Many types of cancer increase the risk of weak, fragile bones that are prone to fracture (breaking). Kidney cancer is no exception. There are several ways kidney cancer and its treatment can affect bone health. Understanding your risk is the first step to protecting against injury.

Unfortunately, some people don’t realize they have weak bones until they break one. When bones get too weak, it’s known as osteoporosis.

If you’ve had kidney cancer, it’s important to look out for the early signs of osteoporosis before a fracture happens.

Here’s what you need to know about the risk of bone fractures with kidney cancer and its treatment. Your healthcare team can help you understand more about your individual risk and how to protect your bone health.

How Does Kidney Cancer Weaken the Bones?

Kidney cancer (also known as renal cancer) can affect your bones in various ways. Here are some potential impacts to keep in mind.

Bone Metastasis

One of the most common places for kidney cancer to metastasize (spread) to is the bones. Bone pain in the arms or legs can be a sign of bone metastasis. About a quarter of people with advanced renal cell carcinoma (RCC) — the most common type of kidney cancer in adults — develop bone metastasis.

If you notice bone pain, discuss it with your healthcare provider right away. Even if it’s been several years since your kidney cancer diagnosis, there’s still a risk that cancer cells remain after treatment and spread to the bone. That’s why bone pain is an important symptom to bring to your doctor as soon as you experience it.

Malnutrition

Poor nutrition raises the risk of bone problems and fractures. One study from Germany of people living with RCC found that around 49 percent reported unintentional weight loss. Diarrhea, poor appetite, and nausea are common problems that can contribute to weight loss.

However, fewer than 14 percent of those surveyed were offered help with nutrition, and 67 percent said they felt like healthcare providers don’t take their nutritional concerns seriously.

If you’re concerned about nutrition and weight loss, talk to your oncology team. Ask for a referral to a registered dietitian to help ensure an adequate diet for strong bones.

Hypercalcemia

Normally, the amount of calcium in the blood is tightly controlled by the kidneys. Hypercalcemia is a condition in which blood calcium levels are too high, typically due to bone destruction. Hypercalcemia is linked to kidney problems and bone fractures.

Your healthcare team can use blood tests to monitor for signs of hypercalcemia during and after kidney cancer treatment.

Diabetes and Other Health Conditions

Many people with kidney cancer deal with more than one health condition. When you have two or more coexisting conditions at the same time, they’re known as comorbidities. As treatment for kidney cancer improves, people are living longer with the disease. Age is a shared risk factor for many comorbidities.

Some of the common comorbidities with kidney cancer raise the risk of fractures, especially diabetes. Studies suggest that about a quarter of people with kidney cancer have diabetes.

Overlapping risk factors for these diseases include:

• Obesity
• Chronic inflammation
• Low vitamin D levels
• Inactive lifestyles

Studies suggest that people with diabetes are more likely to have fractures, even when their bone density looks normal on bone scans. The term “diabetic bone disease” is used to describe bone quality issues that don’t always look like osteoporosis.

In addition, some (but not all) diabetes medications can negatively affect bone health.

Effects of Kidney Cancer Treatment

Certain medications used for treating advanced kidney cancer may have bone-related side effects.

Targeted Therapies

Tyrosine kinase inhibitors (TKIs) are a type of targeted therapy used in kidney cancer. Examples include sunitinib and sorafenib. These medications inhibit some molecular factors involved in bone remodeling, leading to problems in bone metabolism.

TKIs can also cause secondary hyperparathyroidism (increase of parathyroid hormone) by reducing blood levels of calcium and phosphorus (bone minerals), increasing fracture risk over time.

Immunotherapies

Immunotherapies known as immune checkpoint inhibitors (ICIs) can also cause low calcium levels. The medications, including nivolumab and ipilimumab, are sometimes combined with TKIs. Although it’s not clear what the true risk of bone fractures may be, a known complication is bone loss in the jawbone.

That being said, all cancer treatment is a balancing act between potential risks and potential benefits. Your healthcare team can help you weigh the benefits and risks of different treatment options and their potential side effects.

Other Factors Affecting Bone Health

Bones can also get weaker for reasons that aren’t related to kidney cancer. In general, bone mass decreases with age. Other risk factors include:

• Underweight or malnourishment
• Family history of osteoporosis
• Menopause
• History of heavy drinking
• Hyperthyroidism (high thyroid hormone levels)
• Low estrogen or testosterone levels
• Sedentary lifestyle
• Smoking

In addition, other health conditions and medications may cause weaker bones. Your healthcare provider can look at the bigger picture to determine your overall risk and come up with a plan to monitor and treat weak bones.

How To Reduce Your Risk of Fractures

Your kidney cancer specialist can help you understand your personal risk for bone issues. They can help you decide if bone density screening or other tests might be a good idea based on your symptoms and medical history.

A bone density scan, such as a dual-energy X-ray absorptiometry (DEXA) scan, can check the minerals in your bones for signs of weakness.

Understanding your risks can help you make thoughtful lifestyle choices and treatment decisions.

Know the Signs of Weakening Bones

Potential signs of weak bones include:

• Losing height or developing a curved back
• Having broken bones from a minor injury
• Experiencing back pain or stiffness in your joints

Take Steps To Keep Bones Healthy

You can support strong bones by:

• Doing weight-bearing exercises that strengthen your muscles
• Eating enough protein
• Getting the right amount of calcium and vitamin D

If you have osteoporosis, you may need to be careful about the type of exercise you do. In some cases, medications like bisphosphonates and denosumab can be helpful for weak bones. But these treatments also come with side effects. Again, your doctor can help you weigh risks versus benefits.

You can also take steps to prevent injuries. Simple changes, like buying shoes that fit well and clearing your living space of tripping hazards, can make all the difference. If you have any symptoms like dizziness, balance problems, or poor vision that could increase your chances of a fall, address them with your healthcare team.

Join the Conversation

On MyKidneyCancerTeam, people share their experiences with kidney cancer, get advice, and find support from others who understand.

Have you experienced a fracture or other signs of weak bones since being diagnosed with kidney cancer? Let others know in the comments below.