March 4, 2008, 5:38 PM CT

PET/CT planning beneficial for head and neck cancer patients

Using a combination of positron emission tomography (PET) and computed tomography for radiation treatment therapy planning in head and neck carcinoma patients provides for excellent, local and regional disease control when in comparison to CT alone, as per a research studyin the March 1 issue of the International Journal for Radiation Oncology*Biology*Physics, the official journal of the American Society for Therapeutic Radiology and Oncology.

CT has been the traditional choice for staging and radiation treatment therapy planning for head and neck squamous cell carcinomas, which account for approximately 5 percent of malignancies worldwide; but PET has been shown to have advantages over CT and other imaging modalities in detecting primary tumors, involved lymph nodes and distant metastatic disease not clearly otherwise identified. PET alone does have several disadvantages though, such as poor related to precise anatomic structures, but these negative impacts are significantly reduced when PET and CT are combined by fusing the separate scans taken on a hybrid scanner.

While it has been proven in several studies that PET/CT imaging is feasible for head and neck radiation treatment planning, very few studies have been done to determine the clinical outcomes. So, scientists in the departments of Radiation Oncology, Radiology, Neoplastic and Related Disorders, and Otolaryngology at the Medical College of Wisconsin in Milwaukee conducted this study to evaluate the clinical outcomes, including overall survival, disease-free survival and the occurence rate of recurrence of patients receiving PET/CT-guided radiation treatment and the correlation of the clinical outcomes to the maximum standard uptake value obtained on the PET scan......... Posted by: Andria      Read more         Source

March 2, 2008, 8:41 PM CT

Arsenic aids tumor imaging

Arsenic associated with a drug that binds to the blood vessels of malignant tumors provides a powerful imaging agent that could one day allow physicians to detect hard-to-find tumors and more closely monitor cancers response to treatment, scientists at UT Southwestern Medical Center have found.

The findings, based on animal studies and appearing in todays issue of Clinical Cancer Research, mark the first time arsenic has been used to label antibodies for the detection of tumors.

Dr. Philip Thorpe, professor of pharmacology at UT Southwestern and senior author of the study, helped create the cancer drug called bavituximab, an antibody that homes in on a specific molecular target on the blood vessels that feed tumors. Bavituximab is being tested in clinical trials to treat solid-tumor cancers in combination with chemotherapy.

While arsenic has been used as a poison for centuries, the dose of arsenic needed for imaging tumors is about one-millionth of that needed to cause toxicity, Dr. Thorpe said.

Arsenic-labeled bavituximab appears to be safe.

In the study, Dr. Thorpe and colleagues injected radioarsenic-labeled bavituximab into rats with prostate tumors. When the bavituximab bound to its target on the the tumor blood vessels, the tag-along arsenic created a hot spot that scientists then imaged using positron emission tomography methods. The radioactivity levels produced by the arsenic are comparable to those used in standard, routine imaging procedures in humans. The technique allowed them to locate and capture uncommonly clear images of the tumors. They also discovered that there was little or no detectable uptake of bavituximab by normal organs, including the liver, a common site where drugs become entrapped......... Posted by: Andria      Read more         Source

February 25, 2008, 9:26 PM CT

Chemo holidays for men with advanced prostate cancer

The double-blind, randomized study, led by principal investigator Tomasz Beer, M.D., recently was reported in the journal Cancer. Beer is the Grover C. Bagby Endowed Chair for Cancer Research, director of the OHSU Cancer Institute Prostate Cancer Program, and associate professor of medicine (hematology/medical oncology), OHSU School of Medicine.

Beer and his team wanted to know if men with metastatic, androgen-independent prostate cancer cancer that has spread from the prostate and is not affected by the male hormone, androgen could take a break from docetaxel, an intravenous chemotherapy delivery drug that is the gold standard therapy for androgen-independent prostate cancer. Docetaxel works by killing cancer cells and slowing cell growth. However, the drug also can cause side effects, such as hair loss, nausea, loss of appetite and increased chance for infections. Chemo holidays can be a much-needed vacation from these side effects.

Previous to this study, it wasnt known whether stopping chemotherapy would lead to therapy resistance.

