SAN DIEGO—Prostate cancer patients who are treated with a combination of androgen deprivation therapy (ADT) and radiotherapy may have a substantially improved chance of survival compared with patients who do not receive radiotherapy, according to British researchers. They reported at the 52nd annual meeting of the American Society for Radiation Oncology that combination therapy resulted in substantial benefits in overall survival and disease-specific survival in men with locally advanced prostate cancer.
“If the figures from the interim analysis are similar to the final analysis, we would expect a 43% reduction in the chance of death from prostate cancer in men with this regimen,” said lead study author Malcolm Mason, MD, who is professor of clinical oncology at the Cardiff University School of Medicine, Wales, United Kingdom. “This would translate into a reduction in the chance of deaths from prostate cancer in many thousands of men worldwide.”
From 1995 to 2005, 1205 men with high-risk prostate cancer in the United States, the United Kingdom, and Canada were randomly assigned to receive ADT alone or ADT plus radiotherapy. They were all followed for at least 6 years. Interim results presented at this meeting demonstrated there were no increased long-term side effects associated with the combination treatment.
Today, as most oncology pharmacists are aware, there is considerable variation in the treatment of men with localized, high-risk prostate cancer, and it is a hotly debated topic. Although the number of men treated with combined ADT and radiotherapy has increased in recent years, many patients are still treated with ADT alone. This multicenter, randomized trial examined the effects of external beam radiation therapy (EBRT) added to lifelong ADT.
“This study is practice changing, as it highlights the importance of radiation in the treatment of high-risk prostate cancer patients and clearly demonstrates its benefits,” said Mason in an interview with The Oncology Nurse -APN/PA. “It shows that the standard treatment for these patients should now be hormone therapy plus radiation.”
The type of radiation a man receives also makes a difference. Men with prostate cancer treated with intensitymodulated radiation therapy (IMRT) appear to have fewer gastrointestinal complications compared with patients treated with conventional three-dimensional conformal radiotherapy (3DCRT), according to a large, retrospective, observational study also presented at the meeting.
“Some of the most common side effects were rectal bleeding and diarrhea. We found that IMRT minimized the rates of bleeding and proctitis,” said lead study author Justin Bekelman, MD, who is a radiation oncologist at the University of Pennsylvania, Philadelphia, in an interview with The Oncology Nurse-APN/PA.
Using the Surveillance, Epidemiology and End Results–Medicare database, Bekelman’s team studied 12,598 men 65 years and older who were diagnosed with nonmetastatic prostate cancer between 2002 and 2004. The authors followed the patients through 2006 and identified complications that were serious enough to require invasive procedures (including surgery) and/or hospitalization.
The researchers found that among men who received IMRT, 18.8% had serious bowel complications during the 2 years after treatment compared with 22.5% of men treated with 3D-CRT.
3D-CRT uses imaging studies, including computed tomography, magnetic resonance imaging, and positronemission tomography scans to map the size, shape, and location of tumors and other organs in the area. IMRT is a more advanced version of 3D-CRT, offering a more targeted dose of radiation to the cancerous prostate gland. Although Medicare and private insurers typically cover both IMRT and 3D-CRT, little research has been conducted to show which treatment is associated with fewer side effects, an important consideration for men choosing among the various treatment options for the disease.
This new study showed that IMRT was associated with a reduction in proctitis and rectal bleeding. Urinary complications, such as cystitis and hematuria, did not significantly differ between the groups. No substantial differences were noted in the incidence of urinary or sexual side effects, such as erectile dysfunction; however, Bekelman noted that the study was limited to complications involving invasive surgical procedures. He noted that this study may not have captured the true prevalence of sexual side effects following treatment, for which patients may have sought less invasive remedies
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