Since the monoclonal antibody trastuzumab arrived on the scene in the 1990s, the survival rate in patients with the invasive breast cancer type characterized by amplification of the HER2 gene has skyrocketed to 85%. But trastuzumab (also known by the trade name Herceptin) causes cardiac problems for one in four patients. Similarly, heart problems can arise in patients receiving chemotherapies and immunotherapies for other cancer types.
The Johns Hopkins Cardio-Oncology Program works with these patients to keep their risks at bay. Three types of patients find their way to the program, says cardiologist Tala Al-Talib, medical director of Johns Hopkins Heart and Vascular Institute at Green Spring Station.
The first group has severe coronary artery disease or heart failure problems that need to be treated through lifestyle changes and medications in advance of cancer treatments that can sometimes have significant implications for their heart health.
The second group experiences acute issues during therapy. This sometimes lead to delays in cancer treatment that give cardio-oncologists a window in which they can work to keep the heart healthy by maximizing medications or treating cardiac risk factors. The clinical balancing act involved can be more complicated than in the heart-comes-first approach of traditional, stand-alone cardiology.
“Our mentality in cardio-oncology needs to be different,” she says. “Yes, we want to protect the patient’s heart, but we need to focus at the same time on helping the patient make it through their cancer treatment. We want to help them get to that finish line if at all possible.”
Nurse practitioner Kim Cuomo of the Johns Hopkins Heart Failure Bridge Clinic has been working for more than a decade with these patients. “So many of them are so scared,” Cuomo says. “They’re still trying to deal with a cancer diagnosis when all of a sudden this new scary thing comes along.”
The “biggest bucket” of patients land in a third group — long-term cancer survivors. The growing ranks of that group is unquestionably great news, but the news comes with cardiac caveats. One study found that survivors had a 42% higher risk of cardiovascular disease and a 59% higher risk of heart failure compared with patients who had no history of cancer. Survivors of pediatric cancers are seven times more likely to die prematurely from cardiac problems compared with the general population. What causes these elevated risks is not fully elucidated. Clinicians suspect a mix of factors, some brought on by cancers and others by cancer treatments, which can lead to excess inflammation, oxidative stress and other problems.
Cuomo and Al-Talib agree that significant progress has been made in cardio-oncology across all three patient types in recent years, but the field is still young and evolving. Cuomo singles out treatment gains in heart failure issues during cancer treatment as a positive recent development. Al-Talib points to the development of best-practice protocols in screening patients for cardiac issues during trastuzumab therapy.
But the development of such best practices in screening and treatment protocols remain “grey areas” when it comes to follow-up over the longer term, Cuomo says.
Al-Talib gives the hypothetical example of a lymphoma patient who underwent successful treatment 10 years ago. “There’s nothing at this point that tells us exactly how often these survivors should be getting echocardiograms after completion of chemotherapy,” she says. “We recognize that as a big need” going forward. She is looking to close one such knowledge gap in her research, which aims to identify early on which breast cancer survivors are at highest risk of developing cardiac problems later in life, so that they can get earlier and more targeted interventions.
Additional uncertainties in the field abound, thanks in no small part to the appearance in recent years of scores of new chemotherapy drugs and novel immunotherapy strategies. “This is a fast-moving and rapidly changing field,” Cuomo says. “We’re always learning as we go.”
