SEATTLE, Sept. 21 For women whose breast cancer has spreadto their lymph nodes, a magnetic resonance imaging (MRI) scan could replaceexploratory surgery as the method for determining whether those women needradiation therapy to treat their disease, according to a study to be presentedduring the annual meeting of the American Society for Therapeutic Radiologyand Oncology (ASTRO) which opens today in Boston.
In a retrospective study of 167 patients who underwent radiation therapyfor invasive breast cancer after surgical staging of their tumors, physicianresearchers at the Seattle Cancer Care Alliance and University of WashingtonMedical Center found that the tumors' physiological information shown on MRIscans correlated with surgically based findings of cancer having spread tolymph nodes. This suggests that breast MRI could help determine if womenscheduled to undergo surgery will later need radiation therapy and how much.
The findings are significant because the standard of care for women withbreast cancer has evolved during the past five years. In the past, decisionsregarding radiation therapy were made after surgery and before chemotherapy,according to lead author Christopher Loiselle, M.D., a resident in theDepartment of Radiation Oncology at UW Medical Center. Today, increasingnumbers of women may be treated with chemotherapy before surgery.
"When you give chemotherapy first, and then perform the surgery to removethe cancer and sample the lymph nodes, you reduce your ability to know whetherthere was cancer in the axillary (underarm) lymph nodes before the patient wastreated with chemotherapy," Loiselle said. "This raises the question: isthere another way to stage those lymph nodes? Our study showed that tumorcharacteristics as seen on an MRI scan may be the answer."
The ultimate benefit is that some women can be spared radiation therapy,especially those with smaller tumors and tumors that have not spread to thelymph nodes, he said.
A contrast dye used routinely in MRI scans not only highlights the sizeand location of the tumor but also details the blood vessels feeding thetumor. The kinetics or activity of the contrast dye in the tumor providedsome key parameters for comparing MRI to traditional surgical tumor staging,he said.
"MRI is evolving rapidly as a diagnostic tool for breast cancer,particularly among women with high risk for the disease, because not only doesit give us traditional anatomic information about tumors but information aboutthe biology of the tumor as well," Loiselle said.
Prospective studies will need to be done to confirm the value of MRI scansin staging tumors for radiation therapy, he said.
About Seattle Cancer Care Alliance
Seattle Cancer Care Alliance, established in 1998, unites the adult andpediatric cancer-care services of Fred Hutchinson Cancer Research Center, UWMedicine and Children's Hospital and Regional Medical Center. A major focusof SCCA is to speed the transfer of new diagnostic and treatment techniquesfrom the research setting to the patient bedside while providing premier,patient-focused cancer care. Patients who come to SCCA receive the latestresearch-based cancer therapies as well as cutting-edge treatments for anumber of non-malignant diseases under development by its partnerorganizations. SCCA has three clinical-care sites: an outpatient clinic onthe Fred Hutchinson campus, a pediatric-inpatient unit at Children's and anadult-inpatient unit at UW Medical Center. For more information about SCCA,visit http://www.seattlecca.org.
Dean Forbes, 206-667-2896
SOURCE Seattle Cancer Care Alliance