Metastatic Breast Cancer Costs Have Increased, Vary by Subtype

An up-to-date economic evaluation of the costs associated with metastatic breast cancer in the United States revealed significant differences in costs on the basis of cancer subtypes and the increasing availability of novel, often pricier, treatment options.

Overall, researchers found that the mean Medicare costs of anticancer and supportive therapy was highest for hormone receptor (HR)–positive and ERBB2-positive metastatic breast cancer, at nearly $335,000 per person, and lowest for triple-negative metastatic breast cancer at almost $105,000, with annual costs also increasing significantly over time.

“To our knowledge, our study is the first to evaluate the medical cost of treating [metastatic breast cancer] in the US by subtype and therapy line,” the authors reported in research published late last month in JAMA Network Open. “We identified large differences in cost of [metastatic breast cancer] by subtype and years since diagnosis, indicating that these factors should be taken into consideration when evaluating costs associated with treating metastatic breast cancer.”

Breast cancer represents the leading cancer diagnosis among women in the United States, and medical expenditures associated with the disease are the highest among cancer types, with an estimated total spending of $40.6 billion for all privately insured patients in 2018, the authors noted.

However, costs associated specifically with metastatic breast cancer care remain less clear, with wide variations in published reports and a lack of data reflecting more recent treatment advances.

To determine the current treatment sequencing patterns for metastatic breast cancer and associated costs in the US, Natalia Kunst, PhD, of the Department of Health Management and Health Economics, University of Oslo, Norway, and colleagues evaluated data from 15,215 women aged 18 years or older diagnosed with metastatic disease in the nationwide, longitudinal Flatiron Health database from 2011 to 2021.

All participants had at least 6 months of follow-up data, which included receptor status, and at least one documented line of therapy. To determine treatment sequencing patterns, the authors also looked at the most frequently used therapies for up to five lines of sequential therapy.

Patients’ median age was 64; most (64%) were White, almost 12% were African American and 2.4% were Asian. Most had HR-positive, ERBB2-negative metastatic breast cancer (66.9%); followed by HR-positive, ERBB2-positive cancer (18.3%); triple-negative breast cancer (9.6%); and HR-negative, ERBB2-positive cancer (5.3%).

On the basis of publicly available Medicare prices, patients with HR-positive, ERBB2-positive metastatic breast cancer had the highest mean total costs for treatment and supportive care, at $334,812 per patient. For those with HR-negative, ERBB2-positive metastatic breast cancer, the mean costs were $284,609; followed by HR-positive, ERBB2-negative metastatic breast cancer at $104,774, and finally triple-negative breast cancer at $54,355.

The steepest increases in treatment costs over the 10-year study period were observed for HR-positive, ERBB2-negative metastatic breast cancer, rising from $12,986 in 2012 to $80,563 in 2019.

The increases for HR-positive, ERBB2-positive as well as triple-negative breast cancer were notable as well, both rising by about 60% — $99,997-$156,712 for HR-positive, ERBB2-positive cancer and $31,397-$53,775 triple-negative breast cancer.

Key factors behind the cost increases include the availability of novel, more costly therapies over time, such as palbociclib, ribociclib, and abemaciclib for HR-positive disease, and trastuzumab emtansine, neratinib, and tucatinib for ERBB2-positive breast cancer.

Of note, the researchers also observed wide variations in treatment patterns, with the number of unique regimens for each line of therapy ranging between 22 and 105 across the four cancer subtypes.

The authors acknowledged several limitations of the study, such as not accounting for other medical costs, such as surgery, radiation, imaging, and hospital stays.

Importantly, however, the study’s use of patient-level drug cost calculations allowed for direct correlation and stratification by subgroup and line number.
“Our study provides greater clarity around the cost breakdown of anticancer and supportive care treatment for metastatic breast cancer by subgroup, as well as the most common treatment sequences across the first 5 lines of therapy,” the authors concluded.

As the authors observed, treatment variation is highly common. A recent analysis from the Surveillance, Epidemiology and End Results (SEER)–Medicare database identified almost 30000 unique, rare treatment sequences and more than half of patients received a treatment sequence that fewer than 11 other patients received.

Of note, however, another recent study found similar outcomes among patients with endocrine-refractory or triple-negative breast cancer regardless of therapy sequencing, suggesting that treatment decisions can safely consider costs without affecting clinical outcomes.

“Our results may help improve the evaluation of metastatic breast cancer treatments in the US when considering both effects and costs and emphasize the importance of considering receptor type and time since diagnosis in the evaluation,” the authors concluded.

Kunst had no disclosures to report. The co-authors’ disclosures are detailed in the published study.

JAMA Netw Open. Published online November 29, 2022. Full text

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