Randal H. Henderson, MD, MBA, professor, Department of Radiation Oncology, associate medical director, University of Florida Health Proton Therapy Institute, discusses accessibility of proton therapy versus intensity-modulated radiation therapy (IMRT) in prostate cancer.

Compared with IMRT, proton therapy is not as widely available and more expensive. Many insurance companies will not pay for protons because they require more data to justify paying the extra cost, explains Henderson. A recently opened PCORI-funded trial at the University of Florida Health Proton Therapy Institute has potential to show that protons are as effective, if not better, in terms of controls rates and toxicity compared with IMRT, says Henderson.

If the results for IMRT and proton therapy are equitable, it could potentially help the cost issue facing proton therapy, which is tied to how long it takes to deliver the treatment, according to Henderson. Insurance companies could make proton therapy more widely available to their insured populations and expand access to protons across the United States, concludes Henderson.

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Randal H. Henderson, MD, MBA, discusses accessibility of proton therapy versus intensity-modulated radiation therapy in prostate cancer.

Dr. Henderson on Accessibility of Proton Therapy in Prostate Cancer

Randal H. Henderson, MD, MBA, professor, Department of Radiation Oncology, associate medical director, University of Florida Health Proton Therapy Institute, discusses anticipated developments with radiotherapy in prostate cancer. 

There is a lot of interest in shortening the duration of radiotherapy, says Henderson. Investigators are actively looking at 4 weeks of treatment versus the traditional 8 weeks. The use of proton therapy would allow patients to undergo shorter schedules and spare the normal tissues better than intensity modulated radiation therapy (IMRT) could.

SpaceOAR hydrogel has also emerged as a way to help protect the rectum from high-dose injury that can occur with protons or IMRT. Instead of having the rectum right behind the prostate and having the anterior rectal wall being exposed to the high-dose area, a needle could be placed between the anterior rectal wall and the prostate. By opening that area up with some saline and placing the hydrogel into that space, it helps hold the anterior rectal wall further from the prostate.

Then, protons or IMRT could be used to get the anterior rectal wall out of the exposure field, explains Henderson; that has essentially eliminated any resulting rectal bleeding and ulceration. Although SpaceOAR is not yet widely available, it could become an effective way to improve the results of existing technology, he concludes.

Randal H. Henderson, MD, MBA, professor, Department of Radiation Oncology, associate medical director, University of Florida Health Proton Therapy Institute, discusses anticipated developments with radiotherapy in prostate cancer.

Dr. Henderson on Anticipated Developments With Radiotherapy in Prostate Cancer

Randal H. Henderson, MD, MBA, professor, Department of Radiation Oncology and associate medical director at the University of Florida Health Proton Therapy Institute, discusses the potential benefits of proton therapy versus intensity-modulated radiation therapy (IMRT) in prostate cancer.

Proton therapy and IMRT damage cancer cells differently, says Henderson. Single-stranded DNA breaks typically result from IMRT, while double-stranded DNA breaks occur more frequently with proton therapy, as protons are heavy charged particles. These complex, double-stranded breaks are more difficult for cancer cells to repair, he adds. As such, dose-for-dose, proton therapy may yield a greater amount of cancer cell death than IMRT.

In Henderson’s experience, the control rates seen in patients with intermediate- and high-risk disease who were treated with proton therapy are better than rates observed in patients treated with IMRT in trials conducted at Memorial Sloan Kettering Cancer Center.

A trial funded by the Patient-Centered Outcomes Research Institute is now open and will accumulate 3,000 patients and allow investigators to compare the 2 therapies. Nearly all the proton facilities in the country—and many academic centers that do not have protons&mdash;will participate.

Randal H. Henderson, MD, MBA, professor, Department of Radiation Oncology and associate medical director at the University of Florida Health Proton Therapy Institute, discusses the potential benefits of proton therapy versus intensity-modulated radiation therapy in prostate cancer.

Dr. Henderson on Proton Therapy Versus IMRT in Prostate Cancer

Randal H. Henderson, MD, MBA, professor, Department of Radiation Oncology, associate medical director, University of Florida Health Proton Therapy Institute, discusses the benefits of proton therapy in prostate cancer.

More normal tissue can be spared with proton therapy as compared with traditional intensity-modulated radiation therapy (MRT), says Henderson. Additionally, patients who undergo proton therapy are spared unnecessary doses of radiation to their bladder or rectum and thus, added complications. Notably, rectal complications have been linked with the amount of rectum that is exposed to radiation, adds Henderson.

Two types of injury can occur from radiation therapy; these injuries are dependent on the dosage of radiation received. For example, high doses of radiation can result in rectal bleeding and ulcerations. Both proton therapy and IMRT treat a small area of the anterior rectal wall at high intensity, notes Henderson. However, the 2 approaches diverge in the expanse of the remainder of the rectum treated. Protons completely spare the posterior part of the rectal wall whereas IMRT treats the entire circumference of the rectal wall, explains Henderson.

Randal H. Henderson, MD, MBA

Articles

Dr. Henderson on Accessibility of Proton Therapy in Prostate Cancer

Dr. Henderson on Anticipated Developments With Radiotherapy in Prostate Cancer

Dr. Henderson on Proton Therapy Versus IMRT in Prostate Cancer

Dr. Henderson on the Benefits of Proton Therapy in Prostate Cancer