Tomotherapy for Patients with Limited Metastatic Cancer
Name of the Trial
Phase II Study of Hypofractionated Highly Conformal Radiotherapy With Helical Tomotherapy in Patients With Extracranial Oligometastases (NCI-07-C-0230). See the protocol summary.
Dr. Deborah Citrin, NCI Center for Cancer Research
Why This Trial Is Important
Most people who die from cancer succumb to metastatic disease, cancer that has spread to other parts of the body. Treatment for metastatic cancer is usually undertaken to help relieve pain and other symptoms because the cancer is often considered too widespread to be cured.
Sometimes, though, metastatic cancer can be detected and treated before it becomes widespread. Moreover, certain types of cancer may spread to only one or a few other locations. Such limited metastatic tumors are called oligometastases (the Greek word "oligos" means few or little). Previous studies have shown that removing these tumors surgically can result in long-term survival for some patients, effectively curing them of their cancer.
Doctors want to find ways to extend treatment with curative intent to patients whose oligometastases cannot be surgically removed or who are unwilling to risk the complications of major surgery. One approach being investigated is the use of high-dose radiotherapy delivered over a short period of time (hypofractionated) to destroy tumors without surgery.
In this trial, patients with oligometastases outside the brain will be treated with a type of radiation therapy called helical tomotherapy. Helical tomotherapy uses a machine that is similar to a CT scanner but also contains a source for therapeutic levels of radiation. The tomotherapy machine delivers high-dose radiation from any angle, allowing the precise targeting of small or irregularly shaped tumors (that is, the radiation pattern is "highly conformal"), which minimizes the radiation exposure of surrounding normal tissue. In contrast, traditional external beam radiotherapy targets the tumor from only one or a few angles, exposing surrounding normal tissue to substantial doses of radiation and limiting the amount of radiation that can be delivered.
"The idea of this study is to look at patients with limited metastatic disease as potentially curable, even if their tumors can't be removed surgically," said Dr. Citrin. "If we can destroy the patient's tumors with another local therapy, in this case highly conformal radiotherapy, we may be able to extend survival and possibly cure some people."