|
|||||||||||||||
|
Home
|
Postcards From
L.A. — News From ASTRO Editor’s Note: These reports were compiled from press materials supplied by the American Society of Therapeutic Radiology and Oncology (ASTRO) at the society’s 49th annual meeting this fall. Standardizing Dose Volume
Reporting in Lungs “This is the first study to evaluate the degree of differences that 4D-CT has on dose volumes and to propose a method to standardize them for more effective radiation treatment,” said Mary Kara Bucci, MD, study author and assistant professor of radiation oncology at the M. D. Anderson Cancer Center in Houston. “We believe standardized reporting can lead to better interpretation of existing data and more accurate reporting of future studies. This will lead to improved risk assessment in planning individualized patient care.” Radiation oncologists use a series of CT scans that measure how much a tumor moves when a patient breathes. The series of 3D images over time is called 4D-CT. The technique allows radiation oncologists to adjust radiation treatment to account for the patient’s breathing motion. However, radiation doses are measured by the volume of a person’s lungs, and lung volumes change as the patient inhales and exhales. Because of these changes, there is a substantial difference in the reporting of the amount of normal lung tissue exposed to radiation. The study sought to improve the accuracy of dose-volume reporting and thus lower the risk of lung injury to lung cancer patients. The retrospective study involved 40 stage 3/4 non–small-cell lung cancer patients who received a 4D-CT scan and a fast free-breathing helical CT scan. It shows large differences in reported dose-volume histogram values when different lung volume definitions were used. The researchers also found population-based relationships among different lung volumes that can be used to convert these histogram values into a more standardized definition of dose volume. Preventing Lung Scarring
May Extend Lives of Lung Cancer Patients “The toxicity of pulmonary fibrosis limits the amount of the radiation dose that can be safely given to patients,” said Simon Cheng, MD, PhD, study author and a radiation oncologist at New York University Medical Center. “These study results may lead to more effective radiation therapies for advanced lung cancer, which is the leading cause of cancer deaths in the U.S.” More than 50% of patients receiving radiation therapy for advanced lung cancer develop the painful fibrosis, which can be fatal in some cases. The lung inflammation and scarring causes patients to feel short of breath, have a chronic dry cough, feel fatigue and pain in the chest, and suffer loss of appetite and weight loss. Over time, fibrosis causes the lungs’ air sacs to be replaced by scar tissue, causing breathing difficulty and an irreversible loss of the tissue’s ability to transfer oxygen into the bloodstream. This study involved mice treated with a 14-Gray single dose of radiation to the lungs. Researchers wanted to determine if using a pharmaceutical antibody to block integrin beta6 could prevent the onset of radiation-induced pulmonary fibrosis. The study shows that mice given integrin beta6 monoclonal antibodies did not develop radiation-induced lung fibrosis, while the control group of mice did. “Fibrosis is a very serious side effect that often keeps doctors from giving patients a full dose of radiation for fear that the serious problems caused by fibrosis will outweigh the good done by the radiation. If further studies conclude that this drug can indeed prevent fibrosis in lung cancer patients, I believe researchers are a huge step closer to curing this disease,” said Cheng. Radiation Boost Dose Reduces
Breast Cancer Recurrence Although younger women benefited most from an extra dose of radiation, the findings show that women of all ages who had a boost dose of radiation after standard treatment were more likely to be cancer-free over a 10-year period. The study involved 5,318 women who underwent lumpectomies and whole breast radiation treatment as part of their breast-conserving therapy for stage 1 and 2 cancer and were evaluated 10 years later. Researchers wanted to determine if a boost dose of radiation following this treatment would decrease the risk of breast cancer recurrence. In addition, a subgroup of 1,725 patients was evaluated to find the highest risk factors for localized breast cancer recurrence. “The study found that the largest benefits of the boost dose of radiation after standard breast-conserving treatment is seen in young women, who have a higher risk of breast cancer recurrence to begin with,” said Harry Bartelink, MD, PhD, senior author of the study and the chair of radiotherapy and a radiation oncologist at