Based on PubMed | Can heart palpitations occur in advanced-stage endometrial cancer, and what are the common causes and red flags associated with this symptom?

Heart palpitations can occur in people with advanced endometrial cancer, and they often have multiple possible causes related to the cancer itself, its treatments, and common medical issues that arise during care. In many cases, palpitations are benign, but certain warning signs suggest a more serious heart problem that needs urgent evaluation.

Why palpitations can happen

• Cancer treatments (chemo + immunotherapy): Standard regimens for recurrent/metastatic endometrial cancer such as carboplatin and paclitaxel, when combined with immune checkpoint inhibitors (for example, durvalumab or dostarlimab), can affect the heart and thyroid, which may lead to a fast or irregular heartbeat. ^[1] Immune-related heart side effects, while uncommon, can include chest pain, shortness of breath, ankle swelling, and an abnormal heartbeat; these problems may occur within the first 3 months of therapy or even later. ^[1] Immune-related thyroid problems (both underactive and overactive thyroid) are also reported and an overactive thyroid can cause a faster-than-usual heartbeat and heat intolerance, which can feel like palpitations. ^[2]
• Immune-related endocrine effects: Thyroiditis and hyperthyroidism (overactive thyroid) with immune therapy can cause palpitations, sweating, anxiety, and trouble sleeping; routine blood tests are typically done to check thyroid function during these treatments. ^[3] Overactive thyroid specifically can trigger an abnormally fast heartbeat and sensitivity to hot or cold, which users may perceive as pounding or racing heart. ^[2]
• Lung inflammation from immunotherapy: Immune-related lung inflammation can present with shortness of breath, chest pain, fever, and a faster heartbeat, which may accompany palpitations. ^[4]
• General cardiotoxicity risks from oncology care: Some cancer therapies can inflame the heart muscle (myocarditis), disturb heart rhythms (arrhythmias), or reduce heart pumping function; immune therapies are recognized causes of myocarditis and rhythm problems in susceptible individuals. ^[5]
• Anemia from treatment: Chemotherapy can lower red blood cells weeks to months after treatment, leading to dizziness, fatigue, and lightheadedness; the heart may beat faster to compensate, which can be felt as palpitations. ^{[6] [7]}
• Dehydration and electrolyte shifts: Diarrhea from treatment can cause dehydration and lightheadedness; fluid and electrolyte losses can trigger a faster heartbeat and palpitations. ^[6]

Red flags that need urgent care

• Chest pain, shortness of breath, ankle swelling, or an abnormal heartbeat during or after immunotherapy or combined chemo-immunotherapy may signal heart inflammation or dysfunction and should be reported immediately. ^[1]
• New or worsening shortness of breath, chest pain, fever, or a faster-than-normal heartbeat may reflect lung inflammation related to treatment and also warrant prompt evaluation. ^[4]
• Palpitations with dizziness, lightheadedness, fainting, or shortness of breath are concerning features and should be urgently assessed because they can indicate dangerous rhythm problems. ^[8]

Less common but important considerations

• Direct cardiac involvement by cancer: Although rare, endometrial cancer can metastasize to the heart, which may cause breathing problems and potentially rhythm disturbances; early detection can influence treatment options. ^[9]
• Broader cardio-oncology context: People with cancer have a higher likelihood of both rhythm-related and non–rhythm-related causes of palpitations, and evaluation follows similar steps as in the general population with attention to treatment-related nuances. ^[10]

---

Practical next steps if you notice palpitations

• Tell your oncology team promptly if palpitations are new, persistent, or accompanied by red flags. They may recommend an ECG (electrocardiogram), blood tests (including thyroid and electrolytes), and sometimes heart imaging or rhythm monitoring. ^{[1] [3]}
• Track symptoms: Note when palpitations occur, how long they last, associated symptoms (like dizziness or chest pain), and any recent changes in medicines, fluids, or diarrhea. This helps your clinicians pinpoint causes.
• Stay ahead of dehydration: If you have treatment-related diarrhea, seek guidance early uncontrolled diarrhea with dizziness or light-headedness may need urgent care to prevent complications like fast heart rate and electrolyte problems. ^[6]
• Expect routine monitoring: Many treatment plans include periodic checks of thyroid function and, when appropriate, heart function, because catching issues early can prevent serious problems. ^{[3] [1]}

---

At-a-glance summary

Topic	What to know	Why it matters
Immune therapy heart effects	Chest pain, shortness of breath, ankle swelling, abnormal heartbeat can occur during or after treatment	Potentially serious; needs prompt evaluation [1]
Thyroid changes	Overactive thyroid can cause a fast heartbeat, heat intolerance, sweating, anxiety	Common immune-related effect; treatable when identified [2] [3]
Lung inflammation	Shortness of breath, chest pain, fever, faster heartbeat	Can accompany palpitations and needs medical assessment [4]
Anemia	Dizziness, light-headedness, fatigue; can drive a faster heartbeat	Often occurs weeks to months after chemo; treatable (e.g., transfusion) [6] [7]
Dehydration/diarrhea	Dizziness/light-headedness with frequent loose stools; can cause tachycardia	May require urgent fluids and electrolyte correction [6]
Rare cardiac metastasis	Breathing difficulty and possibly rhythm symptoms	Rare but important to recognize in advanced disease [9]
Red flags	Palpitations with chest pain, shortness of breath, fainting, or swelling	Seek urgent care to rule out serious heart or lung issues [1] [4] [8]

---

Bottom line

Heart palpitations can certainly occur in advanced endometrial cancer, often due to treatment-related effects on the heart or thyroid, anemia, dehydration, or less commonly direct heart involvement. Any palpitations with chest pain, shortness of breath, fainting, or leg/ankle swelling should be treated as urgent and evaluated promptly. ^{[1] [4] [8]}