Pathologic Fractures From Cancer

This page is for people with cancer that has spread to bone, and the people caring for them. It covers the warning signs of a break, how the risk is judged, and how treatment works.

A pathologic fracture is a break through bone that was already weakened by disease. In cancer care, the weakness usually comes from a tumor deposit that has eaten into the bone from the inside. The bone gives way under a load it used to carry without trouble.

That is the part people find hard to believe. A healthy thigh bone needs a car crash to snap. A thigh bone hollowed out by cancer can break while you turn over in bed, step off a curb, or lift a kettle. The force was normal. The bone was not.

Call emergency services or go to the emergency department if any of these happen.

A bone may have broken if:

• Sudden severe pain starts in a limb, hip, or the back, with little or no injury behind it.
• You cannot stand on a leg, or you cannot lift an arm you could lift yesterday.
• A limb looks bent, twisted, or shorter than the other side.
• You heard or felt a crack, snap, or pop.
• Pain that had been building suddenly changes character and becomes far worse.

The spinal cord may be under pressure if:

• New or changed back or neck pain that is constant and aching, worse at night, or worse when you cough, sneeze or strain.
• Your legs feel weak, heavy, or clumsy, or you are tripping and catching your feet.
• You have numbness or pins and needles in both legs, or numbness in the saddle area. That means the inner thighs, buttocks and groin.
• Bladder or bowel control has changed in any way. Trouble starting, dribbling, leaking, or not feeling the urge.

Say plainly: "I have cancer and I think this may be spinal cord compression." The American Cancer Society calls this an oncology emergency: if it isn't treated right away, the person can become paralyzed.

Blood calcium may be dangerously high if you have:

• New confusion, drowsiness, or behavior that is not like you.
• Strong thirst and passing large amounts of urine.
• New constipation, nausea, or vomiting.
• Weakness and heavy tiredness that came on over a few days.

Also seek urgent care for a temperature of 38.0 °C / 100.4 °F or higher. The CDC uses 100.4 °F and the NCI uses 100.5 °F. Use the lower number.

Five cancers account for most spread to bone: lung, breast, thyroid, kidney and prostate. The spine, the top of the thigh bone and the pelvis are the sites most often affected. The upper arm bone is another common one.

Deposits that dissolve bone leave a hole where solid bone used to be. Once enough of the hard outer shell is gone, the bone cannot handle twisting or weight. Radiotherapy, steroids and some cancer drugs can thin bone further, and so can long spells of inactivity.

Many pathologic fractures announce themselves. Doctors call it prodromal pain: an ache in one exact spot that grows over days or weeks, hurts more when you put weight through it, and often nags at night. Some people have no warning at all and the fracture is the first sign.

If you have a spot like that, do not test it. Do not push through it to see how bad it is. Get it imaged first. A bone that is about to break can be fixed on a planned operating list, in daylight, with the cancer team involved. A bone that has already broken is fixed as an emergency, with a longer stay and a harder recovery.

Surgeons look at scans to judge how likely a weakened bone is to break, and may fix it before it breaks. Ask how the risk to your bone has been judged and what it means for you.

Surgery can strengthen or repair the bone. In the arm or leg, that often means a metal rod placed inside the bone. In the spine, bone cement or metal supports may be used to steady it.

Radiotherapy can ease pain from a bone deposit, and sometimes a single treatment is enough. The pain can get worse for a short time after radiation, called a pain flare. In a trial, a short course of the steroid dexamethasone reduced pain flares. Ask whether that is planned for you.

Bone-modifying drugs, such as zoledronic acid or denosumab, are usually added to lower the chance of the next fracture.

• Get weight-bearing instructions in writing. "Take it easy" is not an instruction. Ask: full weight, partial weight, or none at all?
• Use the walking aid you were given every time, including at 3am on the way to the toilet.
• Clear rugs, cables and clutter. Put a light within reach of the bed.
• Avoid twisting movements: getting out of a car, reaching behind you, opening a stiff window.
• Do not lift, carry or push anything heavy with an affected arm.
• Ask about a raised toilet seat, a shower stool, and grab rails before you need them.
• Keep taking pain medicine on schedule. Pain that is controlled means fewer sudden, jerky movements.

• American Cancer Society — Bone Metastases
• NCI — Cancer Pain (PDQ), Health Professional Version
• MedlinePlus — Hypercalcemia
• StatPearls (NCBI Bookshelf) — Pathologic Fractures
• StatPearls (NCBI Bookshelf) — Palliative Radiation Therapy for Bone Metastases
• StatPearls (NCBI Bookshelf) — Spinal Cord Compression
• NICE (NCBI Bookshelf) — Spinal Metastases and Metastatic Spinal Cord Compression (NG234)
• NICE (NCBI Bookshelf) — Metastatic Spinal Cord Compression (CG75)
• StatPearls (NCBI Bookshelf) — Malignancy-Related Hypercalcemia
• StatPearls (NCBI Bookshelf) — Bone Metastasis
• CDC — Watch Out for Fever (Preventing Infections in Cancer Patients)