Metastatic Breast Cancer Symptom Management: 5 Things to Know

Kate M. O'Rourke


June 18, 2020

Metastatic breast cancer (MBC) and its treatment cause a wide variety of adverse effects, but in speaking with oncologists who specialize in this disease, they bring to the forefront the most critical symptoms that patients are facing as a result of therapy. Also emerging are a few particularly problematic adverse effects reported by patients with MBC, in addition to their differing priorities and criteria for treatment success across symptoms.

Asked to name five common symptoms of MBC and its treatment, Eric Winer, MD, a medical oncologist at the Dana-Farber Cancer Institute, in Boston, said fatigue and diarrhea are the two adverse events that cut across most treatments. "Side effects are so drug-dependent, but high up on the list is fatigue. Many of these drugs cause fatigue. The other big side effect from a lot of the medicines is diarrhea."

Sara Tolaney, MD, MPH, a medical oncologist also at the Dana-Farber Cancer Institute, remarked, "My top five common symptoms of MBC would be fatigue, neuropathy, neutropenia, nausea, and diarrhea."

Factoring in the perspective of patients with MBC on clinically meaningful symptom improvement and priorities for management will ensure that treatment is consistent with patient values and goals. Here are five things to know about managing symptoms and treatment side effects in MBC.

1. Diarrhea is a frequent problem encountered by patients with MBC and can require admission to the hospital.

Diarrhea is associated with many cancer drugs, such as chemotherapy; HER2-targeted agents; some CDK4/6 inhibitors, such as abemaciclib (Verzenio); and novel antibody-drug conjugates. "Some of the HER2 tyrosine kinase inhibitors, such as neratinib and tucatinib, cause diarrhea, and then in terms of CDK4/6 inhibitors, abemaciclib causes diarrhea," said Tolaney. "Some chemotherapy drugs can also cause diarrhea; capecitabine commonly does, as do some of the novel antibody-drug conjugates, such as sacituzumab govitecan."

Diarrhea from cancer drugs can usually be managed with antidiarrheal agents, such as loperamide (Imodium). Some drugs with very high rates of diarrhea, such as neratinib (Nerlynx), require prophylactic antidiarrheal therapy. "For example, with neratinib, we can use a combination of drugs to stop the diarrhea, such as loperamide plus colestipol," Tolaney commented. "The other thing we use outside of antidiarrheal therapies is dose modification. Sometimes the diarrhea is dose-responsive. We see that particularly with capecitabine, as well as abemaciclib."


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