Physician Inquiry - Information for Radiation Oncologists

A diagnosis of brain metastases regardless of the primary site of disease is a devastating event. This diagnosis is not only incurable but typically confers a short survival and a poor quality of life. Treatment has historically been whole brain radiotherapy (WBRT) or craniotomy (for resectable solitary metastases) followed by WBRT. Recent data evaluating addition of stereotactic radiosurgery (SRS) to WBRT demonstrated significant improvement for patients with brain metastases.

Several studies have demonstrated benefits in survival (median and 1yr) for patients with single and multiple mets ^1-4. Additionally, response rates, local control, symptoms and steroid requirement improved with the addition of SRS to WBRT. These improvements in quality of life are notably accomplished with little or no increase in toxicity.

The most influential trial was a large, multi-center phase III study (RTOG 95-08) that randomized patients to WBRT with or without SRS ¹. The combined treatment (WBRT + SRS) demonstrated significant improvements in survival, local control, performance status and steroid requirements. There was a 33% improvement in survival from 4.9 months to 6.5 months in patients with a single metastasis. ASTRO recently published a review of the available literature on the use of SRS in adult patients with brain metastases ². They concluded that radiosurgery boost with WBRT significantly improves local brain control rates compared with WBRT alone. This was demonstrated in all randomized trials reviewed. The degree of one-year local control improvement varied from 43% to 92%.

Citing the results of RTOG 95-08, the Radiation Therapy Oncology Group has announced a new standard of care for patients with one to three unresected brain mets ⁵ (Press Release May 20, 2004 "New Less-Invasive Treatment Dramatically Increases Survival Rates and Improves Quality of Life for Patients with Brain Metastases"). 

SRS is delivered using the Gamma Knife or a linear accelerator based stereotactic system. The Gamma Knife is accurate to less than 0.3 mm and is fully dedicated to intracranial SRS. Gamma Knife treatments are now available in the Inland Northwest through the Gamma Knife facility in Spokane. Advancements in technology and collaborative efforts have made this treatment more widely available and bring together the involvement of the patient's local physicians as part of the gamma knife team in Spokane. For details about this possibility please contact your local Radiation Oncologist or Gamma Knife of Spokane.

How does Gamma Knife treat metastatic brain tumors?

The gamma knife is a radiation delivery tool that is dedicated exclusively for the treatment of skull-based tumors and malformations.
As such, it is very accurate - with sub-millimeter precision (<.3mm)- less than half the width of a human hair. So healthy tissue is spared while a cancer-destroying dose is delivered to the tumor.

What makes a gamma knife so accurate and effective? The head is fixed in a frame that keeps the brain stable and unmoving. This head frame resembles that of a 'halo' apparatus used in neck injury patients. It goes on without much discomfort while the patient feels some pressure sensation once it is affixed.

The other factor that aids in accuracy is the fixed isocenter of radiation - 201 sources of Cobalt -60 radiation that focus at a single point (fixed isocenter). The Gamma Knife of Spokane can reach multiple metastases, tumors found deep in the brain and tumors that are near critical structures in the brain with one single dose (thus the term 'radiosurgery' versus 'radiotherapy'). A patient can also be treated multiple times should new tumors arise over the course of treatment for systemic disease.

So you and your medical team has access to a $5 million, 45,000 pound cancer-killing machine that can, in less than a few hours, deliver a dose of radiation that can stop the growth of most tumors and even eliminate other tumors altogether. Your patient will be treated in the morning, admitted overnight, and in most cases can go home the next morning.

If you have any questions about this treatment, call our nurse coordinator, Jill Adams, at 509.473.3800.

Cited References

1. Andrews DW, et al. Whole brain radiation therapy with or without stereotactic radiosurgery boost for patients with one to three brain metastases: phase III results of the RTOG 9508 randomised trial. Lancet 363 (9422): 1665-72, 2004.

2. Mehta MP, et al. The American Society for Therapeutic Radiology and Oncology (ASTRO) evidence-based review of the role of radiosurgery for brain metastases.Int J Radiat Oncol Biol Phys. 2005 Sep 1;63(1):37-46.

3. Kondziolka D, et al. Stereotactic radiosurgery plus whole brain radiotherapy versus radiotherapy alone for patients with multiple brain metastases. Int J Radiat Oncol Biol Phys 45 (2): 427-34, 1999.

4. Kocher M, et al. Linac radiosurgery versus whole brain radiotherapy for brain metastases. A survival comparison based on the RTOG recursive partitioning analysis. Strahlenther Onkol. 2004. May;180(5):263-7.

5. Press Release: Philadelphia, PA, May 20, 2004, http://www.rtog.org/members/protocols/95-08/9508broadcast.html

6. Kondziolka D, et al. Stereotactic radiosurgery plus whole brain radiotherapy versus radiotherapy alone for patients with multiple brain metastases. Int J Radiat Oncol Biol Phys 1999 Sep 1;45(2):427-34.

Additional References

7. Gaspar L, et al. Recursive partitioning analysis (RPA) of prognostic factors in three Radiation Therapy Oncology Group (RTOG) brain metastases trials. Int J Radiat Oncol Biol Phys. 1997 Mar 1;37(4):745-51.

8. Shaw, et al. Single dose radiosurgical treatment of recurrent previously irradiated primary brain tumors and brain metastases: final report of RTOG protocol 90-05. IJROBP 2000;47:291-298.

9. Hasegawa, et al. Brain metastases treated with radiosurgery alone: an alternative to whole brain radiotherapy? Neurosurg 2003; 52 (6):1318-26.

10. Sneed PK, et al. A multi-institutional review of radiosurgery alone vs. radiosurgery with whole brain radiotherapy as the initial management of brain metastases. Int J Radiat Oncol Biol Phys. 2002 Jul 1;53(3):519-26.