Margin Status An Indication For Accelerated Partial Breast Irradiation In Early-Stage Breast Cancers

Purpose/Objective(s)We report the five-year data from a single-institution review of women with early-stage breast cancer treated with breast-conservation therapy using accelerated partial breast radiation (APBI).Materials/MethodsAn IRB-approved review of 165 consecutive early-stage breast cancers, treated from 1995-2005 with APBI brachytherapy, reveals 91 cases were treated with interstitial brachytherapy and 74 with balloon brachytherapy. Stage 0, I, or II cancers are eligible for APBI if a <3cm tumor resects with a negative pathologic margin and 0-3 involved nodes. High-dose-rate radiation therapy is delivered twice a day, for five days, to a total dose of 34 Gy. Follow-up at regular intervals documents history, physical examination, and mammography. Physicians use the Harvard scale to grade overall cosmesis, and toxicities, including hyperpigmentation, edema, telangiectasia, pain, surgical defect, fibrosis and fat necrosis, are graded according to the Common Toxicity Criteria for Adverse Events (v3.0). Dose-volume histogram and treatment parameters are collected and analyzed.ResultsMedian follow-up is 59.9 months, with 40% of patients having >70 months follow-up. The median patient age at diagnosis is 70.9 years. Median tumor size is 1.1 cm. The pathologic margin is ≤2 mm in 57 tumors (35%). Tumors are ER+ in 76% of cases. Adjuvant chemotherapy was administered to 13% of patients and 52% received hormone therapy. Locoregional control of disease is achieved in 98.2% of patients. There are three ipsilateral breast tumor recurrences (IBTR), occurring at 50, 81, and 158 months. Overall cosmetic outcome is good/excellent in 90% of patients and fair/poor in 5.4%, 8 patients have no scored cosmesis. There are 7 cases of G3-4 toxicity: 3 with fibrosis and 4 with surgical defects. The most common toxicities are fibrosis G1 (49%), G2 (13%), followed by scarring G1 (37%), G2 (2%), and surgical defects G1 (16%), G2 (6%). With few events, IBTR and cosmesis were not found to have any statistical correlation with the clinical or dosimetric parameters evaluated. Specifically, when the maximum skin dose is <120% of the prescribed dose there was no correlation with skin toxicity.ConclusionsThese excellent local control rates and cosmesis support the continued use of APBI. The ASTRO Consensus guidelines for APBI requires a >2 mm pathologic margin in contrast to the NSABP B-39 criteria of no tumor at the histologic inked margin. Over a third of patients in this series have ≤2 mm of the margin with no increase in IBTR. In this cohort of patients with close margins, brachytherapy delivers substantial dose that achieves local control and spares the morbidity and negative cosmetic impact of additional breast surgery. Purpose/Objective(s)We report the five-year data from a single-institution review of women with early-stage breast cancer treated with breast-conservation therapy using accelerated partial breast radiation (APBI). We report the five-year data from a single-institution review of women with early-stage breast cancer treated with breast-conservation therapy using accelerated partial breast radiation (APBI). Materials/MethodsAn IRB-approved review of 165 consecutive early-stage breast cancers, treated from 1995-2005 with APBI brachytherapy, reveals 91 cases were treated with interstitial brachytherapy and 74 with balloon brachytherapy. Stage 0, I, or II cancers are eligible for APBI if a <3cm tumor resects with a negative pathologic margin and 0-3 involved nodes. High-dose-rate radiation therapy is delivered twice a day, for five days, to a total dose of 34 Gy. Follow-up at regular intervals documents history, physical examination, and mammography. Physicians use the Harvard scale to grade overall cosmesis, and toxicities, including hyperpigmentation, edema, telangiectasia, pain, surgical defect, fibrosis and fat necrosis, are graded according to the Common Toxicity Criteria for Adverse Events (v3.0). Dose-volume histogram and treatment parameters are collected and analyzed. An