Former US President Joe Biden's illness has renewed public discussion about what happens when prostate cancer spreads to the skeleton.
Biden's prostate cancer has metastasised to his bones, which is described as painful and debilitating.
The discussion comes as experts raise concerns that many Kenyan men are diagnosed with prostate cancer at an advanced stage, when the disease may already have metastasised.
Dr Catherine Nyongesa, a consultant clinical and radiation oncologist and Director of Medical Services at Kenyatta National Hospital, explains that bone is the most common site of metastasis for advanced prostate cancer.
Studies suggest that bone involvement may occur in up to nine in 10 men with metastatic prostate cancer.
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The spine, pelvis, ribs, skull, and upper thigh bones are among the areas most frequently affected.
“Cancer cells can travel through the bloodstream and through the veins around the spine, which is why the backbone is often involved,” says Dr Nyongesa.
Bone metastases can cause persistent pain and weaken the bones, increasing the risk of fractures.
Extensive disease may also affect the bone marrow and contribute to anaemia, she explains.
“A person with prostate cancer who develops severe new back pain, leg weakness or numbness, or difficulty controlling urine or stool should seek emergency medical care,” advises the specialist. “These symptoms may indicate spinal cord compression.”
According to the specialist, prostate cancer that has spread to the bones is usually not curable, but it remains treatable. With appropriate treatment, many men can live for years.
In an interview with The Standard, Dr Nyongesa notes that hormone treatment is the foundation of care because prostate cancer commonly depends on male hormones to grow.
Hormone therapy may be combined with additional medicines such as abiraterone or enzalutamide, or with chemotherapy, depending on the patient’s health and the extent of the cancer.
Selected patients may also receive medications to strengthen the bones, while radiotherapy is highly effective at relieving pain from bone metastases and can be delivered in a single session or over several sessions.
Treatment, however, should be planned by a multidisciplinary team, she notes.
Dr Nyongesa says advances in cancer treatment have also opened the door to theranostics, an approach that combines imaging to identify a specific cancer target with targeted treatment directed against that same target.
In prostate cancer, doctors can target a protein called prostate-specific membrane antigen (PSMA), which is present in high amounts on many prostate cancer cells.
A PSMA PET-CT scan helps identify where PSMA-positive prostate cancer is located and whether the cancer is likely to respond to PSMA-targeted treatment.
If the scan confirms that the cancer has the appropriate target, lutetium-177 PSMA therapy can deliver radiation directly to cancer cells while limiting exposure to much of the surrounding healthy tissue.
The treatment is administered by injection in cycles.
The treatment can, however, have side effects, including fatigue, dry mouth, and reduced blood cell counts.
“This treatment is not suitable for every patient. Eligibility depends on the PSMA scan, prior treatment, blood counts, kidney function, and the patient's overall condition,” adds Dr Nyongesa.
PSMA PET-CT scanning and lutetium-177 PSMA therapy are available at selected specialist centres in Kenya.
Before starting treatment, patients should be assessed by their oncology team.
Eligibility, availability and cost should be confirmed directly with the treating centre, the oncologist advises.
However, the biggest challenge remains late diagnosis, with many men seeking care only after symptoms appear and the disease has already spread.
“Men should discuss prostate screening and PSA testing with a qualified clinician starting at about age 50, or earlier if they have a father or brother with prostate cancer or other significant risk factors. Early diagnosis offers more treatment options,” advises Nyongesa.