Treating VHL Brain and Spinal Tumor

We have had a rise recently in inquiries about the use of Cyberknife on hemangioblastomas of the brain, spinal cord, and brainstem.  These machines are being installed at a number of hospitals around the country, which are advertising their services on billboards, radio, and television, as being miraculous for all kinds of tumors.

Cyberknife is one brand of machine that delivers doses of stereotactic radiation (SRS).  While most SRS machines are limited to tumors inside the bony skull, the Cyberknife is able to track its target tumor as it moves with each breath. In theory, it can be used on any tumor.

With any new treatment, however, there is a need to evaluate not only the feasibility, we need to evaluate the efficacy of the treatment.  Radio Frequency Ablation (RFA) is still considered experimental to some extent because the 10-year data has only now begun to emerge.  Similarly, we need 10-year data to determine whether treatment of hemangioblastoma is effective.  Sure, we can do it, but does it do the job?

Dr. Ashok Asthagiri of the U.S. National Institute for Neurological Disorders and Stroke (NINDS), one of the National Institutes of Health (NIH), presented a review of twelve papers over the past 16 years, and the results of a study of 20 people with VHL who underwent SRS treatment of 44 hemangioblastomas, with an average follow-up period of 8.5 years.  For the first time, we have a significant number of patients over a length of time that begins to show the long-term effectiveness of this treatment, compared to the standard treatment, open surgery.

Dr. Asthagiri’s talk goes through the data in detail.  If you are considering radiosurgery, we encourage you to listen to the entire presentation.  We have summarized the key points in Figure 1. While open surgery is obviously more difficult immediately, the recovery is better defined and the tumor is much better controlled over time.

Guidelines for SRS: (Lunsford et al.)

- Tumor should be smaller than 3.2 cc
- Tumor should receive 15 Gray (15 Gy) at the edges
- Tumor should not have a cyst. 

 

Guidelines for open surgery (Oldfield et al):

- Tumor should be mildly symptomatic.  Don’t wait until something doesn’t work.

From the NINDS Natural History study (19 patients with 138 tumors over 12 years) we learned:

- 58 of the 138 tumors (42%) became symptomatic
- 26 of these 58 tumors (45%) were not present on the first MRI
- 6% of tumors followed a linear growth pattern
- 94% of tumors followed a “stuttering” growth pattern (see Figure 2)
- 85% of the symptomatic tumors had an associated cyst or syrinx
- 80 of the 138 tumors (58%) never became symptomatic at all

 

Figure 2: Stuttering Growth pattern.  

134 out of 138 tumors (94%) displayed a stuttering growth pattern.

Key points to remember:

 1. If someone has 10 tumors on the scan, statistically 6 of those tumors will probably never grow.

 2. If someone has 10 tumors on the scan, and we treat 10 tumors, half the time we would miss the tumor that would eventually become a problem because it was not even present on the first scan.

 3. If we treat a small tumor with SRS and it doesn’t grow, how do we know whether it was controlled by SRS or whether it is in a quiet period of stuttering growth?  (See Figure 3)

 4. In the Natural History study, if they had treated every tumor that showed growth (rather than waiting for symptoms), each patient would have had an average of four additional surgeries over a 10-year period.  By waiting for symptoms they were able to reduce the wear-and-tear on the patient.

 5. Tumors treated with SRS (following the guidelines above) which subsequently required surgical removal showed incomplete ablation of the tumor.  Some cells in the tumor had died, others had continued to grow.

Dr. Asthagiri’s major concerns with SRS are:

- Near-term swelling (usually 3-18 months after treatment) may increase symptoms.  Be sure to review the Questions to Ask Your Doctor before the treatment, and make a plan with your doctors for how to handle swelling if it occurs.

- Long-term lack of efficacy.  There is a 50% chance that this same tumor will become a problem to you in 7 years.

- Follow-up surgery.  Having to do an operation in a place that has previously had radiation treatment can sometimes make surgery more difficult.

Figure 3: Recurrence.  One tumor studied at NIH showed no growth for six years following radiosurgery, then grew rapidly within the next six months, requiring open surgery.  Was this tumor controlled by SRS for six years? or would it have grown at all during that time even if left untreated?

 

Conclusions:

As long as the tumor is reasonably approachable, open surgery is still the first choice for long-term control.  Deeper tumors, or ones on the front side of the spinal cord, are associated with more problems in surgery.  Likewise, certain locations in the brain stem might be associated with more problems in surgery.  You need to speak with a surgeon who has significant experience with hemangioblastomas before deciding that a tumor is truly inoperable.

It is hard to overcome the desire not to have surgery, especially if you have had multiple surgeries before.  SRS is an alternative to be explored, but don’t just look at the procedure itself.  We also need to consider the long-term effects: it’s a 50:50 chance that the tumor we treat today will become a problem to you in seven years.

The best way to improve the outcome:

- Monitor all tumors at least once every 1-2 years

- If any CNS involvement is seen, assemble your team and develop a relationship with them. 

- Find the best neurosurgeon in your area, share the VHL Handbook.  If needed, send scans to one of the CCC’s or expert centers for a second opinion, and share that input with your local surgeon.

 

- Identify symptoms at early stages.  Ask the doctor what symptoms to watch for, and don’t be shy to call when symptoms occur.  Don’t quietly wait two months for the next available appointment.  Make sure the surgeon is aware of the level of symptoms, and the rate of change.  Tumors grow slowly; cysts can grow dramatically.

To see the video of Dr. Asthagiri’s presentation, his slides, and a detailed list of references, please go to http://vhl.org/videos/webinars/radiosurg1.php

For the “Questions to Ask Your Doctor” when considering stereotactic radiosurgery, please see the VHL Handbook, or http://vhl.org/stereo

Other machines used to perform SRS: Gamma Knife, Proton Beam, Linear Accelerator, Collimator, Cyclotron, Photon Beam. 

As printed in the VHL Family Forum 18:1, February 2010. For permission to reprint, please contact VHL Family Alliance, editor@vhl.org. Further information is available from the VHL Family Alliance, info@vhl.org.