Accelerated breast radiotherapy may provide a viable treatment option for women diagnosed with DCIS, according to a study published in the July issue of the International Journal of Radiation Oncology. Although the strategy has proven effective among women with invasive breast cancer, the approach had not been verified among women with DCIS.
The incidence of ductal carcinoma in situ (DCIS) swelled from 1.87 per 100,000 in 1973 to 32.5 in 2004. The current treatment standard entails breast-conserving therapy and five to six weeks of adjuvant radiation therapy to the whole breast as well as antihormonal treatment for women with hormone receptor positive tumors. Efforts to determine which women with DCIS can be managed with segmental mastectomy have yielded disappointing results, according to the authors.
“The failure to identify a subset of DCIS carriers that can be ‘safely’ treated by surgery alone sustains the practice of overtreatment of the majority of patients to prevent local recurrence, despite the lack of evidence of an advantage in survival,” wrote Silvia C. Formenti, MD, of the department of radiation oncology at New York University School of Medicine in New York City.
Formenti and colleagues suggested the need to consider accelerated radiotherapy as an option for women with DCIS and designed two trials to study the efficacy of accelerated whole-breast radiotherapy among women with DCIS.
Between 2002 and 2009, the researchers recruited 145 patients (median age, 56 years) to the trials. Fifty-nine women underwent whole breast radiotherapy with a 42 Gy dose in 15 fractions, and 86 women participated in the second trial, which prescribed 40.5 Gy in 15 fractions, with a daily boost of 0.5 Gy to the surgical cavity.
All of the women in the study were alive at a median follow-up of five years. Six patients developed an ipsilateral recurrence; all of these were DCIS and occurred in estrogen positive women. There were three recurrences in each protocol. However, the three women in the boost group were noncompliant with tamoxifen. Three other women developed new contralateral breast cancers.
Cosmesis was self-assessed after a minimum of two years, with 91 percent of women reporting good-excellent and 9 percent reporting fair-poor.
Late toxicity was limited to the skin. Four percent of women had grade 2 fibrosis, 7 percent had grade 2 telangiectasia and 2 percent had grade 3 telangiectasia. Four percent of participants had grade 2 pigmentation changes, 6 percent had grade 2 edema and 4 percent had grade 2 retraction.
Formenti et al concluded, “These preliminary results suggest that DCIS patients can be safely treated with a shorter regimen of radiotherapy.”