prostate news

Prostate cancer therapy can increase heart risk factors

DALLAS, Feb. 1, 2010 — Androgen-deprivation therapy (ADT), commonly used to treat prostate cancer, can worsen heart risk factors and may increase the risk of heart attack and/or cardiac death, although the relationship between ADT and heart attack or cardiac death has not been definitively established, according to a science advisory published in Circulation: Journal of the American Heart Association and CA: A Cancer Journal for Clinicians.

The advisory, produced by a writing group of experts from the American Heart Association, American Cancer Society and American Urological Association, and endorsed by the American Society for Radiation Oncology, is an evaluation of published research about the relationship between ADT and cardiovascular events and risk factors in patients with prostate cancer.

Considerable data show that ADT can increase fat mass, increase low-density lipoprotein (LDL) cholesterol—the “bad” cholesterol—and cause blood sugar abnormalities, according to the writing group.

“Based on current data, it was appropriate to conclude that there may be a relationship between ADT therapy in patients with prostate cancer and future cardiovascular risk,” said Glenn N. Levine, M.D., chair of the advisory writing group and professor of medicine at Baylor College of Medicine in Houston.

While some studies have found an association between ADT and increased cardiovascular risk, other studies have not detected the association, according to the advisory. The writing group called for future studies to prospectively analyze heart risks related to ADT whenever possible.

An increased risk with ADT was noted in 1 percent to 6 percent of the study populations. Thus, “while there may be some increased heart risk, the decision about whether to initiate ADT should be based on weighing the benefits of therapy with this potential modest risk,” he said.

Decisions about ADT should be made by the physician treating the patient for prostate cancer without referral to other specialists, according to the advisory. However, given the metabolic effects of ADT therapy, patients receiving ADT should be followed periodically by their primary care physicians.

Patients with known heart disease should always be encouraged to adopt healthy lifestyle changes and receive the appropriate preventive therapies if necessary, including lipid-lowering, blood pressure-lowering, glucose-lowering therapy and antiplatelet therapies (such as aspirin), Levine said.

Co-authors include: Anthony V. D’Amico, M.D., Ph.D.; Peter Berger, M.D.; Peter E. Clark, M.D.; Robert H. Eckel, M.D.; Nancy L. Keating, M.D., M.P.H.; Richard V. Milani, M.D.; Arthur I. Sagalowsky, M.D.; Matthew R. Smith, M.D., Ph.D.; and Neil Zakai, M.D.

Author disclosures are on the manuscript.

IGRT May Improve Outcomes for Obese Prostate Cancer Patients

September 2, 2009—Moderately to severely obese prostate cancer patients may have improved treatment outcomes when treated with image-guided radiation therapy (IGRT) over traditional external beam radiation therapy (EBRT) because IGRT corrects for prostate shifts, which, if not planned for, can lead to incorrect doses of radiation to the disease site, according to a study in the September 1 issue of the International Journal of Radiation Oncology*Biology*Physics, the official journal of the American Society for Radiation Oncology (ASTRO).

Several studies have suggested that obesity can lead to higher rates of clinical recurrence or biochemical failure rates in prostate cancer patients receiving EBRT. Researchers at the Carol G. Simon Cancer Center, Morristown Memorial Hospital in Morristown, N.J., and the Uematsu-Atsuchi-Serendipity Oncology Center in Terukuni, Kagoshima, Japan, sought to determine if these failure rates were caused by the treatment modality used rather than strictly the fact that the patients were obese.

Researchers found that moderately to severely obese prostate cancer patients (i.e., with a body mass index of greater than 35) do have larger prostate shifts during treatment, which can lead to radiation treatments not being delivered to the same spot every day, potentially compromising the treatment. The percentage of moderately to severely obese patients with a left to right shift of greater than 10 millimeters was 21.2 percent compared to only 1.3 percent for patients of a normal weight.

IGRT is a new type of radiation therapy that uses normal EBRT guided by imaging, such as CT scans, ultrasound or X-rays taken in the treatment room just before the patient is given radiation on a daily basis. All patients receive imaging scans as part of the planning process. However with IGRT, doctors are able to compare the earlier images with those taken before each treatment to adjust the dose if necessary.

