Several types of cancer can cause back pain, but the most common culprits are breast, lung, and prostate cancers that have spread to the spine. That said, cancer is a rare cause of back pain overall. Fewer than 1% of people who visit a doctor for low back pain turn out to have an underlying malignancy. Understanding which cancers cause back pain, and what that pain feels like compared to ordinary back problems, can help you decide whether your symptoms deserve closer attention.
Cancers That Spread to the Spine
The most frequent reason cancer causes back pain is metastasis, meaning cancer cells from another part of the body have traveled to the spinal bones. Metastatic tumors account for roughly 97% of all spinal tumors. The primary cancers that spread to the spine most often, in descending order, are breast (21%), lung (19%), prostate (7.5%), kidney (5%), gastrointestinal cancers (4.5%), and thyroid (2.5%). In autopsy studies of patients with known breast or prostate cancer, spinal metastases were found in 70% to 90% of cases, though many of those people never experienced symptoms during their lifetime.
The thoracic spine (mid-back) and the junction between the mid-back and lower back are the most common landing spots, accounting for about 70% of spinal metastases. The lower back and sacrum make up another 20%, while the cervical spine (neck) is less frequently affected. Pain from spinal metastases tends to be persistent, gradually worsening over weeks, and often worse at night or when lying down. It doesn’t follow the usual pattern of mechanical back pain, which improves with rest and worsens with movement.
Cancers That Cause Back Pain Directly
Some cancers don’t need to metastasize to the spine to cause back pain. They produce pain by pressing on nearby nerves or structures, or by referring pain to the back through shared nerve pathways.
Pancreatic Cancer
Pancreatic cancer is well known for causing a dull ache in the upper or middle back, particularly when the tumor grows in the body or tail of the pancreas. In that location, the tumor can press directly against the spine. Patients often describe pain that starts in the middle of the abdomen and radiates through to the back. This pain tends to come and go at first, then becomes more constant as the tumor grows.
Kidney Cancer
Kidney tumors can cause flank or lower back pain on one side, though most kidney cancers today are found incidentally on imaging before they produce any symptoms at all. The classic combination of flank pain, blood in the urine, and a palpable abdominal mass is actually uncommon. When back pain does occur, it typically signals a larger tumor. The average kidney tumor at diagnosis is about 5.4 centimeters, but tumors that cause noticeable back pain are often considerably bigger.
Pancoast Tumors (Lung Cancer)
A Pancoast tumor is a lung cancer that grows at the very top of the lung and behaves quite differently from typical lung cancer. Instead of coughing or chest pain, it almost always causes severe shoulder pain, often radiating down the arm toward the pinky-finger side of the wrist. It can also cause pain in the upper back, neck, and upper ribs by pressing on the nerve bundle that runs from the upper chest into the neck and arms. Many people initially mistake this for a pinched nerve. If that type of lingering shoulder or upper back pain doesn’t resolve within a couple of weeks, it warrants evaluation.
Multiple Myeloma and Bone Destruction
Multiple myeloma is a blood cancer that grows inside the bone marrow and deserves its own mention because back pain is one of its hallmark symptoms. Myeloma cells disrupt the normal cycle of bone rebuilding by infiltrating the microscopic compartments where old bone is broken down and new bone is formed. This leads to tiny holes in the bone called lytic lesions, which appear as “punched-out” spots on imaging. When these lesions weaken vertebrae enough, compression fractures can occur, sometimes from something as minor as bending over or lifting a grocery bag. The resulting pain is often sudden, sharp, and localized to a specific area of the spine.
Primary Tumors That Start in the Spine
Rarely, cancer originates in the spine itself rather than traveling there from somewhere else. Osteosarcoma of the spine accounts for only about 2% of all osteosarcomas and is most common in teenagers and young adults, with a smaller second peak in people over 50 who have pre-existing bone conditions like Paget’s disease. Chordoma is another rare primary spine tumor that develops from leftover embryonic cells. About 60% of chordomas arise in the sacrum (the triangular bone at the base of the spine), where they tend to grow slowly and cause symptoms like constipation, tailbone pain, or urinary problems before back pain becomes prominent. These tumors behave very differently from metastatic disease and require specialized treatment.
How Cancer-Related Back Pain Feels Different
Most back pain is mechanical, caused by muscle strain, disc problems, or arthritis. Cancer-related back pain tends to have a distinct pattern: it starts gradually, gets steadily worse over weeks to months, and doesn’t respond to the usual remedies like rest, stretching, or over-the-counter painkillers. Night pain that wakes you from sleep is often cited as a warning sign, though on its own it isn’t a reliable indicator of cancer.
Clinicians look for a combination of features rather than any single red flag. A previous history of cancer is by far the strongest individual predictor. A Cochrane review found that most commonly cited red flags, including age over 50, pain lasting more than a month, and unexplained weight loss, have high false-positive rates when used alone. Of the red flags recommended in major clinical guidelines, only a previous history of cancer raised the probability of malignancy above 2% on its own. The takeaway is that no single symptom reliably points to cancer, but a cluster of concerning features together warrants further investigation.
Accompanying symptoms that raise concern include unexplained weight loss, persistent fatigue, new weakness in the legs, numbness spreading from the trunk downward, and any change in bladder or bowel control.
When Back Pain Becomes a Neurological Emergency
Metastatic spinal cord compression occurs when a tumor presses on the spinal cord itself. Back pain is present in about 95% of these cases, but the critical warning signs are neurological: leg weakness, difficulty walking, loss of sensation, and problems with bladder or bowel function. This is a genuine emergency. Guidelines call for an urgent full-spine MRI within 24 hours and definitive treatment shortly after. Patients who lose the ability to move their legs and go untreated for more than 48 hours are unlikely to recover useful function. Pain that increases with straining (coughing, sneezing, bearing down) and worsening nighttime spinal pain are additional warning signs of cord compression.
How Cancer-Related Back Pain Is Investigated
MRI is the gold-standard imaging tool when cancer is suspected as a cause of back pain. According to the American College of Radiology, MRI is superior to CT or X-ray for localizing spinal tumors, assessing how far they extend, and distinguishing cancerous bone marrow changes from benign ones. An MRI without contrast can often be sufficient for evaluating bone marrow abnormalities, using specific sequences that differentiate between harmless changes and malignant ones. When there’s concern about disease within or around the spinal canal itself, contrast-enhanced MRI provides additional detail.
Standard X-rays can sometimes reveal signs of metastatic disease. One classic finding is the “winking owl sign,” where destruction of part of a vertebra makes it look like the vertebra is winking on a head-on X-ray. But X-rays can miss early disease, which is why MRI remains the preferred study when clinical suspicion is high enough to warrant imaging.