Cardiac monitoring may benefit in high-risk breast cancer

HF is an uncommon complication of breast cancer treatment, but cardiac monitoring should be conducted in certain high-risk patients, according to a study published in JACC: Cardiovascular Imaging.

Risk for HF was highest in older patients and in those treated with trastuzumab (Herceptin, Genentech) or anthracyclines, according to the researchers.

“We must remember that while cardiac monitoring is recommended in different guidelines, recommendations are not made based on category 1 data, and the intervals of testing are rather arbitrary,” Mariana L. Henry, BS, a graduate student at Yale School of Public Health, said in a press release. “In examining the rate of both cardiac monitoring and cardiotoxicity, we could begin to address the controversial issue of whether cardiac monitoring is warranted in young breast cancer patients.”

Henry and colleagues analyzed 16,456 adult patients (median age, 56 years) diagnosed with nonmetastatic invasive breast cancer between 2009 and 2014 and treated with chemotherapy within 6 months of their diagnosis.

Using diagnosis and billing codes, the researchers stratified patients by diagnosis of HF, comorbidities and types of treatment for breast cancer.

Predictors of cardiotoxicity

Cardiotoxicity, defined as incident HF after breast cancer diagnosis, occurred in 4.2% of patients, according to the researchers.

Henry and colleagues identified the following factors as predictors of cardiotoxicity:

treatment with trastuzumab (HR = 2.01; 95% CI, 1.72-2.36);
treatment with anthracyclines (HR = 1.53; 95% CI, 1.3-1.8);
Deyo comorbidity score (HR for score of 1 = 1.38; 95% CI, 1.15-1.66; HR for score of 2 or more = 2.47; 95% CI, 1.94-3.15);
hypertension (HR = 1.28; 95% CI, 1.09-1.51); and
·valve disease (HR = 1.93; 95% CI, 1.48-2.51).

Compared with patients aged at least 65 years, patients aged 35 years or younger (HR = 0.37; 95% CI, 0.19-0.72) and patients aged 36 to 49 years (HR = 0.49; 95% CI, 0.38-0.62) were less likely to have cardiotoxicity.

“HF was more frequently identified among patients undergoing recommended cardiac monitoring (10.4% compared with 6.5%, respectively; P < .001), suggesting that, as more patients are screened, more patients are likely to be found having HF,” Henry and colleagues wrote.

Of the 4,325 patients treated with trastuzumab, 73.5% had cardiac monitoring at baseline and 46.2% had guideline-adherent cardiac monitoring, according to the researchers.

Increased odds of receiving guideline-adherent cardiac monitoring occurred in patients treated with anthracyclines (OR = 1.58; 95% CI, 1.38-1.87), patients treated with taxanes (OR = 1.63; 95% CI, 1.27-2.08), patients treated with radiation (OR = 1.22; 95% CI, 1.08-1.39), patients diagnosed more recently (OR for 2014 vs. 2009 = 1.4; 95% CI, 1.11-1.76) and patients with insurance other than HMO or preferred provider organization (OR for other vs. PPO = 1.16; 95% CI, 1.01-1.34).

“Our study demonstrates that cancer treatment history and comorbidities are important risk factors for cardiotoxicity,” Henry and colleagues wrote. “Biomarkers may be promising and cost-effective in the prediction of cardiotoxicity compared to cardiac monitoring. The number of cancer survivors is expected to increase over time, and we will continue to see patients develop treatment-related cardiotoxicity. Thus, more research, evidence-based guidelines, and tools for prediction of cancer treatment-related cardiotoxicity are needed.”

Need for monitoring

“The adherence rate of approximately 46% in this study was slightly higher than the rate of 36% reported in a previous study in older patients but still not high, nevertheless,” Chau T. Dang, MD, from the department of medicine at Memorial Sloan Kettering Cancer Center, and colleagues wrote in a related editorial. “Thus, why was adherence low in the overall study? Authors offered one explanation, which was the possibility that the need for routine monitoring was perceived as low by clinicians. However, one must ask if there are sufficient data to demonstrate that adherence to cardiovascular monitoring guidelines is associated with better outcomes and if these guidelines are still relevant today.” – by Erik Swain

Disclosure: Henry reports no relevant financial disclosures. Dang reports she received institutional research funding from Roche/Genentech and PUMA. Please see the study and editorial for the other authors’ relevant financial disclosures.

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Sources/Disclosures

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Source:

Dang CT, et al. JACC Cardiovasc Imaging. 2018;doi:10.1016/j.jcmg.2018.02.027.

Henry ML, et al. JACC Cardiovasc Imaging. 2018;doi:10.1016/j.jcmg.2018.06.005.