 2 erythema in 2 patients (1.8%) and skin color changes in 4 patients (3.8%). Only 2 instances of grade 3 toxicity were reported, including 1 patient with acute moist desquamation after radiation therapy and another with fibrosis at 2years. Planning target volume and breast V20 were significantly predictive of skin/subcutaneous toxicity, with evidence that limiting breast V20 to <45% may improve tolerability. Overall, 3 breast cancer recurrences arose: 1 local recurrence in the original quadrant (3years after APBI), 1 in a different ipsilateral quadrant (5years after APBI), and 1 with distant disease 2years after APBI. In an appropriately selected group of patients with early stage breast cancer, APBI to a dose of 40Gy in 10 daily fractions was well tolerated, with most patients (99%) reporting excellent/good cosmesis. Planning target volume and breast V20 should be carefully constrained to limit local morbidity. Longer follow-up will be needed to establish efficacy and subsequent local recurrence rates.

Prospective Analysis of Toxicity in Patients Treated with Strut Adjusted Volume Implant (SAVI) for Early Stage Breast Cancer

Prospective Analysis of Toxicity in Patients Treated with Strut Adjusted Volume Implant (SAVI) for Early Stage Breast Cancer

Propensity-score matched pair comparison of accelerated partial breast irradiation (APBI) and whole breast irradiation (WBI) for ductal carcinoma in situ (DCIS).

1123 Background: DCIS remains a cautionary criterion for APBI by the ASTRO APBI consensus statement. We performed a matched analysis to compare the efficacy of WBI and APBI for patients with DCIS. Methods: Women with DCIS treated with APBI or WBI were reviewed. APBI (n=102) patients with ≥2 y follow-up were matched 1:3 to WBI (n=546) patients with ≥5 y follow-up by age, tumor size, nuclear grade, ER status, margin status, and laterality. Ipsilateral breast tumor recurrence (IBTR), distant metastasis (DM), contralateral breast cancer (CLBC) and cause-specific survival (CSS) were compared by cumulative incidence (Gray’s) and competing risks regression (Fine and Gray’s), and overall survival (OS) and disease-free survival (DFS) by Kaplan-Meier (log-rank test). Results: Median follow-up was 4.6 y (2.0-14.7) for APBI and 9.0 y (5.4-27.0) for WBI. Median (range) or percentages are shown (Table). Patients did not differ by match criteria. There were 17 LR, 1 DM, 19 CLBC, 2 CSS, 22 OS, and 19 DFS events during follow-up. The patient groups had similar rates of cancer-related events including ipsilateral and contralateral breast recurrences at both five and eight years. Treatment type, age, tumor size, nuclear grade, ER status, and hormone therapy (HT) were not prognostic of LR or CLBC on uni- and multi-variate analyses. Conclusions: APBI provides equivalent and exemplary outcomes compared to WBI following breast-conserving surgery for DCIS. These findings support previous reports on the efficacy of APBI in the treatment of noninvasive breast carcinoma. Prospective randomized comparison of APBI to WBI for DCIS is needed. [Table: see text]

Clinical outcomes of patients with tumor bed-to-skin distance (TBS) ≤ 7 mm treated with accelerated partial breast irradiation (APBI) using multilumen catheter.

182 Background: The initial single-lumen Mammosite trial has shown that skin spacing had an important implication on cosmetic outcomes. In this study, we reviewed the patients who were treated with APBI using multilumen catheter and assessed the outcomes for patients with minimal TBS of ≤ 7mm. Methods: Between August 2008 and April 2011, 79 patients were treated with breast-conserving therapy and adjuvant APBI using the Contura Multi-Lumen balloon or strut-adjusted volume implant (SAVI) device. All patients received 3,400 cGy in 10 fractions delivered twice daily using high dose rate radiation with Iridium 192. The dose was prescribed to 1 cm from the applicator surface. Thirty-six patients had a TBS of ≤ 7mm. We analyzed the clinical outcomes according to RTOG 9517 and skin toxicities as per RTOG 9804 in this patient subgroup. Results: The median age was 65 years (range, 50-86 years). All patients had Tis-T1N0 carcinomas; 39% had DCIS and the rest had invasive carcinoma. The majority (92%) were treated with Contura Multi-Lumen balloon and 8% with SAVI. Median follow-up was 18 months (range 6-42 months). The average TBS was 4.8 mm (range 1-7). 21 patients (57%) had a TBS of ≤ 5mm. The median maximal skin dose was 116% (range 82-134%). The median V90, V95 and V100 were 98%, 96% and 92% respectively. The average V150 and V200 were 31.2 and 9.6 cc respectively. At a median of 3 weeks after treatment, 95% of the patients had good to excellent cosmetic outcome. 54% had grade 1, 21% patients had grade 2 skin toxicity and 25% did not have any skin reaction. At last follow-up, 82% of the patients did not have any residual late skin reaction. Grade 1 skin toxicity was reported in 13%, and grade 2 in 1 patient. Cosmesis was excellent in 72% and good in 28% of the patients. There was no loco-regional recurrence. Conclusions: In our patient population, APBI proved to be an effective treatment with a good to excellent cosmetic outcome and acceptable toxicity. Further investigation with larger patient populations and longer follow-up is warranted to confirm the safety and efficacy of APBI for patients with small TBS.

Intraoperative Open-Cavity Implant for Accelerated Partial Breast Irradiation Using High-Dose Rate Multicatheter Brachytherapy in Japanese Breast Cancer Patients: A Single-Institution Registry Study

Background: Previous research has compared the efficacies of accelerated partial breast irradiation (APBI) and wholebreast irradiation (WBI). APBI immediately after surgery may provide more benefit after intraoperative insertion of catheters. Although balloon catheter-based APBI is available in the US, it is difficult in Japanese women, who have relatively small breasts. With the applicators being implanted during tumor removal, APBI can be started immediately after surgery. The aim of this study was to assess the safety and efficacy of APBI using the intraoperative open-cavity implant technique. Method: Patients (age≥40 years) with invasive breast cancer (diameter≤3 cm) were enrolled. Before lumpectomy, the insertion of applicators and delivery doses were simulated by computed tomography (CT). After confirmation of free margins and negative sentinel nodes (SNs) using frozen section analysis, applicators were inserted. Postoperative CT-based dose distribution analysis was performed using dose-volume histograms. APBI was started on the day of surgery, delivering 32 Gy in 8 fractions over the following 5-6 days, and it covered a distance of 2 cm from tumor margins. This observational study was approved by the institutional review board of our hospital. Results: From October 2008 to July 2012, 157 women (160 lesions) were enrolled (age 55.0 years, <40:9, SN+: 25, for patients’ request). The mean number of applicators used was 6.4 (2-15) and mean planning target volume was 35.8 cm3 (6.5-137.1 cm3). All radiotherapy-related toxicities were mild. However, 12 patients (7.5%) experienced wound breakdown because of surgical site infection. Two patients developed ipsilateral breast tumor recurrence (1 marginal, 1 at a distant site). Conclusions: Despite the small number of participants and a short follow-up period, our results suggest that this technique could be helpful in establishing clinical safety and efficacy.