Thema: News: Diffusion MRI provides fast assessment of brain cancer therapy
News: Diffusion MRI provides fast assessment of brain cancer therapy
Melanie[a]
05.12.2005 18:52:31
Diffusion MRI Provides Fast Assessment of Brain Cancer Therapy
By Jeff Minerd, MedPage Today Staff Writer
Reviewed by Zalman S. Agus, MD; Emeritus Professor at the University of Pennsylvania School of Medicine.
November 01, 2005
Advise patients that while diffusion MRI appears promising for assessing brain cancer therapy, this technology is not yet routinely available and larger studies are necessary before it´s true clinical utility can be determined.
Review:
An experimental form of MRI may be able to spot quickly whether patients with brain cancer are responding to chemotherapy or radiation.
Using diffusion MRI, investigators here were able to see within three weeks whether 24 of 34 late-stage, diffuse high grade gliomas were responding. Diffusion MRI correctly identified 13 of 14 stable or responsive tumors (93%) and 11 of 15 progressive tumors (73%).
The MRI follow-up of the tumor response was performed at 10.0±0.2 weeks from the start of treatment and was available for 29 of 34 patients. It was used to identify patients as stable or responsive and progressive.
Response to treatment is typically evaluated six weeks after completion of therapy, which runs six or seven weeks. An earlier accurate evaluation could spare patients weeks of chemotherapy that is not working and allow a new treatment to be tried more quickly, reported Brian D. Ross, Ph.D., and colleagues at the University of Michigan in a study published online by the Proceedings of the National Academy of Sciences.
Diffusion MRI maps the movement of water molecules through tissue at the cellular level. Because water becomes more mobile after cellular death, the diffusion map of a tumor will change as the tumor shrinks and dies in response to therapy, the investigators said.
In the study, the 34 glioma patients underwent diffusion MRI before beginning treatment involving either chemotherapy, radiation therapy, or a combination of both. Three weeks later, patients had another diffusion MRI. Eight to ten weeks after that, the participants underwent standard MRI to determine whether their tumor responded to the therapy.
Using a cutoff value of 6.57% or less of the tumor undergoing a significant change in the diffusion of water as the threshold to indicate which tumors were not responding to therapy, diffusion MRI was found to have a sensitivity of 75% (95% confidence interval=45%-92%) and a specificity of 93% (95% CI=66%-99%).
In addition, identification of non-responsive tumors by diffusion MRI strongly correlated with time to disease progression (4.3 months versus 7.3 months in stable or responsive tumors; P<0.04) and overall survival time (eight months versus 18.2 months for patients with stable or responsive tumors P<0.01).
"When the median survival for this type of cancer is less than 52 weeks, waiting an extra 10 weeks to know if treatment is working is a significant amount of time. We hope that functional diffusion mapping will eventually allow oncologists to manage each patient´s treatment based on real-time evaluation of cellular response to therapy," said co-author Suresh Mukherji, M.D., also of the University of Michigan.
Although diffusion MRI is not yet routinely available for clinical use, the study authors believe the test may be useful for other types of cancer, including breast, head and neck, rectal, prostate and liver.
Primary source: Proceedings of the National Academy of Sciences
Source reference: Hamstra DA et al. Evaluation of the functional diffusion map as an early biomarker of time-to-progression and overall survival in high-grade glioma. Proceedings of the National Academy of Sciences. Advanced online publication October 31, 2005.
By Jeff Minerd, MedPage Today Staff Writer
Reviewed by Zalman S. Agus, MD; Emeritus Professor at the University of Pennsylvania School of Medicine.
November 01, 2005
Advise patients that while diffusion MRI appears promising for assessing brain cancer therapy, this technology is not yet routinely available and larger studies are necessary before it´s true clinical utility can be determined.
Review:
An experimental form of MRI may be able to spot quickly whether patients with brain cancer are responding to chemotherapy or radiation.
Using diffusion MRI, investigators here were able to see within three weeks whether 24 of 34 late-stage, diffuse high grade gliomas were responding. Diffusion MRI correctly identified 13 of 14 stable or responsive tumors (93%) and 11 of 15 progressive tumors (73%).
The MRI follow-up of the tumor response was performed at 10.0±0.2 weeks from the start of treatment and was available for 29 of 34 patients. It was used to identify patients as stable or responsive and progressive.
Response to treatment is typically evaluated six weeks after completion of therapy, which runs six or seven weeks. An earlier accurate evaluation could spare patients weeks of chemotherapy that is not working and allow a new treatment to be tried more quickly, reported Brian D. Ross, Ph.D., and colleagues at the University of Michigan in a study published online by the Proceedings of the National Academy of Sciences.
Diffusion MRI maps the movement of water molecules through tissue at the cellular level. Because water becomes more mobile after cellular death, the diffusion map of a tumor will change as the tumor shrinks and dies in response to therapy, the investigators said.
In the study, the 34 glioma patients underwent diffusion MRI before beginning treatment involving either chemotherapy, radiation therapy, or a combination of both. Three weeks later, patients had another diffusion MRI. Eight to ten weeks after that, the participants underwent standard MRI to determine whether their tumor responded to the therapy.
Using a cutoff value of 6.57% or less of the tumor undergoing a significant change in the diffusion of water as the threshold to indicate which tumors were not responding to therapy, diffusion MRI was found to have a sensitivity of 75% (95% confidence interval=45%-92%) and a specificity of 93% (95% CI=66%-99%).
In addition, identification of non-responsive tumors by diffusion MRI strongly correlated with time to disease progression (4.3 months versus 7.3 months in stable or responsive tumors; P<0.04) and overall survival time (eight months versus 18.2 months for patients with stable or responsive tumors P<0.01).
"When the median survival for this type of cancer is less than 52 weeks, waiting an extra 10 weeks to know if treatment is working is a significant amount of time. We hope that functional diffusion mapping will eventually allow oncologists to manage each patient´s treatment based on real-time evaluation of cellular response to therapy," said co-author Suresh Mukherji, M.D., also of the University of Michigan.
Although diffusion MRI is not yet routinely available for clinical use, the study authors believe the test may be useful for other types of cancer, including breast, head and neck, rectal, prostate and liver.
Primary source: Proceedings of the National Academy of Sciences
Source reference: Hamstra DA et al. Evaluation of the functional diffusion map as an early biomarker of time-to-progression and overall survival in high-grade glioma. Proceedings of the National Academy of Sciences. Advanced online publication October 31, 2005.
Melanie[a]
