The risk of recurrence continues to rise for at least 12 years among patients with low-risk DCIS who forgo radiotherapy after undergoing lumpectomy, investigators reported online Sept. 14 in Journal of Clinical Oncology.
These investigators performed an extended follow-up of 665 patients who participated in an Eastern Cooperative Oncology Group–American College of Radiology Imaging Network nonrandomized trial in 1997-2002. All the participants had either a single low- or intermediate-grade tumor sized 2.5 cm or smaller (cohort 1, 561 patients) or a high-grade tumor 1 cm or smaller (cohort 2, 104 patients), and lumpectomy without radiotherapy was considered a reasonable treatment option for all based on favorable clinical and pathological characteristics. The median patient age was 59 years, and 30% of the study population received tamoxifen during follow-up, said Dr. Lawrence J. Solin of Albert Einstein Healthcare Network, Philadelphia, and his associates.
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Histopathologic image from DCIS of breast. Hematoxylin-eosin stain.
During a median of 12.3 years of follow-up, there were 99 recurrences: 48 cases of DCIS and 51 cases of invasive cancer in the ipsilateral breast. The 12-year rates of developing any recurrence were 14.4% in cohort 1 and 24.6% in cohort 2, and the 12-year rates of developing an invasive cancer were 7.5% and 13.4%, respectively. Most important, the risk of any recurrence increased steadily over time, without any plateau, the investigators said (J Clin Oncol. 2015 Sep 14. doi: 10.1200/JCO.2015.60.8588).
“Individual patients and their physicians will need to decide if these 12-year risks are acceptable, and whether or not to forgo adding adjuvant treatment after surgical excision,” Dr. Solin and his associates said.
Most of the study participants were postmenopausal and had small, asymptomatic microcalcifications detected on routine screening mammography; most also had negative margins at resection. Since these traits are similar to those of patients with DCIS in population-based studies, the findings of this trial are relevant to contemporary practice, the researchers added.
“Not all patients and their physicians will agree on what is considered too high a risk of developing [a recurrence] or [an invasive recurrence] to recommend observation after surgical excision, or what risk is considered too low to justify adding radiation treatment. However, this study provides 12-year data to begin those discussions, and to help inform the treatment decision-making process,” Dr. Solin and his associates said.