Radiation Treatments

Last Updated: 02/27/17

(Radiation Therapy & Radiosurgery)

Index

  1. Understanding Radiation
    1. Basic Facts
      1. Ionizing Radiation
      2. Non-ionizing Radiation
    2. Delivery Methods
      1. SRS (Stereotactic Radiosurgery)
      2. FSR (Fractionated Stereotactic
        Radiotherapy)
      3. Conventional Radiotherapy
    3. Machine Sources
      1. CyberKnife
      2. Proton Therapy - LINAC
      3. Gamma Knife

  2. Radiation Issues
    1. Radiation Effectiveness
    2. More Tumors and Cancer
    3. Radiation Induced Necrosis (RIN)
    4. Cognitive Thinking
      - Brain Necrosis
      / Neurologic Loss
    5. Nerve Damage
    6. Hearing Implant Damage
    7. Hair Loss

  3. Advantages and Reasons Radiation
    might be Suggested
    1. Potentially Delaying Nerve Damage
    2. Inoperable Location
    3. Poor Health / Elderly
    4. Fast Recovery
    5. Patient Refusal of Surgery

  4. Questions to Ask Your Doctor
  5. Sources
schwannoma, typical, lobular

The primary treatment for NF2 tumor management is surgical removal for good reasons. The primary issue is due to the tumor suppressor gene MERLIN; people with NF2 are at a higher risk of many of the issues that can happen from radiation therapies. The other issue is NF2 tumor formation is not always as simple as it appears to be in MRI scan.

It is important to understand the pros, cons and have questions surrounding these treatments if considering radiation therapy with a doctor. While radiation treatment may be a good choice to take care of an immediate tumor problem, it can result in problems weeks, months or even years later.(Cancer Connect, 2014)

Topics here include:

  1. Understanding Radiation
  2. Understand where radiation comes from and how it can be used in different surgical and radiotherapy forms.

  3. Radiation Issues
  4. While some radiation side effects are more common for people with NF2, radiation is used for many other conditions. It is helpful to know general issues as well as the NF2 specific ones.

  5. Advantages and Reasons Radiation might be Suggested
  6. here is a list of factors that should be discussed with your doctors before having radiation treatment. You should feel comfortable enough with the medical team you plan to allow treating you to, asking and making sure they understand your concerns and answer your questions.

  7. Questions to Ask Your Doctor
  8. There are specific reasons a form of radiation might make an individual a candidate for a radiation treatment for a specific damaging tumor.


1. Understanding Radiation

1. 1. Basic Facts

All people are exposed to radiation constantly in our daily lives, this is unavoidable. Radiation is energy that radiates from a source and travels through space may leave part of its energy in something (matter) it meets. It is capable of stripping electrons from atoms thereby breaking chemical bonds. This is particularly dangerous if the matter it encounters is DNA. It can damage cells and tissues. However, only Ionizing Radiation is dangerous and can affect the development or growth of tumors. Non-ionizing Radiation energy is too low to be of much concern. (AFRRI Staff, 2014)

1.1.1. Ionizing Radiation

  • Natural Sources: Ultraviolet radiation from the sun and cosmic energy, uranium, ores, and radon.(Appleby, 1996)
  • Medical Scans: CAT Scans also known as CT Scans and X-Rays including mammograms and dental x-rays.(Claus, 2012)
  • Medical Treatments: Cyber Knife, Gamma Knife and Proton Beam Radiation Treatments (Amichetti, 2012)
  • Ionizing radiation can cause damage to matter, particularly living tissue. For example, DNA is vulnerable to this type of radiation and could cause mutations if exposed to enough of it over a long enough period of time. At high levels it is therefore dangerous, so it is necessary to control our exposure.(World Nuclear News)

1.1.2. Non-ionizing Radiation

Sources of the fairly non-damaging non-ionizing radiation include magnetic fields, ultrasound, visible light, infrared, radio waves, microwaves, power lines and lasers. There is still debate among scientists about how non-damaging non-ionizing radiation really is. (Ronca, 2014)

1.2. Delivery Methods

Different radiation treatment options for the treatment of inoperable and recurrent benign NF2 tumors are available. (Johnson, 2008),(NIDCD, 2010)

During these treatments, the head is secured in a machine and the radiation is focused on the tumor. The duration of treatment and doses used depend on the tumor size, the specific machine and radiation treatment being used. (NIH, 2010)

There are several delivery methods of which you should be aware. You should talk to your doctors about the pros and cons of each of them:

1.2.1. SRS (Stereotactic Radiosurgery)

  • The highest amount of radiation possible is given in one high dose treatment session.
  • SRS is preplanned prior to the treatment which results in accurate target positioning of radiation to the tumor. The tumor is mapped.
  • The aim of SRS is to destroy target tissue while preserving adjacent normal tissue.(Amichetti, 2012)

1.2.2. FSR (Fractionated Stereotactic Radiotherapy)

  • A lower dose of radiation is given than in SRS. The radiation is given in multiple treatment sessions.
  • FSR is preplanned prior to the initial treatment resulting in accurate target positioning of the radiation to the tumor. The tumor is mapped.
  • FSR relies on the different sensitivity of the target and the surrounding normal tissue to the total accumulated radiation dose.( Amichetti, 2012)

1.2.3. Conventional Radiotherapy

  • Conventional Radiotherapy is radiation given in multiple treatment sessions.
  • Consists of a general scan just prior to treatment and radiation aimed at the center of the tumor mass.
  • Typically, conventional radiotherapy damages some amount of the surrounding tissues to guarantee all tumor cells are destroyed.(Amichetti, 2012)

1.3. Machine Sources

  • CyberKnife - Radiosurgery
  • Proton Therapy - LINAC
  • Gamma Knife - Radiation Therapy


2. Radiation Issues

Some of the concerns of radiation therapy are related to changes in the tumor.

