High Calcium in Melanoma: Should You Be Concerned?

High calcium (hypercalcemia) can range from mild and harmless to a medical emergency, and in the context of melanoma it deserves prompt attention because cancer can sometimes raise calcium levels. In many cases, hypercalcemia is treatable and can improve quickly with the right care, but it’s important to find the cause and act early. ^{[1] [2]}

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What “High Calcium” Means

• Calcium is tightly regulated by parathyroid hormone (PTH), vitamin D, bones, kidneys, and the gut. When this balance is disrupted, blood calcium rises. ^[3]
• Mild elevations may cause few or no symptoms, while moderate to severe elevations can cause nausea, constipation, confusion, dehydration, abnormal heart rhythms, and kidney strain. Severity and symptoms guide how urgently it must be treated. ^{[4] [1]}

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Why Melanoma Patients May Have High Calcium

There are a few plausible scenarios, and your care team typically checks for all of them:

• Cancer‑related hypercalcemia (paraneoplastic): Some cancers produce substances like PTH‑related peptide (PTHrP) that raise calcium; while this is more classic in certain cancers, melanoma with widespread disease can be associated as well. When hypercalcemia is driven by malignancy, it can worsen as the cancer progresses, so addressing the cancer and the calcium is key. ^{[5] [6]}
• Bone involvement: Cancer that spreads to bone can increase calcium release into the blood; this mechanism is a recognized pathway of cancer‑associated hypercalcemia. Managing bone health and cancer control can help lower calcium. ^[7]
• Primary hyperparathyroidism (non‑cancer cause): A benign parathyroid gland overproducing PTH can raise calcium even in people with cancer; this remains a common cause of hypercalcemia and is treatable, often with surgery. ^[8]
• Vitamin D or supplement excess: Too much vitamin D or calcium from supplements can push calcium high. Stopping or adjusting supplements can normalize levels. ^{[4] [5]}

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What Tests You’ll Likely Need

Your team will aim to confirm the cause because treatment depends on it:

• Repeat serum calcium to confirm the elevation and assess severity. Even mild elevations are rechecked to exclude lab variation. ^[8]
• PTH (parathyroid hormone): High PTH with high calcium suggests primary hyperparathyroidism; low or suppressed PTH suggests a non‑parathyroid cause (often cancer or vitamin D related). This is the key first branch point in diagnosis. ^{[8] [9]}
• PTHrP blood test: Elevated PTHrP with high calcium supports a cancer‑related mechanism. This helps distinguish paraneoplastic hypercalcemia. ^{[10] [11]}
• Vitamin D levels (25‑OH and sometimes 1,25‑OH): Identify supplement excess or other vitamin D–related causes. Correcting vitamin D intake can be part of management. ^[11]
• Urine calcium and imaging: Urine calcium can help characterize the disorder; imaging of bones or lungs may be done to look for cancer involvement or other causes. These steps are tailored to your clinical picture. ^{[1] [11]}

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When to Treat Urgently

• High calcium can be a medical emergency, especially with dehydration, confusion, very high values, or heart rhythm concerns. Hospital treatment with IV fluids is the most important first step to quickly lower calcium and protect the heart and brain. ^{[1] [12] [2]}
• Loop diuretics (like furosemide) may be added after adequate hydration if fluid overload is a risk or calcium remains high. These increase urinary calcium excretion. ^[12]
• Other measures may include calcitonin for short‑term lowering, and dialysis if there’s significant kidney impairment. These are reserved for more severe cases. ^[2]

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Ongoing and Cause‑Directed Management

• Primary hyperparathyroidism: If PTH is high with high calcium, you may benefit from parathyroid surgery, which can cure the hypercalcemia in appropriate candidates; others can be monitored or treated medically based on established criteria. Shared decision‑making is used to choose the best option for you. ^{[8] [13]}
• Cancer‑associated hypercalcemia: Beyond hydration, your team may use anti‑resorptive therapies such as bisphosphonates or denosumab to reduce bone calcium release, and importantly, optimize melanoma treatment to address the underlying driver. Treating the cancer often improves calcium control. ^[2]
• Supplement‑related hypercalcemia: Stopping excess vitamin D or calcium and ensuring adequate fluids generally resolves the issue; your team will guide safe re‑introduction if needed. Diet and medication review are part of care. ^{[14] [4]}

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What This Means for Prognosis

• Hypercalcemia is often reversible with proper treatment, especially when due to parathyroid overactivity or supplement excess. Many people recover quickly once the cause is addressed. ^{[1] [2]}
• If hypercalcemia is driven by cancer activity, it can reflect disease burden and may worsen with progression, making coordinated oncology care essential. Your team will focus both on immediate calcium control and melanoma treatment. ^[6]

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Practical Steps You Can Take Now

• Tell your care team about all supplements (calcium, vitamin D) and medications. Small changes can make a big difference. ^[4]
• Stay well hydrated unless you’ve been told to restrict fluids; dehydration can worsen calcium levels. Hydration is a cornerstone of acute management. ^[2]
• Watch for symptoms like fatigue, nausea, constipation, increased thirst/urination, confusion, or palpitations, and seek prompt care if they appear. These can signal more serious elevations. ^[4]
• Ask about your PTH, PTHrP, and vitamin D results, and how they guide your plan. Understanding the cause helps you and your team choose the right treatment. ^{[8] [10] [11]}

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Key Takeaway

High calcium in someone with melanoma is a signal to evaluate promptly, because there are multiple possible causes, many of which are treatable. Early testing and targeted treatment can lower risks and improve how you feel, while coordinated melanoma care addresses the root cause when cancer is involved. ^{[1] [2] [6]}