The Netherlands Cancer Institute at Antoni van Leeuwenhoek Hospital. For patients with early-stage breast cancer, the current standard treatment involves breast-conserving surgery (lumpectomy) followed by radiation therapy to the breast over a six- to eight-week period to kill any remaining cancer cells. In this study, an additional boost of high-dose radiation was given after conventional radiation therapy to the lumpectomy site where the tumor was removed to potentially increase the chances of a cure. With a lumpectomy, the surgeon removes the tumor, along with nearby healthy tissue. If the outside of the tumor, or margin, has cancer cells present, it’s considered a positive margin. If it’s unclear or a very small distance, doctors call it a close margin. Women who have positive and close surgical margins are at a higher risk of their breast cancer returning compared with those who have negative margins. The study also found that younger early-stage breast cancer patients are most likely to have their cancer return—particularly those who have positive surgical margins—because their cancer tends to be more aggressive. Radiation Plus Chemo Quadruples
Survival Time for Patients With Fatal Brain Cancer Before the chemotherapy treatment, GBM patients typically only lived between six and 12 months after diagnosis, and there were nearly no survivors beyond two years. This type of cancer accounts for 20% to 25% of all primary brain tumors. “A substantial number of patients with glioblastoma now have a good chance of surviving at least a few years and of enjoying a productive life during this time, which was almost unthinkable less than a decade ago,” said René-Olivier Mirimanoff, MD, the study’s lead author and a radiation oncologist at the Centre Hospitalier Universitaire Vaudois in Lausanne, Switzerland. Early results of the phase 3 trial published in The New England Journal of Medicine in 2005 showed for the first time that twice as many GBM patients treated with TMZ and radiation therapy survived two years after diagnosis compared with those who received radiation alone. The trial involved 573 patients who were randomized to receive TMZ during and after radiation therapy or radiation alone. This treatment immediately became the standard treatment for GBM patients worldwide. Researchers extended the study to determine if patients with GBM who had this treatment plan could live more than two years. Updated results show that 12% of patients who added TMZ during and after radiation treatment lived for four years compared with 3% of those who received radiation alone. Findings also show that the main group of patients who survived for four years after diagnosis was less than the age of 50 and in otherwise good health without any prior major medical condition. More than one quarter (28%) of these patients treated with TMZ and radiation lived for four years vs. only 7% of patients who received only radiation therapy. “Since GBM patients can now live longer, oncologists are monitoring them more closely and a substantial proportion of these patients are being actively treated when their cancer returns through a combination of treatment options,” said Mirimanoff. “This new management approach was extremely unlikely 10 years ago.” Breast Cancer Recurrence
More Common in Black Women The study, reported at ASTRO’s 49th annual meeting, also shows that younger African American early-stage breast cancer patients have a higher disease stage at diagnosis and more aggressive tumors than Caucasian women who undergo similar treatment. “This study confirms the aggressive nature of breast cancer in African American women and emphasizes how important it is for all African American women to see their healthcare providers regularly and to go for screening mammograms to try to catch any abnormalities early,” said Meena S. Moran, MD, the study’s lead author and a therapeutic radiologist at Yale University School of Medicine in New Haven, Conn. “This study also points out the need for further research in evaluating the underlying molecular, genetic, and biological differences in breast cancers in African American women so that we can develop better strategies for helping these women beat their cancer.” The cohort study involved 2,382 patients over a 30-year
period who underwent a lumpectomy and radiation therapy for early-stage
breast cancer. Researchers wanted to find out if there were differences
in the outcomes between African American and Caucasian patients. Findings
showed that 10 years after treatment with lumpectomy and radiation,
17% of African American women had their breast cancer recur compared
with 13% of Caucasian patients.
|
|
3801 Schuylkill Rd • Spring City, PA 19475 Publishers of Radiology Today All rights reserved. |