DCIS Score Not Cost-Effective in Selecting Patients for Adjuvant Radiation

For women with ductal carcinoma in situ (DCIS), the use of the Oncotype DX DCIS Score to determine adjuvant treatment strategies for those who undergo breast-conserving surgery is not cost-effective, according to Ann C. Raldow, MD, Harvard Radiation Oncology Program, Boston, MA, and colleagues (Raldow AC, et al. J Clin Oncol. 2016 Sep 12. Epub ahead of print).

Using a Markov model, which assumed that patients were indifferent to whether they had radiation therapy initially, none of the strategies incorporating the use of the DCIS Score were cost-effective for patients who would have been eligible for the Eastern Cooperative Oncology Group (ECOG) E5194 study.

“However, using the DCIS Score reduced the number of women undergoing radiation per IBE [ipsilateral breast event] prevented, thus reducing the proportion of the population exposed to the potential toxicities of RT [radiation therapy]. Whether such a benefit alone is sufficient to justify its increased cost should be openly discussed by all stakeholders,” the investigators reported.

A subset of the genes included in the Oncotype DX test was used to create the DCIS Score. Two studies have demonstrated that the DCIS Score can predict the 10-year risk for IBEs in patients with DCIS who had breast-conserving surgery without adjuvant radiation therapy, “suggesting the potential to use this test to select women who may be treated with surgery alone and omit RT,” Dr Raldow and colleagues noted.

Cost-Effective Analysis

The ECOG E5194 study was a prospective trial of breast-conserving surgery alone for DCIS; the patients were enrolled into 1 of 2 cohorts: low-grade or intermediate-grade DCIS with tumor size ≤2.5 cm (cohort 1), or high-grade DCIS with tumor size ≤1 cm (cohort 2). For the cost-effectiveness analysis, 5 treatment strategies were compared:

• Strategy 1: No patients were tested with the DCIS Score, or given initial radiation therapy
• Strategy 2: No patients were tested, and only patients in cohort 2 received radiation therapy
• Strategy 3: Patients with low-grade DCIS did not have radiation therapy, and those with intermediate-grade or high-grade DCIS were tested. Patients with intermediate-risk or high-risk scores underwent radiation therapy
• Strategy 4: All patients were tested, and those with intermediate-risk or high-risk scores received radiation therapy
• Strategy 5: No patients were tested, and all patients had adjuvant radiation therapy.

Each of the 5 strategies was associated with quality-adjusted life-year gains of 7.46. Mean per-person costs were lowest ($1360) with strategy 1 and highest ($10,969) with strategy 5. Among all of the women, none of the treatment strategies were cost-effective compared with the reference strategy of observation and no radiation therapy, when it was assumed that patients were indifferent to whether they had radiation therapy initially.

Relative to strategy 1, the cost per IBE prevented ranged from approximately $108,000 for strategy 2 to approximately $175,000 for strategies 3 and 4. Relative to strategy 1, the numbers needed to irradiate per IBE prevented were 10.5, 9.1, 7.5, and 13.1 for strategies 2 to 5, respectively.

When examining the incremental cost-effectiveness ratio for each strategy, lowering the utility for a patient who had not received radiation therapy by a small degree (<0.01) below that of a patient who received radiation therapy led to the favoring of strategy 5.

“These results confirm the importance of eliciting patient preferences in decision making when there are multiple reasonable management options,” Dr Raldow and colleagues emphasized.

“In this setting, the benefit of RT depends on the trade-off between the fear and consequences of IBEs (both local recurrence of DCIS or invasive carcinoma) versus the inconvenience, fear, and adverse effects of treatment,” they added.