From the Guidelines
Breast cancer treatment can lead to various complications, including electrolyte abnormalities, and it is crucial to monitor and manage these complications to improve the overall health and quality of life of breast cancer survivors. Common complications include fatigue, pain, lymphedema (swelling in the arm), cardiac toxicity from chemotherapy drugs like doxorubicin and trastuzumab, peripheral neuropathy from taxanes, and bone loss from hormonal therapies such as aromatase inhibitors 1. Surgery may cause infection, seroma formation, or nerve damage. Radiation therapy often causes skin changes, fibrosis, and rarely pneumonitis or cardiac damage.
Key Complications
- Fatigue
- Pain
- Lymphedema
- Cardiac toxicity
- Peripheral neuropathy
- Bone loss Regarding electrolyte abnormalities specifically, chemotherapy agents can cause:
- Hyponatremia
- Hypokalemia
- Hypocalcemia
- Hypomagnesemia Cisplatin commonly causes hypomagnesemia and hypokalemia. Anti-HER2 therapies may lead to diarrhea resulting in electrolyte losses. Vomiting from chemotherapy can cause metabolic alkalosis and hypokalemia. Tumor lysis syndrome, though rare in breast cancer, can cause hyperkalemia, hyperphosphatemia, hypocalcemia, and hyperuricemia. Patients on diuretics for treatment-related edema may develop electrolyte imbalances. Management includes regular monitoring of electrolyte levels during treatment, prompt replacement therapy when abnormalities are detected, and preventive measures such as adequate hydration and antiemetics to reduce vomiting-related electrolyte losses 1.
Management of Complications
- Regular monitoring of electrolyte levels
- Prompt replacement therapy for electrolyte abnormalities
- Preventive measures such as adequate hydration and antiemetics It is essential to note that breast cancer survivors remain at risk indefinitely for complications of their previous cancer treatment, and most also remain at risk indefinitely for local and/or systemic recurrence of their breast cancer 1. Therefore, a comprehensive and holistic approach to breast cancer survivorship care is necessary to improve the overall health and quality of life of breast cancer survivors.
From the FDA Drug Label
OTHER TOXICITIES Vascular toxicities coincident with the use of cisplatin in combination with other antineoplastic agents have been reported. Serum Electrolyte Disturbances Hypomagnesemia, hypocalcemia, hyponatremia, hypokalemia, and hypophosphatemia have been reported to occur in patients treated with cisplatin and are probably related to renal tubular damage. Neurotoxicity, usually characterized by peripheral neuropathies, has been reported Ocular Toxicity Optic neuritis, papilledema, and cerebral blindness have been reported in patients receiving standard recommended doses of cisplatin. Anaphylactic-Like Reactions Anaphylactic-like reactions have been reported in patients previously exposed to cisplatin. Hepatotoxicity Transient elevations of liver enzymes, especially SGOT, as well as bilirubin, have been reported to be associated with cisplatin administration at the recommended doses Myelosuppression occurs in 25% to 30% of patients treated with cisplatin. Gastrointestinal Marked nausea and vomiting occur in almost all patients treated with cisplatin, and may be so severe that the drug must be discontinued.
The complications of breast cancer treatment with cisplatin include:
- Vascular toxicities: myocardial infarction, cerebrovascular accident, thrombotic microangiopathy, cerebral arteritis
- Serum Electrolyte Disturbances:
- Hypomagnesemia
- Hypocalcemia
- Hyponatremia
- Hypokalemia
- Hypophosphatemia
- Neurotoxicity: peripheral neuropathies, loss of taste, seizures, leukoencephalopathy, reversible posterior leukoencephalopathy syndrome (RPLS)
- Ocular Toxicity: optic neuritis, papilledema, cerebral blindness, blurred vision, altered color perception
- Anaphylactic-Like Reactions: facial edema, wheezing, tachycardia, hypotension
- Hepatotoxicity: transient elevations of liver enzymes, bilirubin
- Myelosuppression: leukopenia, thrombocytopenia, anemia
- Gastrointestinal: marked nausea and vomiting, diarrhea 2 2
From the Research
Complications of Breast Cancer Treatment
The treatment of breast cancer can lead to various complications, including:
- Electrolyte abnormalities, such as hypomagnesemia and hypokalemia, which can occur due to certain chemotherapies, including cisplatin, cetuximab, eribulin, and ifosfamide 3
- Fluid and electrolyte disturbances, such as water excess, decreased vascular volume, hypercalcemia, hypokalemia, and tumor lysis syndrome, which can be life-threatening if not properly managed 4
- Electrolyte disorders, including sodium disorders, potassium disorders, and abnormalities in magnesium, calcium, and phosphorus levels, which can have significant impacts on treatment outcomes and quality of life 5
Electrolyte Abnormalities
Electrolyte abnormalities can occur in cancer patients due to various factors, including:
- Cancer-specific therapies, such as surgical and radiologic therapies, cellular therapies, use of checkpoint inhibitors, and traditional cytotoxic chemotherapy 5
- Spurious electrolyte disorders, which can complicate the interpretation and management of cancer patients, and can lead to unnecessary diagnostic investigations and therapeutic interventions 6
- Unique causes related to the cancer itself or its treatment, such as immune checkpoint inhibitor related hyperkalemia, fibroblast growth factor 23 inhibitor associated hyperphosphatemia, and epidermal growth factor receptor inhibitor associated hypomagnesemia and hypocalcaemia 7
Management of Electrolyte Abnormalities
The management of electrolyte abnormalities in cancer patients is crucial to prevent delays or interruptions in cancer therapy. This can be achieved through:
- Regular electrolyte monitoring and timely intervention 5
- Correct interpretation of laboratory results to avoid spurious electrolyte disorders 6
- Awareness and recognition of electrolyte abnormalities, and knowledge of their causes and management 7
- Provider and patient education to identify and treat electrolyte imbalances in a timely manner 3