July 07 Newsletter Articles

Prostate Cancer Diagnosis Usually Does Not Mean Shorter Lifespan

Good news for men diagnosed with prostate cancer:

The vast majority of men diagnosed today will live as long as their counterparts who do not have the disease. This is the conclusion from an analysis of data from the Surveillance, Epidemiology, and End Results (SEER) program, a huge national database of cancer statistics.

The researchers examined 5- and 10-year survival data for 183,484 men diagnosed with prostate cancer between 1990 and 2000. They found that the overall 5-year survival rate for prostate cancer patients was 99%; 10-year survival was 95%. Compared with men in the general population, those with prostate cancer had an excess mortality of only 1% at 5 years and 5% at 10 years.

The researchers noted that two-thirds of the men were diagnosed with well-differentiated or moderately differentiated localized/regional cancers. Among these men, there was no increased mortality compared to men in the general population.

Prostate cancer experts continue to debate whether widespread prostate specific antigen (PSA) screening is responsible for lower mortality rates. However, most men diagnosed in the PSA era do not experience excess mortality. This finding should be comforting for men who are living with a prostate cancer diagnosis.

JOURNAL OF CLINICAL ONCOLOGY Volume 23, Page 441 January 20, 2005

NEW RESEARCH

Prostate Cancer Screening Is Less Accurate In Men Who Are Obese

Men who are obese produce lower levels of prostate specific antigen (PSA), according to results of a new study. These low PSA levels may allow some cancers to go undetected in these men.

The study was conducted with 2,779 men who were participating in the National Cancer Institute's Early Detection Research Network. The researchers correlated body mass index (BMI) with PSA level. (A BMI of 30 is the cutoff point for obesity and is the equivalent of a 6-foot tall man who weighs 221 pounds.) They found that as BMI increased, PSA level decreased. Normal weight men had an average PSA value of 1.01 ng/dL. For obese men, the average PSA was 0.69 ng/dL.

The study results suggest that a low PSA level in obese men may mask the presence of prostate cancer, providing false reassurance about the absence of prostate cancer. The direct relationship found between increasing BMI and decreasing PSA also suggests that PSA levels may be inappropriately low in men classified as overweight but not quite obese (BMI of 25-29, or 184-213 pounds for a 6-foot tall man). One explanation for the findings is that higher estrogen levels in overweight men may lead to lower PSA levels.

CANCER
Volume 103, Page 1092
March I, 2005

PROSTATE CANCER PATIENT SUPPORT 1 800 80 Us TOO

EXCELLENT RESULTS WITH IMPLANTED RADIATION SEEDS IN EARLY PROSTATE CANCER

A technique implanting radiation seeds the size of a grain of rice directly into the prostate gland yields "excellent long-term results" for treating early prostate cancer concludes a new analysis of pooled data.

This technique of implanting radiation seeds became an established treatment option for early-stage prostate cancer after positive long-term results were reported from several centers in the United States. Now, the pooled data from 11 institutions, following 2693 patients for 5 to 8 years, "again demonstrate that excellent long-term results are achieved with this treat- ment intervention," researchers conclude in the February issue of the International Journal of Radiation Oncology, Biology, Physics (Vol. 67, pp. 327-33, 2007).

In patients whose implant quality was deemed ideal based on postimplantation dosimetric evaluation, the biochemical relapse-free survival at 8 years exceeded 90%, the researchers report. The biochemical measure was prostate specific antigen (PSA), and a PSA relapse was defined according to the American Society for Therapeutic Radiology and Oncology (ASTRO) as 3 successive PSA rises after posttreatment nadir was achieved. Also at 8 years, 74% of men were free of distant metastases and 69% were free of clinical disease.

"This study is exciting because it shows that brachytherapy alone without additional surgery, radiation, or drugs can be effective at curing early-stage prostate cancer," says lead author Michael Zelefsky, MD, from the Memorial Sloan-Kettering Cancer Center, in New York. Although there are some moderate urinary adverse effects with the implant, these generally resolve in the first few months, he added.

Two isotopes were used over the 10-year time frame 1 iodine 1251 at a median dose of 144 Gy or palladium ¡3Pd at 130 Gy. Which isotope was used did not have a significant impact on the outcomes, the authors note. The only controllable factor to affect long-term outcome was the dose of radiation delivered, which is a reflection of implant quality, the authors comment.

Significantly better outcomes were seen with higher doses. With the iodine isotope, the 8-year PSA-relapse survival was 93% in patients who received higher doses of radiation compared with 76% in patients who received lower doses of radiation. With the palladium isotope, the 5-year PSA relapse-free survival was 92% in patients who received higher doses of radiation com- pared with 83% for those with lower doses.

The PSA nadir (lowest value post-treatment), measured at 3 years after implantation, was also associated I with long-term outcome. Best results were seen in men having a PSA nadir < 0.5 ng/mL. The relatively low nadir PSA values reflect the high intraprostatic doses that are delivered with permanent seed implantation.

Medscape Medical News, 8 February 2007