Patients undergoing cancer treatment can develop side effects from the therapy or other illnesses due to the therapy or the cancer itself. These can be related to hormones or endocrine conditions, also termed oncologic endocrinopathies (with “onco” meaning tumor and relating to cancer).

Endocrinopathies in cancer represent a complex interplay between two or more disorders, reflecting how malignancies can disrupt normal hormone function. Oncoendocrinology is an evolving medical field that includes screening, diagnosing and managing endocrine diseases in patients with either active cancer or cancer survivors undergoing surveillance.

As the diagnosis and management of endocrine disease in the cancer patient can be challenging, oncoendocrinology centers are a relatively novel concept designed to bridge the gap between these two disciplines to specifically address both the endocrine and oncologic needs of this complex population.

Oncologic endocrinopathies arise when tumors, either primary or metastatic, affect endocrine glands, leading to abnormal hormone secretion. This can occur through direct invasion of endocrine tissues, hormone production by tumors or paraneoplastic syndromes — where tumors cause hormone imbalances indirectly.

There are several types of oncologic endocrinopathies.

1. Hypercalcemia of malignancy: This is one of the most common endocrinopathies associated with cancer. It usually results from metastases to the bone or paraneoplastic syndromes. Tumors, particularly lung cancer, breast cancer and multiple myeloma, can produce a hormone that leads to increased calcium release from bones, causing elevated calcium levels in the blood. Common signs and symptoms of hypercalcemia are body aches and pains, constipation, memory issues and kidney stones.

2. Adrenal issues: The adrenals are two small triangular glands found above the kidneys that produce several hormones, such as cortisol, aldosterone and catecholamines. Some tumors can cause an excess of these hormones, and patients can present with high blood pressure and elevated blood glucose levels.

Another condition that can occur is a lack of cortisol, known as adrenal insufficiency (AI) where patients experience weakness, fatigue, low blood pressure and low glucose levels. AI can occur after some cancer therapies or after prolonged use of steroids. If you have been taking high doses of steroids for more than two to three weeks, you should not stop the steroids abruptly but slowly taper to lower doses every few days.

3. Thyroid dysfunction: Certain cancer therapies can affect the thyroid gland, reducing the ability of the thyroid to make thyroid hormone, leading to hypothyroidism. In this condition patients can feel tired and sluggish, have cold intolerance and constipation, and weight gain.

4. Elevated glucose levels (hyperglycemia): Steroids are a well-known cause of hyperglycemia. Some newer agents to treat cancer can also elevate glucose levels. If you are a patient with diabetes who receives steroids during treatment, talk to your doctor about adjusting your medications and the possible intermittent use of insulin to control your glucose levels.

5. Osteoporosis: Several cancer therapies are associated with osteoporosis. Post-menopausal women and elderly patients should be assessed with a bone mineral density at baseline prior to therapy and at regular intervals thereafter.

6. Carcinoid Syndrome: This is associated with neuroendocrine tumors, particularly in the gastrointestinal tract. Carcinoid syndrome results from excessive secretion of serotonin and other vasoactive substances leading to symptoms of facial flushing, diarrhea and wheezing, particularly after eating.