Are Weakness or Numbness a Sign of Prostate Cancer?
Feeling weakness or numbness in your lower extremities (or your upper extremities) is not a symptom to ignore. While there are many reasons why this experience can occur, it may be related to prostate cancer. Numbness or weakness in the lower extremities can be a result of advanced prostate cancer that has spread to the bones, specifically the spinal cord. When this happens, the cancer is said to have metastasized. When cancerous cells reach bones, they can destroy them, leading to pain, instability, and even fractures. When this happens at certain points on the spinal cord, nerves can get compressed or damaged, leading to neurological symptoms including weakness, numbness, or even paralysis. This is called metastatic spinal cord compression, or MSCC.
Ruling out a tumor flare
This experience may also occur as a result of tumor flare phenomenon, a side effect of treatment with hormonal therapies that temporarily increase tumor growth before slowing it down. These tumors can grow rapidly after starting treatment and begin to press on the spinal cord and nerves inside. Fortunately, tumor flare phenomenon has been well-studied, and hormonal treatments are often co-administered with medications designed to prevent the flare from happening. For this reason, tumor flare is less common, and the main reason for extremity weakness or numbness is from cancer that has metastasized. Cancer that has spread to the spinal cord is treated in the same manner as cancer that has spread to other bones.
Treatment, in this case, is often palliative. Palliative care involves treating symptoms, such as weakness or numbness, but not curing the underlying condition causing the symptom. Although the treatment regimen for an individual’s prostate cancer can be adjusted in an attempt to cure the cancer, it typically is not curable once it has become widespread in the bones. The main types of treatment for cancer that has spread to the bones as a result of prostate cancer include medications, radiation, and surgery.1,2
Breaking down medications
When cancer spreads to the bones, it typically begins eating away at them. Some medications including bisphosphonates like Zometa or monoclonal antibodies like Xgeva target the healthy bone growth regulation process in our body to favor bone building and slow down bone destruction.
Corticosteroid medications, also known as steroids, are a class of drugs designed to mimic naturally-occurring corticosteroids produced by the adrenal cortex above the kidneys. Corticosteroids carry out a wide range of functions in the body and can be harnessed to prevent or decrease inflammation or reduce pain related to bone metastases. A common corticosteroid used to treat spinal cord compression is called dexamethasone.
Radiopharmaceuticals belong to a class of medications that are considered systemic radiation therapies. The most common radiopharmaceuticals used in the treatment of advanced prostate cancer are Strontium-89 (Metastron), Samarium-153 (Quadramet), and Radium-223 (Xofigo). The radioactive elements in radiopharmaceuticals are attracted to areas in the body that are experiencing rapid bone turnover, such as where the cancer has metastasized to the bones and is destroying them. These agents release radiation directly to the bone lesions, also relieving pain.1,3-5
Radiation therapy, including external radiation therapy, also called external beam therapy (EBT), involves focusing a beam of high-energy radiation (or X-rays) onto a specific spot on the body from the outside. The target of this type of therapy is the exact location of an active cancerous tumor. The location of the tumor is determined by imaging procedures.
Radiation therapy may be used with the intent to cure an individual’s cancer, however, external beam radiation to treat cancer that has metastasized to the bones is typically for pain or symptom relief only. Targeting a malignant tumor on a bone, including on the spine, before it does too much damage, can lead to pain relief, as well as the prevention of future fractures and instability. Radiation therapy on the spine may be able to shrink tumors, thus relieving pressure on the spinal cord and nerves.6,7
Surgery is typically the least common method of treating metastatic spinal cord compression since it is the most invasive and carries the greatest amount of risk and recovery time. However, in some instances, bone destruction can lead to great instability that can eventually lead to painful fractures. These fractures can often be very painful, which is why in some cases it may be advantageous to increase skeletal stability via surgery. In these cases, cement, metal pins, or metal plates can be inserted into the bones to make them stronger. Your surgeon may also attempt to directly remove portions of tumors compressing the spinal cord, for immediate symptom relief. Surgery may be followed by radiation therapy, but also can involve a long hospital stay or recovery time, especially if it’s a surgical procedure involving the spine.1
If symptoms do not cease, or if any of the above options are not indicated for your situation, you should discuss with your healthcare team, and you may also be able to seek support from an occupational therapist or wear a full-time back brace to keep your spine stabilized.