This article discusses proton therapy for prostate cancer patients trying to decide between traditional radiation and proton-based therapy. It discusses treatment length, economics and the basics of prostate cancer.
Prostate cancer is the most common cancer suffered by males. The disease often strikes its patients over the age of 70, and a second and much smaller wave occurs after the age of 40. Some patients develop it in their late age and it goes undetected until death. Common symptoms include pain in the urogenital region, difficulty urinating and erectile dysfunction. The prostate specific antigen is a blood tests used to diagnose prostate cancer, and a digital rectal exam can find an enlarged prostate. If either of these abnormalities are suspected to be prostate cancer, a biopsy is then performed.
Females do not possess an exact duplicate of the prostate gland, so their rate of occurrence is zero. Prostate cancer has a variety of treatments like radiation and chemotherapy; surgical excision and more advanced pellet implantation. The treatment was developed in the mid-1950s in a research capacity, but widely-available private hospital centers came to the forefront in the early 1990s. Due to proton therapy data being available for over a half a century, most insurance companies cover outpatient treatment.
Basics and Mechanism of Action
A proton is a positively charged subatomic particle used in proton therapy. This therapy requires a cyclotron or synchrotron. These devices accelerate particles in a precise location. Proton therapy is equivalent to radiation therapy in terms of common terminology. Simply, proton therapy takes radiation and condenses it to a beam. This beam destroys cancer cells by physically breaking the structure so they are unable to replicate.
In order for precise treatment, a magnetic resonance imaging (MRI) and computed tomography (CT) is required to locate and guide the beam as a map in multiple axes. Patients enter a room and must stay still inside a device called a gantry. The two beams used are only a few millimeters wide, allowing for a concise treatment in the span of fifteen minutes.The treatment length is five times per week for eight weeks. Proton therapy uses more localized radiation than traditional. It is not an invasive procedure technically, and is designed to minimize damage to the tissue surrounding the prostate. The proton therapy itself is non-invasive, but a balloon is placed in the rectum to render the prostate immobile.
Proton therapy for prostate cancer treatment is not a first line treatment and can be considerably expensive, with rates averaging over $63,000. In a study conducted by Konski et al in the Journal of Clinical Oncology, proton-based radiation for prostate cancer is not cost-effective compared to x-ray radiation. This does not mean the treatment is without merit, and quality of life is a controversial empirical calculation. In the most recent and comprehensive trial from the University of Florida in 2009, the treatment benefits patients who had a lower risk of prostate cancer to begin with. After proton therapy, low risk patients (usually younger) are less likely to have a biochemical recurrence of their tumor within 10 years (6 percent versus 29 percent for traditional radiation). The treatment does not increase survival rate significantly compared to traditional radiation therapy.
American Society for Radiation Oncology (ASTRO) 51st Annual Meeting: Abstract 22. Presented November 2, 2009.
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