Study Reveals Why Obese Men Have Lower PSA Readings
North American researchers conducting a retrospective multi-institution study have found what they consider the likely explanation for two anomalies: (1) the common observation that men with a higher body mass index (BMI) tend to have lower prostate specific antigen (PSA) readings; and (2) recent results linking obesity with more aggressive prostate disease.
New results conclude that the critical factor is "hemodilution " - a phenomena where the greater volume of blood in bigger men lowers PSA readings by diluting the concentration of the PSA protein, which is believed to enter the bloodstream when the prostate enlarges. Though the findings need to be confirmed in prospective studies, the researchers believe that hemodilution could also compromise evaluation of other circulating disease markers in high-BMI patients.
More than 13,600 patients had radical prostatectomies at Duke Prostate Center, Johns Hopkins Hospital, or 5 Veterans Administration medical centers between 1988 and 2006. All had reliable measurements taken of their BMI and PSA. Using statistical methods, researchers were able to calculate how much blood each patient had, how much actual PSA protein (mass) was present, and thus the PSA concentration. Men with a BMI over 35 (30 and above is obese) had 21-23 percent more blood and 11-21 percent lower PSA concentrations than men of normal weight, without, in most cases, statistically significant increases in the mass of circulating PSA protein.
The work was published in the November 21 Journal of the American Medical Association by Dr. Stephen Freedland of Duke University Medical Center and colleagues from more than a dozen participating centers and institutions. "For these other tests [looking for biomarkers of cancer and other diseases] just starting down the pipeline, " he says, "we need to think of the total amount of a biological marker rather than concentration."
Lung Cancer Patients Report Chemo Side Effects Online
Researchers at Memorial Sloan-Kettering Cancer Center have tested a Web-based system that allows cancer patients to report chemotherapy side effects to their clinicians in real time. The results appear in the December 1 Journal of Clinical Oncology.
During a median 42-week period, 107 English-speaking patients, most of whom were over age 50, were able to use an online platform called Symptom Tracking and Reporting to log and grade physical, mental, and quality-of-life side effects while undergoing treatment for thoracic cancer, predominantly metastatic non-small-cell lung cancer. Patients typically entered their information at computer kiosks in the waiting area of their treatment clinic, though some used a home computer. Clinicians received these reports soon after and were free to follow up according to their judgment.
Patients adhered to the protocol fairly well throughout the study, regardless of age, sex, or disease severity. The only factor tied to adherence was previous experience with computers. Most often, reported barriers to using the system were insufficient time and not being reminded to use it. Nearly all of the patients said they found the system easy to use, wished to continue using it, and would recommend it to others.
If patients receive reminders and validation that the information they submit is truly useful to clinicians, then self-reporting programs such as these may improve efficiency in both clinical research and routine care settings by encouraging patients to follow their treatment regimens, improving the accuracy of toxicity data collection, expediting patient management, and decreasing avoidable hospitalizations, note the authors. The tradeoff, however, is that "between-visit reporting may increase work-burden by generating information that must be reviewed or acted upon."
Elasticity of Cells Could Be a Marker for Cancer
Cancer cells tend to be much softer, or more elastic, than normal cells, and measuring this characteristic on the nanometer scale could be another way to diagnose cancer. Dr. James Gimzewski of the California NanoSystems Institute, collaborating with Dr. Jian Yu Rao of UCLA' Jonsson Comprehensive Cancer Center, profiled the elasticity of live metastatic cancer cells and normal cells from patients' body fluids using atomic force microscopy. The researchers could distinguish between normal and cancerous cells based on their physical characteristics, according to findings published online December 2 in Nature Nanotechnology.
"Measuring the physical features of cancer cells adds another dimension to the analysis of these cells and could help us diagnose the disease, " says Dr. Rao. Unlike normal cells, cancer cells are more flexible and can move through holes and spaces easily, which is how they enter the bloodstream and spread to other organs, according to Dr. Rao. "This is a major reason cancer is so deadly, " he adds.
The researchers tested fluids from patients with suspected metastatic lung, breast, or pancreatic cancer. Each patient sample contained both normal and cancerous cells, allowing the researchers to directly compare the physical characteristics of the cells. The cancerous cells were found to be more than 70 percent softer than the benign cells, based on measurements of cell stiffness at the nanometer scale. The cancerous cells showed a similar physical signature that was distinct from normal cells, even though the patients had different tumor types.
Intensive Quitline Counseling, Free NRT Help More Quit Smoking
The largest randomized trial of its kind has shown that offering more intensive tobacco quitline services, including longer phone counseling sessions and free nicotine replacement therapy (NRT), is a highly effective - and cost-effective - way to help smokers quit.
Published in a special supplement on quitlines in the December 2007 Tobacco Control and partially funded by NCI's Tobacco Research Initiative for State and Community Interventions, the trial was led by researchers from the Kaiser Permanente Center for Health Research in Portland, Oregon.
The trial included 4,600 smokers who called the Oregon tobacco quitline. Callers were randomly assigned to receive one of six types of services: three different types of phone counseling approaches (brief, moderate, or intensive), each with or without free NRT. The most effective approach was the intensive counseling plus free NRT, which helped more than 21 percent of the smokers quit. In comparison, less than 12 percent of smokers quit in the brief counseling with no free NRT arm. The research team defined quitting as no use of any form of tobacco for at least 30 days at the 12-month follow-up.
Callers' satisfaction with the quitline services were far higher in the intensive counseling/NRT arm compared with the brief counseling/no NRT arm (92.5 percent vs. 53.9 percent), although the cost per participant was nearly four times higher, $268 vs. $67, respectively.
"However, our results suggest that higher quit rates, greater client satisfaction, and the potential to attract more smokers to quitlines more than offset the modest additional costs, " said the study' lead author, Dr. Jack Hollis. "Heavily addicted smokers, who have the highest health care costs over time, may benefit even more from intensive counseling and medication."