What is stereotactic radiotherapy in the treatment of prostate cancer? How does it compare to other treatments?

Prostate cancer occurs in Australia most frequently diagnosed cancer. One in six men will be diagnosed before the age of 85.

Cancers are abnormal groups of cells that grow uncontrollably and begin to invade nearby areas. They can also spread to other organs in the body. This is called metastasis.

Treatment of early-stage disease, when the cancer is confined to the original site, focuses on that single area, most often with surgery or radiation therapy. Treating advanced disease once it has spread often relies on whole-body treatments such as chemotherapy or immunotherapy.

A more advanced form of radiation therapy, called stereotactic ablative radiation therapy, can be effective in treating both early and advanced cancers. How does it work? And how does this relate to existing therapies?

Delivers a higher dose to a smaller target

Stereotactic radiotherapy uses high doses of radiation to target and kill cancer cells. It uses newer machines that can deliver very focused beams of radiation. Combined with advances in imaging and radiotherapy planning software, this allows clinicians to “track” and target tumors.

This ensures such high precision – with targeting accuracy of less than 1 mm – that cancers can be safely treated with minimal risk of damage to surrounding robust organs.

Having a higher dose means that radiation therapy can be delivered in fewer treatments (one to five sessions over one to two weeks), whereas previously it was divided into many petite doses (20 to 40) given over weeks or even months.

Stereotactic radiotherapy is increasingly used in cancer treatment brain AND lungs. However, recent data has shown that it can also effectively treat prostate cancer.

What did the recent study show?

AND test published this month in the Novel England Journal of Medicine compared two groups of patients with early prostate cancer whose median age was 69.8 years. Half (433 participants) received five sessions of stereotactic radiotherapy, the other half (431 participants) received standard radiotherapy consisting of at least 20 sessions.

The researchers found no long-term differences in outcomes between the groups – 95% of patients showed no symptoms of the disease five years after treatment. These cure rates are there equivalent in patients who have had their prostate surgically removed.

Early evidence suggests that stereotactic radiotherapy appears to be as effective, less burdensome, and less invasive than currently available treatment options.

Prostate cancer that has spread beyond its original site is unfortunate incurable in most cases. Treatment of this stage of the disease is aimed at stopping or controlling the cancer for as long as possible.

However, studies demonstrated that stereotactic radiotherapy can be used to treat disease that has spread to distant sites in patients with advanced prostate cancer. Researchers have found that stereotactic radiotherapy can free patients from clinically apparent disease for 8 to 13 months, delaying the need for hormone therapy or chemotherapy.

What are the side effects compared to other cancer treatments?

Stereotactic radiotherapy with painless radiation beams is performed every day. In the weeks after delivery, it is common to notice soreness and/or inflammation in the treated area. This reaches the level of requiring treatment one third of the cases.

Treatment for prostate cancer often affects erectile function because the nerves and blood vessels responsible for erection are often damaged.

Other recent research comparing stereotactic radiotherapy with surgery, it was found that 48% of patients treated with stereotactic radiotherapy had problems with sexual function two years after treatment compared with 75% of patients who underwent surgery.

What are the costs? Who can access it?

Newer AND more advanced Radiation therapy machines can provide more precise treatment, but they are much more pricey than standard machines. They also have more sophisticated maintenance and operational requirements.

However, classic radiation therapy devices can also be improved to provide stereotaxic precision.

Although the initial investment costs may be high, the cost-benefit ratio exercise show that stereotactic radiotherapy for lung cancer costs the healthcare system less than other cancer treatments and conventional radiotherapy. This is partly because treatment ends much faster. Formal cost-benefit analyzes have not been performed for prostate cancer, but they are likely to be similar.

Stereotactic radiotherapy is now widely available in most major Australian public hospitals for the treatment of many types of cancer, including selected lung cancers, kidney cancers, advanced brain cancers and bone cancers. This is at no cost to patients. It is also provided in many private centers.

However, even if a center can provide stereotactic radiotherapy, there is still significant variation in the equipment used to deliver this therapy.

Furthermore, the actual planning and delivery of radiotherapy is a sophisticated skill. Studies they showed that patients treated by clinicians with higher case volumes have better outcomes due to greater familiarity with these specialized techniques.

Over the past few years, radiotherapy departments around the world have rapidly expanded their capacity to provide stereotactic radiotherapy. Following the results of recent clinical trials, prostate cancer will most likely be added to the list of cancers treated in this way.