Oncotype DX May Not Be Economical for Decisions on Adjuvant Radiation

A part of precision medicine involves using diagnostic tests to guide treatment decisions. Oncology, in particular, is inundated with diagnostic tests; but how valuable are these tests in developing a treatment path, especially considering the complexity of not just tumor types, but also tumor subtypes? Along those lines, a new study in the Journal of Clinical Oncology has concluded that the 21-gene recurrence score test, Oncotype DX, is not cost-effective when choosing to include adjuvant radiation therapy in women with ductal carcinoma in situ (DCIS) who have had breast-conserving surgery.

Oncotype DX, developed for women with early-stage invasive breast cancer, provides a recurrence score based on gene expression in the patient’s breast tumor tissue following surgery. According to the company website, the genes included on the diagnostic have a 2-pronged purpose: to predict disease recurrence and the patient’s response to chemotherapy. For women with the non-invasive form of the disease, ie, DCIS, the test can also predict an ipsilateral (local) recurrence event. Following surgery, women diagnosed with DCIS are usually recommended hormonal therapy or radiation to lower the risk of recurrence or invasive disease. However, guidelines are conflicting on whether women at a ‘low risk’ of recurrence need radiation at all.

In the current study, the authors evaluated the cost-effectiveness of the following strategies for 60-year old women who were divided into 2-cohorts (cohort 1: low/intermediate-grade DCIS, with tumors less than or equal to 2.5 cm; cohort 2: high-grade DCIS with tumors less than or equal to 1 cm):

• No testing, no radiation
• No testing, radiation only for cohort 2
• No radiation for low-grade DCIS, test intermediate- and high-grade DCIS and radiation for intermediate- or high-risk scores
• Test all, but radiation only for intermediate- or high-risk scores
• No testing, radiation for all

Using the standard willingness-to-pay threshold of $100,000 per quality-adjusted-life-year, the authors developed a Markov model using cost and utilities data from literature and Medicare claims. The outcome was to determine the number of women that would need to be irradiated to prevent 1 ipsilateral recurrence event.

The study found that none of the 5 strategies listed above would be cost-effective. Relative to the first strategy, 10.5, 9.1, 7.5, and 13.1 women would need to undergo radiation for strategies 2 to 5, respectively, to prevent 1 ipsilateral recurrence.

The authors conclude that cost-effectiveness of radiation in their study was utility sensitive and recommend that physicians should discuss trade-offs of including radiation or not with their patients to ensure minimal impact on their quality of life.

DCIS affects more than 60,000 women annually in the United States. Despite this large number, optimal treatment and associated risks elude clinicians.

Reference

Raldow AC, Sher D, Chen AB, Recht A, Punglia RS. Cost effectiveness of the Oncotype DX DCIS score for guiding treatment of patients with ductal carcinoma in situ [published online September 12, 2016]. J Clin Oncol. doi: 10.1200/JCO.2016.67.8532.