We wanted to see if we could improve the quality of life for these patients by giving them time away from chemotherapy and possibly extend the time their cancer is controlled. Essentially, what we proved is that in selected subjects, chemotherapy holidays are feasible and provided meaningful breaks from therapy, said Beer......... Posted by: Andria      Read more         Source

February 14, 2008, 10:22 PM CT

Single reader with CAD more efficient

Single reading of screening mammograms with computer-aided detection (CAD) is more efficient than double reading and yields a higher sensitivity than the first reader in a double reading program, according to a study conducted by researchers at Charlotte Radiology in Charlotte, NC. In addition, the readings with CAD had a significantly lower recall rate than double reading.

The double reading method consisted of the mammogram being first read by sub-specialized mammographers, with the second reading performed by either a specialist or a general radiologist who is certified in mammography. Single reading with CAD was performed by sub-specialized mammographers.

The study compared the recall rate, sensitivity, positive predictive value (PPV), and cancer detection rate of single reading with CAD to double reading and to the first reader in the double reading program in 231,221 mammograms from 2001-2005. The study shows that single reading with CAD was as effective at finding cancers as double reading and had a lower recall rate.

Because double reading is time consuming and not generally reimbursed, CAD has become increasingly popular in the United States as an alternative way to increase sensitivity, said Matthew Gromet, JD, MD, author of the study.

According to the study, statistically significant results included a lower recall rate with CAD compared to double reading (10.6% vs. 11.9%), increased sensitivity with CAD compared to the first reader (90.4% vs. 81.4%), and increased recall rate with CAD compared with the first reader (10.6% vs. 10.2%). The sensitivity of single reading with CAD was slightly higher than double reading (90.4% vs. 88.0%), although this difference did not reach statistical significance......... Posted by: Andria      Read more         Source

February 6, 2008, 8:18 PM CT

Gene Play Role in Skin Cancer Development

Scientists at the Burnham Institute for Medical Research (Burnham Institute) have provided genetic evidence that Activating Transcription Factor 2 (ATF2) plays a suppressor role in skin cancer development. ATF2 is a protein that regulates gene transcription, which is the first step in the translation of genetic code, in response to extracellular stresses such as ultraviolet light and ionizing radiation. This function of ATF2 in stress and DNA damage response suggests that it may also play a role in the formation of tumors.

Prior studies led by Ze'ev Ronai, Ph.D. have suggested an important role of ATF2 in melanoma development and progression. In this new study, published in this week's issue of Proceedings of the National Academy of Sciences of the United States of America, the Ronai laboratory, in collaboration with Nic Jones, Ph.D. from the University of Manchester UK, used a mouse model that expresses a transcriptionally inactive form of ATF2 in skin cells (keratinocytes). When the mice were subjected to chemically mediated skin carcinogenesis, tumors appeared faster and more frequently. These findings reveal that loss of ATF2 transcriptional activity in skin exposed to carcinogens enhances skin tumor formation, suggesting a tumor suppressor role for ATF2 in keratinocytes......... Posted by: Andria      Read more         Source

January 14, 2008, 5:21 PM CT

Fruit flies all aglow light the way to cancer prevention

A green glow from a fruit fly is giving scientists the green light when they are on the right path in their quest to develop compounds that help prevent cancer.

The glow, the result of some tinkering in Drosophila, the workhorse of the genetics world, lets scientists know when powerful cancer-prevention signals similar to those spurred by protective chemicals in broccoli, cabbage, and other foods, have been turned on in the organism.

The chemical signaling system is one of the major ways that the body defends itself against toxic assaults and threats like cigarette smoke, diesel exhaust, and dangerous microbes. A gene known as KEAP1 senses danger and then unleashes NRF2, which triggers rampant anti-oxidant activity in a cell.

Now researchers from the University of Rochester Medical Center have discovered that the pathway, long recognized in people and other animals, is active in fruit flies, too, opening the door to faster, less expensive ways to find compounds that spur our natural anti-oxidant activity. The work, funded by the National Cancer Institute, is published in the Jan. 15 issue of Developmental Cell.

This is one of the main mechanisms the body uses to fight off the things that give you cancer, said Dirk Bohmann, Ph.D., professor in the Department of Biomedical Genetics and a geneticist who studies fruit flies in an effort ultimately aimed at improving human health......... Posted by: Andria      Read more         Source

December 28, 2007, 8:04 AM CT

Cancer Is Too Complex For Easy Answers

Scientists who study cancer may be prone to drawing simplistic conclusions from the powerful molecular tools now available because they don't appreciate how complex the data is that is being generated, said a team of Georgetown University Medical Center (GUMC) researchers in the recent issue of Nature Reviews Cancer.

