"It was overwhelming enough just dealing with cancer treatment, and then they told me to take heart medication too. At first, I couldn't even imagine it. But I gathered my strength when they told me it was essential to endure the chemotherapy schedule and surgery."
Earlier this year at the cardio-oncology clinic at Ewha Womans University Mokdong Hospital, Seo Kyung-ja (pseudonym, 52) clasped the hands of Professor Kim Min-jung of the Department of Cardiology to express her gratitude. Seo had just received a pathologic Complete Response (pCR) determination following four months of chemotherapy and surgery after being diagnosed with breast cancer. pCR indicates a state where no invasive cancer cells are found in the surgically removed breast and lymph node tissue. It serves as an important prognostic indicator for breast cancer patients. Patients who achieve pCR have significantly lower recurrence rates and higher survival rates compared to their original cancer stage.
It was by no means an easy journey. At a relatively young age, Seo had developed problems with her heart valve function and underwent open-heart surgery to replace the damaged valve with an artificial one. Just as she was catching her breath, breast cancer arrived as an unwelcome visitor. Her oncologist explained that if neoadjuvant chemotherapy could shrink the tumor, she could have a partial mastectomy removing only the tumor and surrounding tissue, rather than a total mastectomy. There was no time to delay, and a chemotherapy schedule combining anthracycline-based drugs with trastuzumab-based targeted therapy was arranged. However, the oncologist presented one prerequisite before starting treatment: given that anthracyclines are a representative class of cardiotoxic chemotherapy drugs and she had an underlying condition, she must receive concurrent cardiology care. Seo knocked on the door of the cardio-oncology clinic with some skepticism. After comprehensive evaluation including echocardiography, Professor Kim classified Seo as moderate-to-high risk and initiated intensive management.
Sure enough, within a few months, her whole body began to swell and she developed shortness of breath. "This was a signal that pulmonary edema had developed, with fluid accumulating in the lungs as the pumping function of her heart declined," Professor Kim explained. "I suggested she take additional heart failure medication and see me monthly."
While chemotherapy drugs are powerful weapons that kill cancer cells, certain classes also inflict fatal stress on heart muscle cells. Anthracyclines, commonly used for breast cancer and lymphoma like in Seo's case, are prime examples. According to medical research, patients treated with anthracycline-based chemotherapy have an average three-fold higher risk of developing heart failure compared to the general population who never had cancer. When combined with trastuzumab-based targeted therapy, the risk soars to approximately four to seven times higher. Long-term follow-up studies have also reported that childhood cancer survivors who received chemotherapy face more than 15 times the risk of developing heart failure in adulthood compared to healthy individuals. Patients with underlying conditions are more susceptible to rapid decline in cardiac function or fatal complications such as myocarditis, adverse reactions, and acute coronary syndrome. Many patients cannot complete their planned chemotherapy and must suspend treatment, or suffer irreversible damage to heart muscle, leaving them with lifelong complications like heart failure even after being cured of cancer. This is why close monitoring for cardiac problems is essential from before chemotherapy begins until it ends.
As the chemotherapy schedule continued and the burden on her heart accumulated, an unexpected complication emerged. Seo developed insomnia and heart palpitations that persisted even after sleep. When she came to the clinic for her outpatient visit and described her symptoms, Professor Kim ordered an electrocardiogram that revealed paroxysmal supraventricular tachycardia (PSVT), a type of arrhythmia, was occurring at that very moment. Arrhythmia is a condition that is difficult to diagnose if the moment of occurrence is missed. Immediately after administering an injection, her heart rate stabilized, and Seo overcame another crisis. By visiting the cardio-oncology clinic monthly without fail, separate from her chemotherapy schedule, and communicating closely with the cardiology specialist, Seo completed her entire neoadjuvant chemotherapy schedule without missing a single session. Because the tumor was shrunk before surgery, the surgical extent was also greatly reduced. Seo continues to visit the clinic every three months to monitor her cardiac condition and maintain her healthy daily life.
According to an analysis of cardiovascular disease status among Korean cancer patients by the Korean Society of Cardiology's Cardio-Oncology Research Group, based on National Health Insurance Service big data from 2005 to 2022, cancer-specific mortality decreased by 43% within one year of cancer diagnosis, while cardiovascular mortality hardly decreased at all. With advances in cancer treatment technology, the proportion of deaths from cardiovascular disease rather than cancer itself is increasing. While newly developed ischemic heart disease and stroke among cancer patients decreased by 43% and 39% respectively, heart failure incidence surged by 56%. This is the background behind Ewha Womans University Mokdong Hospital's proactive launch of its cardio-oncology clinic in 2025.
"If heart failure is discovered in a severely deteriorated state during chemotherapy, it takes at least three to four months to recover cardiac function even with the best medications," Professor Kim said. "If systematic cardiovascular disease management is provided from the time of cancer diagnosis, we can prevent the unfortunate situation of having to stop cancer treatment midway."
The ability to provide 'fast-track collaboration' without delay is the cardio-oncology clinic's greatest strength. The European Society of Cardiology's first cardio-oncology guidelines, published in 2022, also include recommendations to "strengthen multidisciplinary communication and minimize unnecessary cancer treatment interruptions."
"Eliminating cancer cells is not all there is to cancer treatment," Professor Kim emphasized. "I will be a steadfast heart guardian so that cancer patients can complete their treatment to the end."
