What Does Low Back Pain Mean in Cancer? Causes and Treatment Options

What Is Low Back Pain?

Low back pain is a common symptom with many possible causes, including muscle strain, nerve problems, and spinal disorders. It can also occur in cancer patients, ranging from a mild ache to severe pain that limits daily activities.

Causes of Low Back Pain in Cancer Patients

Low back pain in cancer patients can arise through several mechanisms:

1-Tumor Invasion or Metastasis

Bone Metastases

• Cancer cells travel through the bloodstream and settle in the bones of the spine.
• Breast, prostate, lung, and kidney cancers most commonly metastasize to the spine.

These metastases include:

• Osteolytic lesions (bone destruction): Common in lung, kidney, and thyroid cancer and multiple myeloma. The risk of pathological fracture increases.
• Osteoblastic lesions (bone formation): Particularly in prostate cancer. The spine becomes hardened but can also become fragile.

Clinical features:

• Pain that persists at rest and worsens at night
• Pain aggravated by mechanical loading
• Sudden acute pain due to a fracture

Spinal Cord or Nerve Root Compression

Spinal metastases can expand and compress the spinal canal or nerve roots.

This is an oncological emergency.

Symptoms:

• Severe localized pain
• Radicular pain (radiating into the legs, with burning or electric-shock sensations)
• Numbness, tingling, weakness
• Loss of bladder or bowel control; urgent intervention is needed!

2-Nerve Compression (Neuropathic Pain)

A tumor mass or metastasis can directly compress nerve tissue.

Characteristic features:

• Burning, stabbing, or electric-shock-like pain
• Allodynia (pain caused by a normally nonpainful stimulus)
• Numbness, loss of sensation
• Muscle weakness

Neuropathic pain in cancer patients is harder to treat than mechanical pain and usually requires opioids and adjuvant drugs such as gabapentin, pregabalin, or duloxetine.

3. Treatment-Related Causes

After Surgery

• Nerve damage or scar tissue (fibrosis) after spinal or pelvic surgery can cause chronic pain.
• This pain is generally chronic and neuropathic.

After Radiotherapy

• Radiotherapy to spinal bones can reduce bone density and increase osteoporotic fracture risk.
• Fibrosis in surrounding soft tissues can also cause musculoskeletal pain.

Chemotherapy / Targeted Drugs

• Platinum agents (cisplatin, oxaliplatin), taxanes (paclitaxel, docetaxel), and drugs such as bortezomib cause peripheral neuropathy.
• This may worsen low back pain alongside burning, tingling, and numbness in the legs.

4. Non-Cancer Causes (Coexisting Conditions)

• Cancer patients can also have the usual causes of low back pain seen in other people:
• Muscle strain: Prolonged inactivity, poor posture, excessive loading.
• Degenerative spinal disorders: Disc herniation, spondylosis, facet joint osteoarthritis.
• Osteoporosis: Related to cancer treatment (e.g., corticosteroids, aromatase inhibitors, hypogonadism) or aging. Osteoporosis, spinal fractures, and acute low back pain.

Who Develops Low Back Pain?

Anyone can develop low back pain, but it becomes more common with age. Poor posture, lack of exercise, and weak abdominal and lower back muscles can contribute to its development or persistence.

In cancer patients, low back pain may be caused or worsened by the primary tumor, metastatic spread, or treatment side effects such as radiotherapy or chemotherapy-induced neuropathy.

Cancer patients at higher risk of low back pain include:

• Those with bone metastases (most commonly in prostate, breast, and lung cancer).
• Those who develop spinal cord compression
• Those with tumors invading the spinal column

👉 Low back pain caused by a tumor compressing the spinal cord is a medical emergency.

Treating Low Back Pain in Cancer Patients

1. Treatment of the Underlying Cause

The mechanism causing the pain must be investigated:

Metastatic spinal involvement / metastatic spinal cord compression (MSCC)

• An emergency; high-dose corticosteroids, such as dexamethasone, should be started.
• Surgical decompression and stabilization should be considered in suitable patients.
• Radiotherapy (e.g., a single 8 Gy fraction) is standard for pain palliation and tumor control.

Bone metastases

• Radiotherapy: The most effective palliative approach for localized metastases.
• Radioisotope treatments (e.g., Ra-223, Sr-89): For widespread bone metastases.
• Surgery / vertebroplasty / kyphoplasty: For pathological fractures or instability.

Treatment-related causes (e.g., neuropathy, osteoporosis, postoperative pain)

• Managed with medication adjustments, bone-strengthening treatments, and physical therapy.

2. Pharmacological Pain Management (WHO Analgesic Ladder)

Step 1 (mild pain): Paracetamol, NSAIDs.

Step 2 (moderate pain): Weak opioids (tramadol, codeine) ± nonopioid.

Step 3 (severe pain): Strong opioids (morphine, oxycodone, fentanyl, hydromorphone).

Adjuvant drugs (particularly for neuropathic pain):

• Anticonvulsants: Gabapentin, pregabalin.
• Antidepressants: Duloxetine, amitriptyline.

Corticosteroids: Reduce tumor edema and nerve compression.

3. Drugs Supporting Bone Health

• In patients with bone metastases, bisphosphonates (zoledronic acid) or denosumab:
• Reduce skeletal-related events (fracture, need for RT, spinal cord compression).
• May relieve pain.
• Dental examinations are mandatory because of the risk of jaw osteonecrosis.

4. Nonpharmacological and Supportive Treatments

• Physical therapy and rehabilitation: Improve muscle strength, flexibility, and mobility.
• Braces / orthoses: Support spinal stability.
• Psychosocial support: Reduces pain perception and improves quality of life.
• Complementary methods (limited evidence): Acupuncture, relaxation exercises, meditation.

5. Managing Emergencies

• Low back pain with loss of bladder/bowel control or leg weakness raises suspicion of spinal cord compression, requiring urgent MRI and oncology/neurosurgical consultation.
• Delayed treatment can lead to permanent paralysis.

Low back pain in cancer patients should never be underestimated. The first step must be to consult an oncologist or the relevant specialist, followed by a combination of pain control, oncological treatment, and supportive approaches according to the diagnosis.

A cancer patient with low back pain, particularly with the following symptoms, should seek medical care urgently:

• Leg weakness, numbness, tingling
• Loss of bladder or bowel control
• Sudden, severely worsening pain
• Pain that wakes them at night or does not improve with rest