In a review article summing up the state of the field, they said cancer scientists should endeavor to better understand the issues these genomic and proteomic technologies create or conclusions from their research may be misleading.

"These tools have allowed us to see that nature is more complex than we thought, and while we don't yet know what the overarching biological rules are - such as the interrelationship between multiple signaling pathways that can lead to cancer development - we are trying to play the game like we do," said the review's lead author, Robert Clarke, Ph.D., D.Sc., professor of oncology and physiology & biophysics at the Lombardi Comprehensive Cancer Center at GUMC, where he co-directs the Breast Cancer Program. Clarke is the interim director of GUMC's Biomedical Graduate Research Organization, which is home to more than 60 percent of the University's biomedical research funding.

"The answers to our questions are probably there in the data," he said, "but the issue is whether we can get them using these complex tools and, also, how we will know they are right when we see them"......... Posted by: Andria      Read more         Source

December 20, 2007, 9:38 PM CT

Enzyme Target for Cancer Drugs

The veil has finally been lifted on an enzyme that is critical to the process of DNA transcription and replication, and is a prime target of antibacterial and anticancer drugs. Scientists with the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) at Berkeley have produced the first three-dimensional structural images of a DNA-bound Type II topoisomerase (topo II) that is responsible for untangling coiled strands of the chromosome during cell division.

Preventing topo II from disentangling a cell's DNA is fatal to the cell, which is why drugs that target topo II serve as agents against bacterial infections and some forms of cancer. This first ever structural image of topo II should help in the development of future antibacterial and anticancer drugs that are even more effective and carry fewer potential side effects.

"Topo II has been called nature's magician because it literally can move one DNA segment through another," said James Berger, a biochemist and structural biologist who led this research. "The enzyme cleaves a double-stranded DNA, passes a second duplex through the break, and then immediately repairs the broken strands. This enables topo II to control the topology of DNA for chromosome segregation and disentanglement"......... Posted by: Andria      Read more         Source

December 13, 2007, 10:01 PM CT

Drug study for brain cancer shows promise

A clinical study conducted at Henry Ford Hospital on the use of a drug to extend the survival of patients with the most common and aggressive type of brain cancer, has yielded results that were significantly better than expected.

The randomized Phase II study focused on patients with glioblastoma multiforme (GBM), whose cancer had recurred after first- or second-line treatment. The study revealed that more than a third who were treated with Avastin (bevacizumab) alone, as well as more than half of those treated with Avastin in combination with the chemotherapy drug irinotecan, lived without further progression of the disease for a period of six months. In addition, no new or unexpected adverse effects from the use of Avastin were observed during the study.

This is very encouraging news, says Tom Mikkelsen, M.D., a neuro-oncologist who is the studys principal investigator at Henry Ford and co-director of the Hermelin Brain Tumor Center. "Historical estimates suggest that only 15 percent of patients with this aggressive type of brain cancer live without their cancer progressing within six months. Eventhough gliomas [fast-growing cancerous brain tumors] are nearly always incurable, use of a drug like Avastin may help to buy precious time for patients, as well as to preserve their physical and mental functions longer than was previously possible......... Posted by: Andria      Read more         Source

December 11, 2007, 10:23 PM CT

Cancer cell line resistant to new cancer therapy

They found the HDAC inhibitor-resistant cell line resistant to a number of therapies, including more standard therapy such as chemotherapy, but highly sensitive to heat shock protein 90, or hsp90, inhibitors, another emerging cancer therapy.

"As part of their resistance mechanisms, they acquired greater sensitivity to hsp90 inhibitors," says Dr. Bhalla, Cecil F. Whitaker Jr., M.D./Georgia Research Alliance Eminent Scholar in Cancer. "This creates a potential combination that can be tested in mouse models and ultimately clinical trials".

HDAC and hsp90 inhibitors are both being studied in combination with other cancer therapies but not each other. However the MCG researchers, who already have published work indicating a synergistic effect, were not surprised by what they found.

"Resistance to HDAC inhibitors is going to emerge, so you need a cellular model to understand mechanisms of resistance and an in vivo model, a mouse model typically, to test new combinations you design based on studies in culture," says Dr. Bhalla.

The scientists have put the cell line into a mouse model and other researchers already are asking for the resistant cell line, he says.

"This particular cell line can be used to really look at newer agents and new combinations in vitro and in vivo and see if they are safe and effective together," Dr. Fiskus says......... Posted by: Andria      Read more         Source