Researchers determined that the radiation treatment modality used does impact outcomes. IGRT allows for correction of target displacements from the planned position before radiation delivery begins, so shifts may be corrected easily and thus may lead to improved control rates for obese prostate cancer patients.

“All patients deserve the treatment that is going to give them the best chance at cure and survival,” James R. Wong, M.D., lead author of the study and chair of radiation oncology at Morristown Memorial Hospital, said. “With the results of this study, we now know that obese patients have a unique complication when it comes to planning their treatment but that we can try to correct it simply by using IGRT instead of EBRT. I encourage overweight men and their families to talk to their doctors about IGRT when considering their treatment options.”

ASTRO is the largest radiation oncology society in the world, with more than 10,000 members who specialize in treating patients with radiation therapies. As the leading organization in radiation oncology, biology and physics, the Society is dedicated to improving patient care through education, clinical practice, advancement of science and advocacy. For more information on radiation therapy, visit www.rtanswers.org. To learn more about ASTRO, visit www.astro.org.

Weight Gain in Adulthood Associated with Prostate Cancer Risk; Patterns Differ by Ethnicity

• Overweight by age 21 linked to lower risk of localized, low-grade prostate cancer
• Overweight in older adulthood linked to increased risk of prostate cancer
• Risk varied across ethnic groups

September 1, 2009 – Body mass in younger and older adulthood, and weight gain between these periods of life, may influence a man’s risk for prostate cancer. This risk varies among different ethnic populations, according to results of a study in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.

“The relationship of certain characteristics, such as body size, with cancer risk may vary across ethnic groups due to the combined influence of both genes and lifestyle,” said lead researcher Brenda Y. Hernandez, Ph.D., M.P.H., assistant professor at the Cancer Research Center of Hawaii, University of Hawaii.

Obesity is a risk factor for common cancers like colorectal cancer and breast cancer in post-menopausal women. However, the influence of body size on prostate cancer risk is not entirely understood. Hernandez and colleagues examined this relationship in a multiethnic population consisting of blacks, Japanese, Hispanics, Native Hawaiians and whites, and compared differences among age groups. They used the Multiethnic Cohort, a longitudinal study of men aged 45 to 75 years old established in Hawaii and California from 1993 to 1996.

Results showed that of the 83,879 men who participated in this study, 5,554 were diagnosed with prostate cancer. Overall, men who were overweight or obese by age 21 had a decreased risk of localized and low-grade prostate cancer, according to Hernandez.

Being overweight in older adulthood was associated with increased risk of prostate cancer among white and Native Hawaiian men, but a decreased risk among Japanese men. Excessive weight gain between younger and older adulthood increased the risk of advanced and high-grade prostate cancers in white men and increased the risk of localized and low-grade disease in black men, but decreased the risk of localized prostate cancer in Japanese men.

“Readers of Cancer Epidemiology, Biomarkers & Prevention might initially look at these results and discount them for being inconsistent across the racial/ethnic groups, but they should not,” said Elizabeth A. Platz, Sc.D., M.P.H., associate professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health, Baltimore.

Platz stressed the strengths of this study, including that it was conducted prospectively and consisted of large numbers of men in most of the ethnic groups studied. An estimated 30 percent of prostate cancer cases occurred among Japanese men (n=25,275), 25 percent among white men (n=21,311), 27 percent among Hispanic men (n=20,448), 13 percent among black men (n=10,934), and 7 percent among Native Hawaiian men (n=5,921).

“There is no reason to think that the differences in results by ethnicity are explained by bias. Different racial and ethnic populations tend to have differing proportions of fat relative to lean mass and carry their fat mass differently. These differences may be used as a launching point for the next line of research: The nature of the weight gain — amount of fat gained and distribution of the fat gained in association with prostate cancer risk overall, and by stage and grade,” added Platz, who is also an editorial board member for Cancer Epidemiology, Biomarkers & Prevention.
This study underscores the importance of investigating cancer etiology in diverse populations and researchers should conduct additional studies.

“These results do not warrant a change in the current public health messages about obesity: Men of normal weight in all racial/ethnic groups should be encouraged to avoid weight gain and men who are overweight and obese should be encouraged to lose weight for good health in general,” Platz added.