3D-Conformal Cuts Complications of Radiation Therapy for Early Stage Prostate Cancer Patients

With proper equipment and strict quality control, can be done at community hospitals,study says

Boston, MA /PSA Rising, NYC/ October 25, 2000 -- Radiation oncologists can increase the dose of radiation and still lower the rate of complications if they use 3D conformal radiation therapy (3D-CRT) when treating patients with early stage prostate cancer, a new study presented shows.

Earlier studies have indicated that increased doses would increase cure rates, says Jeff Michalski, M.D., at Washington University School of Medicine, St. Louis, MO. But, he says, "we were concerned that as the dose was increased, complication rates would also increase - maybe not right after treatment, but several months and several years later."

This study found that 396 patients, even three years after treatment, had the same or fewer complications than those who were treated with standard external beam radiation therapy, Dr. Michalski says. He presented results in Boston October 25 at the annual American Society for Therapeutic Radiology and Oncology annual meeting.

One way of measuring radiation doses is by the Gy, or "Gray" (name of the man who invented this measure). Standard radiation doses for prostate cancer range between 66.6 Gy and 70 Gy, says Dr. Michalski. One hundred eleven patients received 68.4 Gy, 274 patients received 73.8 Gy.

Only one patient treated to 68.4 Gy suffered a grade-three complication (a complication that requires hospitalization, surgery or medical intervention for six months or longer). "That compares to the 18 we would have expected to see with standard external beam radiation therapy," says Dr. Michalski.

Three patients treated to 73.8 Gy suffered a grade-three complication compared to an expected 42, Dr. Michalski adds.

The results haven't been fully analyzed for patients treated to 79.2 Gy. It looks like there is no increase in complication rates in this group either, says Dr. Michalski.

In addition, this study found that 3D-CRT can be done, and done well, in the community hospitals/centers not just at academic hospitals/facilities, notes Dr. Michalski. This study was conducted as a Radiation Therapy Oncology Group (RTOG) clinical trial at 40 institutions across the U.S.

RTOG outlined very specific quality controls that needed to be met at the institutions, he says. Those quality controls are essential in treating with 3D-CRT Dr. Michalski says.

Dr. Michalski presented the data at the American Society for Therapeutic Radiology and Oncology annual meeting, October 25 in Boston, MA.

Related Stories and Links

A 1999 study at Memorial Sloan Kettering, NYC compared three-dimensional conformal radiation therapy (3D CRT) to intensity modulated radiation therapy (IMRT) for patients with early stage prostate cancer. IMRT Accurately Delivers Radiation to Early Prostate Cancer, Lowers Risk of Rectal Bleeding Radiation Oncology Technique - Palo Alto Medical Foundation PAMF Prostate Cancer Resource Site A brief account of the differences between 3D-CRT and IMRT is at Nomos (an equipment manufacturer) What is IMRT? Abstract of a recent UK study comparing conformal and standard (old-style) radiation: Lancet 1999 Jan 23;353(9149):267-72 Comparison of radiation side-effects of conformal and conventional radiotherapy in prostate cancer: a randomised trial. Dearnaley DP, et al, Royal Marsden NHS Trust and the Institute of Cancer Research, Sutton, Surrey, UK.

This page last modified 26 October 2000