Prostate Study: Reduced treatment time keeps moving organ in target field.

When we installed RapidArc, the 56-year-old prostate cancer patient was switched to from conventional IMRT radiotherapy to this more advanced method of treatment. The same dose was delivered to the prostate as with IMRT treatments, but the dose to such surrounding organs as the bladder and rectum was equal to or lower than that with IMRT.

On each day of treatment with RapidArc, there was a 4-minute savings in treatment time –down from 5½ minutes to 1½ minutes each day—and a significant savings in treatment time over the entire course of radiation therapy. Since the prostate typically is in constant motion (studies have shown that the longer the treatment lasts, the more the prostate moves), this faster delivery made a huge difference: the prostate did not have a chance to move out of the target treatment field. Overall patient comfort was also improved with the shorter treatment time.

A female lung cancer patient in her 90s had a large tumor in her right lung, located very close to her heart. Treatment needed to avoid the spinal cord and her healthy lung. Additionally the patient was extremely uncomfortable, and had trouble breathing as well as constant pain. She was barely able to tolerate the traditional course of treatment, which lasted for 5½ minutes per session.

RapidArc treatments to the lung lasted only 75 seconds compared to 5½ minutes with conventional IMRT treatments. The same dose of radiation (as previously given) was delivered to the tumor area, but the patient’s comfort was improved because she only had to stay still for a shorter period of time. More importantly, the doses received by the surrounding structures were much lower with RapidArc. The spinal cord dose was reduced by 30% and the dose to the healthy lung were lowered by almost 50%. The overall dose to the heart was also reduced significantly.

RapidArc™ radiotherapy technology, a major advance from Varian Medical Systems, is setting new standards in treatment for our patients. By shortening treatment times by as much as 8 times faster than current dynamic treatments, patients are not uncomfortable as long and radiotherapy can be more effectively delivered to organs prone to frequent movement such as the prostate. Furthermore, RapidArc means lower dosages to healthy surrounding areas of the body including vital organs.

Instead of treating tumors from many different angles, as with conventional IMRT (Intensity Modulated Radiation Therapy), RapidArc treatment is given in one continuous arc. The shape of the treatment field and amount of dose changes to conform to the tumor volume while avoiding critical nearby body areas.