Targeted Radiation Therapy: A Technological Leap for the Treatment of Prostate Cancer

Prostate cancer is the second most common form of cancer in men after lung cancer. Patients often initially seek medical attention for urinary problems. Diagnosis is mainly done with blood samples to determine the presence of PSA, a type of protein. If the PSA value exceeds a certain threshold, physicians will confirm the presence of cancer through other means.

For early-stage prostate cancer patients, the most common treatment is the removal of the prostate gland. Because prostate cancer relies on the male hormone (androgen) to grow, doctors may recommend complete removal of the testicles (androgen producing organ) to reduce the androgen level in the body. Patients undergo hormone therapy, chemotherapy, radiation therapy, and / or brachytherapy as well.

While hormone therapy is still the most common form of treatment for prostate cancer, it is almost completely ineffective in cases of "castrate-resistant prostate cancer" (CRPC) which continues to spread even in the absence or near-absence of androgen. The chances of survival for patients with this form of cancer are usually very low. However, ongoing research has yielded a new method of targeted therapy – itself an adaptation of the radiation therapy that has long been in use – with exciting results.

The radioactive substance used in this study is called lutetium-177 (177Lu) -PSMA-617 (Endocyte), a tiny radiolabeled molecule that selective binds to a type of protein present in prostate cancer cells. After the binding occurs, the radiation from Lu-177 destroys the prostate cancer cell, thereby directly reducing the size and arresting the metastasis of the cancer. This form of treatment also results in significantly less damage to other cells. The leader of this research effort, Dr. Hoffman from the Peter MacCallum Cancer Center in Australia, went as far as to say that “In this trial, we treated men who would have otherwise been directed to palliative care.

Apart from the targeted radiation therapy that is currently in development, we also have another type of targeted therapy in the form of enzalutamide and apalutamide, both of which are medications that have recently been approved as targeted therapy for prostate cancer patients with efficacy against the more hormone-sensitive prostratecancer (HSPC) as well as the castrate-resistant prostate cancer (CRPC). These targeted drug molecules bind to the androgen receptors on the surface of the prostate cancer cells, preventing them from being stimulated by with androgen. Starved of contact with the hormone, the cancer cells eventually die off. Studies have shown that using these two medications can stave off the need for chemotherapy, and significantly prolong the life of patients.

These latest developments show that advanced metastatic prostate cancer is no longer the end of the road for many patients. Medical advances continue to bring new hope to the horizon.

 

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