University of Maryland Department of Radiation Oncology a Strong Presence at National Meeting
For immediate release: September 27, 2014
The University of Maryland Department of Radiation Oncology had a strong presence at the recent 2014 annual meeting of the American Society for Radiation Oncology (ASTRO). Twenty-six of the 28 abstracts submitted by UM researchers were accepted, and these research findings were presented before radiation oncology professionals from across the United States. This is a record number of accepted abstracts for the department, underscoring the value and quality of its research program and its role as a leader in the development of new and better radiation treatments. Research findings related to a broad range of cancers, including colorectal, prostate, brain, lung and breast, and a variety of novel radiation treatment approaches and technologies. Following are summaries of several studies that were presented:
Long-term Effects of Prostate Radiation Treatment Similar in HIV-positive and Non-HIV Patients
Results from a recently-concluded study show that HIV-infected men have similar long-term outcomes and side effects from definitive prostate radiation treatment – meaning it's strong enough to cure them -- as those patients who don't have HIV. Led by Young Kwok, MD, associate professor of radiation oncology at the UM School of Medicine, the study enrolled larger numbers of patients with longer follow-up than other studies. Results show that doctors can treat HIV-positive prostate cancer patients with the same curative radiation levels as they would their non-HIV counterparts, with confidence that they won't suffer long-term complications or increased toxicity because of their suppressed immune systems or HIV medications. The researchers did find that whole pelvis radiation was associated with a decline in the number of CD4 cells—white blood cells essential to the immune system—as compared to prostate-only radiation. This decline was not associated with any infections, and cell levels stabilized and became normal within one year. These findings reinforce current standard-of-care for these patients.
The GammaPod: Improving Cosmetic Outcomes for Breast Cancer Patients
Early-stage breast cancer has been traditionally treated either through mastectomy or breast conservation therapy, which classically employs a lumpectomy and whole breast radiation. Recent advances in radiotherapy have made possible, and increasingly popular, partial breast irradiation techniques, which target only the lumpectomy cavity and a surrounding "margin" of normal breast tissue. While women who undergo this therapy are able to keep their breast and receive less overall radiation, there has been an unexpectedly high rate of fair or poor cosmetic outcomes associated with this approach. Researchers in the University of Maryland Department of Radiation Oncology have developed and are testing a new stereotactic radiotherapy device, known as the GammaPod, that allows doctors to more precisely target the tumor or lumpectomy cavity while sparing substantially more surrounding normal tissues (i.e. uninvolved breast tissue, heart, lungs, and breast skin). J.W. Snider, MD, a resident of the department, presented findings from a dosimetric study in which doctors utilized example patients' CT scans to measure the radiation dose the device would deliver for cases of early-stage breast cancer, specifically looking at the dose to tissue surrounding the tumor. Their findings demonstrate that the radiation dose to this area, utilizing the GammaPod device technique, was significantly lower than any other available partial breast irradiation approach. In an upcoming clinical trial, doctors will treat patients using this new device and seek to prove that it reduces the side effects while maintaining the efficacy of radiotherapy in early-stage breast cancer.
Gamma Ray Detector Aids in Precision of Proton Beam Treatment
Jerimy Polf, PhD, DABR, assistant professor in the UM Department of Radiation Oncology, presented findings from a study testing a gamma ray detector, a new technology he designed to improve the precision of proton treatment delivery. Proton therapy is a form of radiation used in cancer treatment. The radiation beam is highly conformal, allowing doctors to target only the tumor and avoid surrounding healthy tissue. Proton radiation has another unique quality: when the proton beam comes in contact with an object, gamma rays are emitted from the exact location of contact. Dr. Polf's gamma ray detector will help doctors to ensure the beam hits the tumor and only the tumor. If gamma rays are emitted from tissue outside the tumor, it could mean that the patient shifted and needs to be repositioned for optimal treatment, or that the tumor has changed in size, and a new treatment plan is required. Findings presented at ASTRO were of measurements and images taken by a prototype device. Dr. Polf expects that the device will be tested in the clinic, after the Maryland Proton Treatment Center, the first of its kind planned for the Baltimore/Washington area, opens to patients in 2015.
Tumor Volume as a Prognostic Tool in Metastatic Colorectal Cancer Patients
Researchers in the University of Maryland Department of Radiation Oncology are studying various prognostic factors in patients with unresectable colorectal liver metastases who receive selective internal radiation therapy (SIRT) to the liver. SIRT delivers millions of radioactive microspheres intra-arterially into liver tumors to provide a high dose of very targeted radiation. Whereas tumors are typically measured using one or two dimensions on imaging, Michael Chuong, MD, and his team evaluated three-dimensional (volumetric) measurements of tumors in SIRT patients. At the ASTRO meeting, they presented that pre-treatment tumor volume significantly predicts for treatment response and also that post-treatment volumetric response predicts for survival outcomes.
Overall Survival of Low-grade Glioma Patients Improved Through Adjuvant Chemotherapy after Radiation
Minesh P. Mehta, MBChB, FASTRO, professor of radiation oncology at the University of Maryland School of Medicine and associate director of clinical research in the Department of Radiation Oncology, presented the most recent findings from a long-term study, known as Radiation Therapy Oncology Group (RTOG) 9802, which confirm that patients with low-grade glioma who received a combination treatment of radiation followed by chemotherapy experienced improved progression-free survival and overall survival as compared to patients who received radiation alone. The initial study results, published in 2012 with 5.9 years median patient follow-up, showed that the addition of chemotherapy to the treatment regimen delayed tumor recurrence but didn't significantly prolong overall survival as compared with patients who received only radiation. These latest trial data, presented at ASTRO, had a median follow-up of 11.9 years and showed that radiation plus chemotherapy significantly improved progression-free survival—10.4 years versus 4 years for patients who only received radiation. The long-term results also showed a statistically significant improvement in overall survival—13.3 years compared with 7.8 years for radiation alone. These findings were originally reported in June 2014.