Appendix 2.
Questionnaire Responses
Question 1. Are you a physician?Total Responses: 297
No. If you are not, thank you very much for your time and participation. / 10.4%
Yes. If yes, please proceed to the next page (page button is at the top right-hand side). / 89.6%
Question 2. In which region of the country do you practice?
Total Responses: 160
Northeast / 24%
Southeast / 16%
Midwest / 33%
Northwest / 8%
Southwest / 19%
Question 3. In which field do you practice?
Total Responses: 172
Neurosurgery / 20%
Neuro-Oncology / 26%
Radiation Oncology, CNS as a minor component of practice / 38%
Radiation Oncology, CNS as a major component of practice / 15%
Neuro-Radiology / 1%
Question 4. In which setting do you practice?
Total Responses: 173
Academic – University / 62%
Academic – Non-University / 9%
Hospital-Based Practice / 20%
Group Practice / 6%
Individual Practice / 3%
Question 5. Does your facility perform intracranial stereotactic radiosurgery (SRS)?
Total Responses: 170
Yes / 94%
No / 6%
Question 6. How many practitioners perform intracranial SRS at your institution?
Total Responses: 165
1 / 10%
2 / 21%
3 / 21%
4 / 16%
>4 / 33%
Question 7. What intracranial SRS system do you use?
Total Responses: 166
Gamma Knife ® System (Perfexion or Non-Perfexion) / 37%
LINAC-based system (CyberKnife®, Tomotherapy®, and other systems) / 66%
Both LINAC and Gamma Knife® / 3%
Question 8. How many cases of intracranial SRS does your institution perform per year?
Total Responses: 159
<50 / 20%
50-100 / 28%
101-200 / 25%
201-400 / 16%
>400 / 12%
Question 9. What percent of lesions treated with intracranial SRS result in CLINICAL (e.g. symptomatic) radiation necrosis?
Total Responses: 157
<1% / 15%
1-5% / 61%
6-10% / 20%
11-15% / 2%
16-20% / 2%
>20% / 1%
Question 10. What percent of lesions treated with intracranial SRS result in ASYMPTOMATIC (e.g. radiographic) radiation necrosis?
Total Responses: 159
<1% / 5%
1-5% / 23%
6-10% / 33%
11-15% / 19%
16-20% / 10%
>20% / 11%
Question 11. What would be your preferred modality for the diagnosis of radiation necrosis?
Total Responses: 106
Clinical Diagnosis / 37%
Magnetic resonance imaging (MRI) / 19%
MRI with relative cerebral blood volume / 14%
Magnetic resonance spectroscopy / 16%
Positron Emission Tomography (PET) with radiolabeled 18-fluoro-deoxyglucose (FDG-PET) / 8%
PET with other radiotracer (specify) / 2%
Single photon emission computed tomography (SPECT) / 5%
Question 12. Which imaging modality/modalities do you use in your practice to diagnose radiation necrosis? (check all that apply)
Total Responses: 576 modalities selectedRespondents Using Modality
Clinical Diagnosis / 126
Magnetic resonance imaging (MRI) / 146
MRI with relative cerebral blood volume / 86
Magnetic resonance spectroscopy / 100
Positron Emission Tomography (PET) with radiolabeled 18-fluoro-deoxyglucose (FDG-PET) / 97
PET with other radiotracer (specify) / 13
Single photon emission computed tomography (SPECT) / 13
Question 13. Which imaging modality/modalities do you use in your practice to diagnose radiation necrosis? (check all that apply)
Total Responses: 208
Every 4-6 weeks with imaging / 14%
Every 4-6 weeks without imaging / 8%
Every 6-10 weeks with imaging / 22%
Every 6-10 weeks without imaging / 5%
Every 3 months with imaging / 47%
Every 3 months without imaging / 4%
Question 14. After what period of time do you consider patients with a diagnosis of radiation necrosis treated with steroids without resolution of symptoms to have steroid-refractory radiation necrosis?
Total Responses: 166
0-2 weeks / 5%
2-4 weeks / 18%
4-6 weeks / 35%
6-8 weeks / 19%
> 8 weeks / 22%
Question 15. How do you treat steroid-refractory intracranial radiation necrosis? First Choice
Total Responses: 138
Resection / 63%
Bevacizumab (Avastin ®) / 25%
Pentoxifylline (Trental ®) / 9%
Hyperbaric Oxygen Therapy (HBOT) / 3%
Other / 1%
Question 16. Clinical/radiographic impression of a 65-year-old gentleman with renal cell carcinoma metastatic to brain, status-post SRS to the left frontal lobe with an asymptomatic enlarging mass at the site of prior SRS noted on 6-month routine follow-up.
Total Responses: 168
Radiation necrosis / 38%
Recurrent Tumor / 7%
Combined radiation necrosis and recurrent tumor / 34%
Neither radiation necrosis nor recurrent tumor / 4%
Unable to Discern / 16%
Other / 1%
Question 17. Regarding the patient and scenario in Question 16, what is your next step?
Total Responses: 167
Short-term follow-up with repeat MRI / 58%
Start steroids / 26%
Consider biopsy/resection / 7%
Bevacizumab (Avastin ®) / 1%
Pentoxifylline (Trental ®) / 1%
Start Hyperbaric Oxygen Therapy (HBOT) / 1%
Other / 6%
Question 18. Mr. Doe returns to your office two months later with increasing symptoms of difficulty moving his right hand and arm to the point that is not able to dress himself. What is your next step (based on your initial step in the previous question)?
Total Responses: 165
Short-term follow-up with repeat MRI / 4%
Start steroids / 57%
Consider biopsy/resection / 28%
Bevacizumab (Avastin ®) / 5%
Pentoxifylline (Trental ®) / 0%
Start hyperbaric oxygen therapy (HBOT) / 2%
Other / 5%
Question 19. Ms. Smith is a 59-year old woman with a melanoma metastatic to brain, status-post SRS. She was asymptomatic after the treatment, but, at her 4-month follow-up you note that she has findings and symptoms consistent with radiation necrosis. What is your next step?
Total Responses: 165
Short-term follow-up with repeat MRI / 9%
Start Steroids / 81%
Consider biopsy/resection / 5%
Start bevacizumab (Avastin ®) / 2%
Start Pentoxifylline (Trental ®) / 2%
Start hyperbaric oxygen therapy (HBOT) / 0%
Other / 2%
Question 20. Ms. Smith is seen one month later with no improvement in her symptoms. What is your next step (based on your answer to Question 19)?
Total Responses: 167
Short-term follow-up with repeat MRI / 8%
Start Steroids / 11%
Consider biopsy/resection / 47%
Start bevacizumab (Avastin ®) / 22%
Start Pentoxifylline (Trental ®) / 4%
Start Hyperbaric Oxygen Therapy (HBOT) / 4%
Other / 4%