Abstract
This multicenter prospective study ( Japanese Radiation Oncology Study Group: JROSG 05-5) aimed to evaluate the effectiveness of postoperative radiotherapy (PORT) in patients with ductal carcinoma in situ (DCIS) with an involved surgical margin or close margin widths of ≤1 mm or less. PORT consisted of whole-breast irradiation (50 Gy in 25 fractions) followed by boost irradiation (10 Gy in 5 fractions). Eligibility criteria were as follows: (i) DCIS without an invasive carcinoma component, (ii) age between 20 and 80 years old, (iii) involved margin or close margin widths of ≤1 mm, (iv) refusal of re-resection, (v) performance status of 0–2, and (vi) written informed consent. The primary endpoint was ipsilateral breast tumor recurrence (IBTR), and secondary endpoints were overall survival (OS), relapse-free survival (RFS), recurrence patterns, and adverse events. A total of 37 patients from 12 institutions were enrolled from January 2007 to May 2009. The median follow-up time was 62 months (range, 28–85 months). The median pathological tumor size was 2.5 cm (range, 0.3–8.5 cm). Of the 37 patients, 21 had involved margins, and 16 had close margins. The 5-year IBTR, OS and RFS rates were 6% (95% confidence interval [CI]: 2–21), 97% (95% CI: 83–99) and 91% (95% CI: 77–97), respectively. Two patients developed local recurrence at the original site after 39 and 58 months. No severe adverse events were found. Our study suggests that this PORT regimen could be a treatment option for patients with DCIS with involved margin or close margin who don't desire re-resection.
Highlights
Ductal carcinoma in situ (DCIS) arising from the breast represents an intraductal epithelial proliferation of malignant cells and is considered to be a non-obligate precursor of invasive cancer [1, 2] Mammography screening programs and high-resolution magnetic resonance imaging have changed the clinical presentation of DCIS [3, 4]
Several randomized clinical trials have demonstrated that postoperative radiotherapy (PORT) after partial resection decreases the risk of ipsilateral breast tumor recurrence (IBTR) [6,7,8,9]
This multicenter prospective study was conducted to evaluate the effectiveness of PORT consisting of tangential whole-breast irradiation (50 Gy in 25 fractions) using photon beams followed by boost irradiation (10 Gy in 5 fractions) of the tumor bed using electron beams for patients with DCIS with an involved surgical margin or close margin widths of ≤1 mm
Summary
Ductal carcinoma in situ (DCIS) arising from the breast represents an intraductal epithelial proliferation of malignant cells and is considered to be a non-obligate precursor of invasive cancer [1, 2] Mammography screening programs and high-resolution magnetic resonance imaging have changed the clinical presentation of DCIS [3, 4]. Several randomized clinical trials have demonstrated that postoperative radiotherapy (PORT) after partial resection decreases the risk of ipsilateral breast tumor recurrence (IBTR) [6,7,8,9]. Breast-conserving therapy, including partial resection followed by PORT, has been one of the current standards of care for DCIS [2, 10, 11]. These randomized trials have mainly included low-risk patients who underwent partial resection and achieved negative surgical margins. There has been little evidence supporting the use of breast-conserving therapy for patients with high-risk DCIS such as those with a positive surgical margin or a narrow distance between surgical margins and tumor cells
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