• To investigate the risk of ipsilateral breast events (IBEs):
  • In patients with DCIS treated with local excision without radiation:
    • The Eastern Cooperative Oncology Group (ECOG) and North Central Cancer Treatment Group:
      • Conducted a prospective trial between 1997 and 2002 known as the E5194 study:
        • Patients were stratified into two groups based on grade:
          • Low- and intermediate-grade DCIS measuring 2.5 cm or smaller, and high-grade DCIS measuring 1 cm or smaller
          • Margin widths of 3 mm or wider were required along with no residual calcifications on postoperative mammograms
        • The low- and intermediate-grade DCIS group:
          • Had a 12-year IBE rate of 14.4%
        • The high-grade group:
          • Had a 12-year IBE rate of 24.6% (p=0.003)
        • Larger tumor size was also found to be statistically significantly associated with developing an IBE (P = .01)
        • The risks of developing an IBE for either DCIS or invasive cancer:
          • Increased over time through 12 years of follow-up, without plateau
• Current literature reports a 50% decrease in local recurrence with radiotherapy after surgical excision of DCIS:
  • However, we continue to look for low risk subsets of patients with DCIS in whom the absolute benefit of radiation therapy of lumpectomy may be small
• The DCIS score (12-gene signature) was developed from tissue samples from the E5194 study:
  • With the goal of identifying low and high-risk subsets of patients with DCIS following lumpectomy alone
  • This assay utilized quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) from tumor specimens from 327 patients with DCIS treated with surgical excision without radiation from the E5194 study:
    • The DCIS score of 0 to 100 (low less than 39, intermediate 39 to 54, high ≥ 55) was then designed to predict the recurrence of IBE overall, as well as DCIS or invasive cancer recurrence:
      • The DCIS score correlated with 10-year IBE risk of:
        • 10.6% in the low-risk group
        • 26.7% in the intermediate-risk group
        • 25.9% in the high-risk group
      • Young age and larger tumor size:
        • Also were found to be independent predictors of recurrence:
          • So, this test may be most beneficial in postmenopausal women with small tumors

References

1. Solin LJ, Gray R, Hughes LL, Wood WC, Lowen MA, Badve SS, et al. Surgical excision without radiation for ductal carcinoma in situ of the breast: 12-year results from the ECOG-ACRIN E5194 Study. J Clin Oncol. 2015;33(33):3938-3944.

2. Solin LJ, Gray R, Baehner FL, Butler SM, Hughes LL, Yoshizawa C, et al. A multigene expression assay to predict local recurrence risk for ductal carcinoma in situ of the breast. J Natl Cancer Inst. 2013;105(10):701-710.