IRB-approved review of 165 consecutive early-stage breast cancers, treated from 1995-2005 with APBI brachytherapy, reveals 91 cases were treated with interstitial brachytherapy and 74 with balloon brachytherapy. Stage 0, I, or II cancers are eligible for APBI if a <3cm tumor resects with a negative pathologic margin and 0-3 involved nodes. High-dose-rate radiation therapy is delivered twice a day, for five days, to a total dose of 34 Gy. Follow-up at regular intervals documents history, physical examination, and mammography. Physicians use the Harvard scale to grade overall cosmesis, and toxicities, including hyperpigmentation, edema, telangiectasia, pain, surgical defect, fibrosis and fat necrosis, are graded according to the Common Toxicity Criteria for Adverse Events (v3.0). Dose-volume histogram and treatment parameters are collected and analyzed. ResultsMedian follow-up is 59.9 months, with 40% of patients having >70 months follow-up. The median patient age at diagnosis is 70.9 years. Median tumor size is 1.1 cm. The pathologic margin is ≤2 mm in 57 tumors (35%). Tumors are ER+ in 76% of cases. Adjuvant chemotherapy was administered to 13% of patients and 52% received hormone therapy. Locoregional control of disease is achieved in 98.2% of patients. There are three ipsilateral breast tumor recurrences (IBTR), occurring at 50, 81, and 158 months. Overall cosmetic outcome is good/excellent in 90% of patients and fair/poor in 5.4%, 8 patients have no scored cosmesis. There are 7 cases of G3-4 toxicity: 3 with fibrosis and 4 with surgical defects. The most common toxicities are fibrosis G1 (49%), G2 (13%), followed by scarring G1 (37%), G2 (2%), and surgical defects G1 (16%), G2 (6%). With few events, IBTR and cosmesis were not found to have any statistical correlation with the clinical or dosimetric parameters evaluated. Specifically, when the maximum skin dose is <120% of the prescribed dose there was no correlation with skin toxicity. Median follow-up is 59.9 months, with 40% of patients having >70 months follow-up. The median patient age at diagnosis is 70.9 years. Median tumor size is 1.1 cm. The pathologic margin is ≤2 mm in 57 tumors (35%). Tumors are ER+ in 76% of cases. Adjuvant chemotherapy was administered to 13% of patients and 52% received hormone therapy. Locoregional control of disease is achieved in 98.2% of patients. There are three ipsilateral breast tumor recurrences (IBTR), occurring at 50, 81, and 158 months. Overall cosmetic outcome is good/excellent in 90% of patients and fair/poor in 5.4%, 8 patients have no scored cosmesis. There are 7 cases of G3-4 toxicity: 3 with fibrosis and 4 with surgical defects. The most common toxicities are fibrosis G1 (49%), G2 (13%), followed by scarring G1 (37%), G2 (2%), and surgical defects G1 (16%), G2 (6%). With few events, IBTR and cosmesis were not found to have any statistical correlation with the clinical or dosimetric parameters evaluated. Specifically, when the maximum skin dose is <120% of the prescribed dose there was no correlation with skin toxicity. ConclusionsThese excellent local control rates and cosmesis support the continued use of APBI. The ASTRO Consensus guidelines for APBI requires a >2 mm pathologic margin in contrast to the NSABP B-39 criteria of no tumor at the histologic inked margin. Over a third of patients in this series have ≤2 mm of the margin with no increase in IBTR. In this cohort of patients with close margins, brachytherapy delivers substantial dose that achieves local control and spares the morbidity and negative cosmetic impact of additional breast surgery. These excellent local control rates and cosmesis support the continued use of APBI. The ASTRO Consensus guidelines for APBI requires a >2 mm pathologic margin in contrast to the NSABP B-39 criteria of no tumor at the histologic inked margin. Over a third of patients in this series have ≤2 mm of the margin with no increase in IBTR. In this cohort of patients with close margins, brachytherapy delivers substantial dose that achieves local control and spares the morbidity and negative cosmetic impact of additional breast surgery.