Posts Tagged ‘incident’

Bisphosphonates for osteoporosis not associated with reduced breast cancer risk, study suggests

Some studies have suggested that bisphosphonates, which are commonly used to treat osteoporosis, may have antitumor and antimetastatic properties. Some observational studies have suggested bisphosphonates may protect women from breast cancer.

The authors analyzed the relationship of postmenopausal breast cancer and bisphosphonate use by examining data from two randomized, double-blind, placebo-controlled trials. The Fracture Intervention Trial (FIT) randomly assigned 6,459 women (ages 55 to 81 years) to alendronate or placebo with an average follow-up of 3.8 years. The Health Outcomes and Reduced Incidence with Zoledronic Acid Once Yearly-Pivotal Fracture Trial (HORIZON-PFT) randomly assigned 7,765 women (ages 65 to 89 years) to annual intravenous zoledronic acid or placebo with an average follow-up of 2.8 years. The authors compared rates of breast cancer in the bisphosphonate treatment groups to the placebo groups.

There was no significant difference in breast cancer rates between the bisphosphonate and placebo groups. In FIT, the breast cancer rate was 1.5 percent in the placebo group and 1.8 percent in the alendronate group. In HORIZON-PFT the rate was 0.8 percent in the placebo group and 0.9 percent in the zoledronic acid group. There also was no significant difference when data from the two trials were combined.

“These data provide evidence that three to four years of treatment with bisphosphonate, alendronate or zoledronic acid, therapy does not reduce the risk of incident breast cancer in postmenopausal women. The discrepancy between our results and the reports of associations in observational studies may be an example of indication bias and illustrates the limitation and hazard of drawing conclusions about treatment effects from observational studies (even those that are very well done) and emphasizes the value of confirming such associations in randomized trials. The effect of bisphosphonate treatment on breast cancer risk in nonosteoporotic populations should be investigated in other randomized trials.”

In a related editor’s note, Joseph S. Ross, M.D., M.H.S., a JAMA Internal Medicine associate editor, writes: “Whereas these findings highlight why it is so important for new therapies to be evaluated using RCTs (randomized clinical trials), they also reinforce the importance of assessing the methodological rigor of observational studies before interpreting real-world effects.”

“Just as we closely scrutinize RCT design, so must we understand the quality and statistical power of the data used for observational studies, how participants were identified, the duration of follow-up, the end points examined, and the analytical strategy used. Observational studies are particularly valuable for clinical situations unlikely to be tested using RCTs, and many provide valid and reliable real-world evidence,” Ross continues.

“Thus, whereas we all can remember examples of when RCTs and observational studies differed, less memorable are the even more numerous examples in which results were consistent. In the end, we should be open to all types of evidence and rely on rigorous clinical science to guide practice,” Ross concludes.

source : http://www.sciencedaily.com/releases/2014/08/140811170108.htm

Special camera detects tumors

Tumor removal surgeries pose a great challenge even to skillful and experienced surgeons. For one thing, tumor margins are blending into healthy tissue and are difficult to differentiate. For another, distributed domains of cancer and pre-malignancies are difficult to recognize. Up to now, doctors depend exclusively upon their trained eyes when excising pieces of tumors. In future, a new special camera system can help visualize during operation even the smallest, easy-to-overlook malignant pieces of tumor and thereby support the surgeons during complicated interventions.

The trick: the camera can display fluorescent molecules that "paint" the cancer tissue. These are injected into the patients blood circulation prior to the operation and selectively attach onto the tumor during their trip through the body. If the corresponding area is then illuminated with a specific wavelength, fluorescence is emitted and the malignant tissue glows green, blue, red, or any other color, depending on the injected dye, while the healthy tissue appears the same. In this way, the surgeon can see clasters of tumors cells that cannot be recognized by the naked eye.

New system reveals several dyes simultaneously

Researchers at the Fraunhofer Project Group for Automation in Medicine and Biotechnology (PAMB), which belongs to the Fraunhofer Institute for Manufacturing Engineering and Auto- mation (IPA), have developed a new surgical aid, a multispectral fluorescence camera system. In the future, this special camera will integrate into various medical imaging systems such as, surgical microscopes and endoscopes, etc. The scientists from Mannheim, Germany, will make the debut of a prototype of this high-tech system at the Medica Trade Fair in Düsseldorf in the joint Fraunhofer booth (Halle 10, Booth F05) between 20-23 November. The novel aspect about this camera: it can display several fluorescent dyes and the reflectance image simultaneously in real time — systems available until now have not been able to achieve this. The advantage: arteries and delicate nerves that must not be injured during an intervention can likewise be colored with dye. They too can then be detected with the new camera, since they are set apart from their surroundings.

"The visibility of the dye to the camera depends in large part on the selection of the correct set of fluorescence filters. The filter separates the incident excitation wave- lengths from the fluorescing wavelengths so that the diseased tissue is also set apart from its surroundings, even at very low light intensities," says Nikolas Dimitriadis, a scientist at PAMB. The researchers and their colleague require only one camera and one set of filters for their photographs, which can present up to four dyes at the same time. Software developed in-house analyses and processes the images in seconds and presents it continuously on a monitor during surgery. The information from the fluores- cent image is superposed on the normal color image. "The operator receives significantly more accurate information. Millimeter-sized tumor remnants or metastases that a surgeon would otherwise possibly overlook are recognizable in detail on the monitor. Patients operated under fluorescent light have improved chances of survival," says Dr. Nikolas Dimitriadis, head of the Biomedical Optics Group at PAMB.

In order to be able to employ the multispectral fluorescence camera system as adapt- ably as possible, it can be converted to other combinations of dyes. "One preparation that is already available to make tumors visible is 5-amino levulinic acid (5-ALA). Physicians employ this especially for glioblastomas — one of the most frequent malig- nant brain tumors in adults," explains Dimitriadis. 5-ALA leads to an accumulation of a red dye in the tumor and can likewise be detected with the camera. The multispectral fluorescence imaging system should have passed testing for use with humans as soon as next year. The first clinical tests with patients suffering from glioblastomas are planned for 2014.

source : http://www.sciencedaily.com/releases/2013/11/131107103527.htm