A 60-year-old man who survived nasopharyngeal cancer developed dangerously high calcium levels in his blood multiple times. Doctors initially thought his cancer had returned and was causing the problem, but tests showed something different was happening. Instead, two separate issues were working together: he was taking too many calcium supplements through a feeding tube, and radiation treatment had damaged his pituitary gland (a small gland in the brain that controls hormones). When doctors stopped the supplements and gave him hormone replacement therapy, his calcium levels returned to normal. This case teaches doctors to look beyond cancer as the cause of high calcium in cancer survivors.

The Quick Take

  • What they studied: Why a cancer survivor kept having dangerously high calcium levels in his blood, even after his cancer treatment
  • Who participated: One 60-year-old man who had nasopharyngeal cancer (cancer in the back of the nose), received radiation to his head, had kidney disease, and was taking calcium supplements through a feeding tube
  • Key finding: The high calcium wasn’t caused by cancer spreading, but by a combination of taking too many calcium supplements and radiation damage to the pituitary gland that controls hormone levels
  • What it means for you: If you’re a cancer survivor with high calcium levels, doctors should check for non-cancer causes like supplements and radiation damage to the pituitary gland, not just assume the cancer is back. This may help catch and treat the real problem faster.

The Research Details

This is a case report, which means doctors documented the medical story of one patient in detail. They described his symptoms, test results, and what treatments worked. The patient came to the hospital with very high calcium levels (11.0-14.9 mg/dL, when normal is around 8.5-10.2 mg/dL) that kept coming back. Doctors ran many blood tests, imaging scans, and hormone tests to figure out what was causing the problem.

The doctors looked at all the clues carefully: blood tests showed calcium and phosphate were high, but the hormones that usually control calcium (PTH and PTHrP) were actually low. This was unusual and suggested the problem wasn’t from the cancer or the parathyroid glands. They also discovered the patient had been taking calcium supplements through a feeding tube in his stomach for a long time.

Additionally, special hormone tests showed the patient’s pituitary gland (which sits at the base of the brain) wasn’t working properly. Brain imaging confirmed that radiation from his cancer treatment had likely damaged this gland. The doctors put all these pieces together to solve the puzzle.

Case reports are important because they teach doctors about unusual situations they might not see often. This case is valuable because it shows that cancer survivors can develop high calcium from causes other than cancer, and doctors need to think carefully about all possibilities. It also shows how radiation treatment can cause problems years later by damaging the pituitary gland.

This is a detailed medical case study of one patient, so it shows what happened in this specific situation but may not apply to everyone. The doctors did thorough testing and used multiple types of tests to confirm their findings, which makes the case more reliable. However, because it’s only one patient, we can’t say for certain that this will happen to other cancer survivors. This case is most useful for teaching doctors to consider these possibilities in similar patients.

What the Results Show

The main discovery was that the patient’s high calcium levels came from two separate problems working together. First, he was taking calcium supplements through a feeding tube in his stomach, and his kidneys weren’t working well enough to get rid of the extra calcium (this is called calcium-alkali syndrome). Second, his pituitary gland had been damaged by radiation from his cancer treatment years earlier, which meant his body wasn’t making enough cortisol (a hormone that helps control calcium and other body functions).

The blood tests showed an unusual pattern: calcium was very high, but the hormones that normally cause high calcium (PTH and PTHrP) were actually low. This pattern was the key clue that the problem wasn’t from cancer or parathyroid disease. The doctors also found that his kidneys were leaking too much calcium and phosphate into his urine, which was strange because his kidneys weren’t working well.

When doctors stopped giving him calcium supplements and started him on hormone replacement therapy (prednisolone and fludrocortisone), his calcium levels came back to normal within a reasonable time. His kidney function also improved. This confirmed that the supplements and the hormone deficiency were the real causes of his problem.

The patient also had kidney disease (stage 3 chronic kidney disease), which made the situation more complicated. His kidneys couldn’t filter out the extra calcium properly, which made the problem worse. The radiation damage to his pituitary gland was confirmed by brain imaging, which showed increased activity at the base of the skull where the pituitary sits. The patient also had low blood pressure, which improved when he started taking the hormone replacement therapy.

Most cases of high calcium in cancer patients are caused by the cancer itself producing hormones that raise calcium levels. This case is different because the calcium problem wasn’t from cancer at all. Doctors have known for a long time that radiation can damage the pituitary gland, but this case shows how that damage can lead to high calcium levels years after treatment. The combination of calcium supplements and pituitary damage is an unusual cause of high calcium that doctors might not think of right away.

This is a case report of just one patient, so we can’t know if this will happen to other cancer survivors. Every patient is different, and their situation might be different. The doctors didn’t do experiments to prove that radiation caused the pituitary damage—they used imaging and hormone tests to suggest it was likely. We also don’t know how common this problem is in other nasopharyngeal cancer survivors or in people who take calcium supplements and have kidney disease.

The Bottom Line

For cancer survivors with high calcium levels: doctors should test for non-cancer causes, especially if blood tests show low PTH and PTHrP levels. This includes checking for calcium supplement overload and pituitary gland damage from radiation. (Confidence: Based on one detailed case, this is a teaching point for doctors rather than a proven treatment for all patients.) For people taking calcium supplements: work with your doctor to make sure you’re taking the right amount, especially if you have kidney disease. For cancer survivors who received head or brain radiation: ask your doctor about checking your pituitary gland function, especially if you develop symptoms like low blood pressure, fatigue, or unusual calcium levels.

This case is most important for doctors treating cancer survivors, especially those who had radiation to the head or brain. It’s also relevant for patients who are nasopharyngeal cancer survivors or who take calcium supplements while having kidney disease. People with kidney disease should be aware that taking too many calcium supplements can be dangerous. This case is less directly relevant to people without cancer history or kidney disease, though the lesson about checking for multiple causes of medical problems applies broadly.

In this patient, stopping the calcium supplements and starting hormone therapy led to improvement in calcium levels over weeks to months. However, the timeline for improvement may be different for different people depending on how long they’ve had the problem and how severe it is. Pituitary gland damage from radiation can take years to develop, so cancer survivors should have ongoing monitoring.

Want to Apply This Research?

  • If you’re a cancer survivor or take calcium supplements, track your calcium intake daily (from food and supplements), any symptoms like weakness or confusion, and blood pressure readings. Log any new symptoms and share with your doctor at appointments.
  • Work with your doctor to review all calcium and vitamin D supplements you’re taking. If you have kidney disease, ask your doctor what the right amount of calcium is for you. Set reminders to take only the amount your doctor recommends, and avoid adding extra calcium supplements without checking first.
  • Cancer survivors should have regular blood tests to check calcium, kidney function, and pituitary hormones (especially if they had head or brain radiation). Track any symptoms like fatigue, low blood pressure, or unusual thirst. Report these to your doctor promptly, as they could signal pituitary problems or calcium imbalance.

This case report describes one patient’s experience and should not be used to diagnose or treat yourself or others. High calcium levels can be serious and require medical evaluation. If you are a cancer survivor experiencing symptoms like weakness, confusion, nausea, or unusual thirst, contact your doctor immediately. If you take calcium supplements, especially while having kidney disease, discuss the appropriate dose with your healthcare provider. This information is educational and not a substitute for professional medical advice, diagnosis, or treatment.