2.1. Radiation Effectiveness

The success or failure of a treatment is unknown until changes can be detected. Treatment is deemed a success if the tumor stops growing or shrinks and a failure if it continues to grow. These changes can take up to six months to see on an MRI. In addition radiation can result in initial tumor swelling before shrinking or stabilizing. Even if a tumor might eventually shrink after treatment, there could be potential harmful consequences of swelling depending on tumor shape and location.

There can be further complications even when tumors to shrink, the shrinkage may only last for a period of years and if the tumor begins to grow, but radiated tumors have a chance of require follow up treatment. Radiation treatments change the consistency of the tumor mass making subsequent surgery more complicated. It may also result in more extensive nerve damage if surgical removal is required.


2.2. More Tumors and Cancer

As a result of the missing or mutated tumor suppressor gene, radiation therapies can place people with NF2, at a higher risk for growth of additional tumors, increased growth of existing tumors in the surrounding area of treatment and put these patients at a higher risk of the tumor becoming malignant. While the chance of a tumor becoming malignant is small it is a risk nonetheless. The risk of Cancer is higher for NF2 patients than non-NF2 patients. [(Wiemels, 2010), (Evans, 2009)]

2.3. Cognitive Thinking / Neurologic Loss: Radiation Induced Necrosis (RIN)

Neurological impairments can develop, based on the area of brain that was treated with radiation and possibly lead to seizures among other problems.( Department of Nursing, 2011), ( Hladik, 2016)

Cognitive Issues:

  • Attention
  • Auditory Processing
  • Working Memory
  • Logic and Reasoning
  • Long-Term Memory
  • Processing Speed
  • Visual Processing
  • Impaired Mental Status - alertness complications, amnesia, confusion, and disorientation.
  • Intellectual Impairment - This is mental retardation due to brain cell death in the area of the brain that was treated.

RIN is necrosis (cell death) and edema (cell swelling) in the tissues that surround the area of treatment. While not a tumor, RIN can act like a tumor having mass effects (crowding of other tissues) and may have to be removed by surgical means. This complication is thought to occur in between 1 and 15% of treatments.(Kim, 2007)
Brain cell death can cause Seizures.

Highest Risk of Cognitive Issues: Children and Young Adults

At birth and throughout adolescence, the human brain is in a developmental stage. Radiation therapies done before the brain is finished developing leaves people at a higher risk of long term cognitive issues.

2.4. Nerve Damage

Radiation can sometimes destroy the nerve the treatment was aiming to save. It can also destroy or damage other nerves as well. For example sometimes the Facial Nerve is damaged during VS (Vestibular Schwannoma) radiation treatments, but it can also damage the actual Vestibular Nerve the tumor is growing on. The possible risk of damage to not just the treated nerve but to the surrounding nerves is a reason that certain areas of the brain cannot be treated with radiation.(Plotkin, 2008)

2.5. Hearing Implant Damage

A patient with an ABI or CI may have their implant permanently damaged by radiation if it is administered near the device. The implant should be a specific distance away. The exact distance varies based on radiation doses, but would typically be safe from radiation treatments on the other side of the brain than the implant.

2.6. Hair Loss

This might happen only in the area of treatment and may not be permanent. How much hair is lost varies.(Department of Nursing, 2011)


3. Advantages and Reasons Radiation might be Suggested

There are specific reasons a form of radiation might make an individual a candidate for a radiation treatment for a specific damaging tumor.

3.1. Potentially Delaying Nerve Damage

Radiation may be more likely to save a nerve or the remaining nerve function that a Schwannoma tumor is growing on, for an extended period if the treatment is successful.(Lustgarten, 2013)

3.2. Inoperable Location

Radiation is worth considering if a tumor is in an inoperable location (too far in the brain to reach), this would not include tumors close to the brainstem.(Delannes, 2012)

The procedure is non-invasive.(Lustgarten, 2013)

3.3. Poor Health / Elderly

Radiation might be a better treatment if a patient is not healthy enough to cope with traditional microsurgery. It might be the only choice in the case where surgery would be life threatening, elderly patients, very low body weight patients or patients in general poor health. These patients would not pass pre-surgical screening. (Husseini, 2013)

3.4. Fast Recovery

Recovery from Radiation treatment is short and is often done as an Outpatient procedure. Patients are often released to go home the same day as the procedure.(UT Dept of Neurology, 2011)) Microsurgery can require a hospital stay of up to 3 to 15 days.

Patient satisfaction is high with radiation treatments.(Lustgarten, 2013)

3.5. Patient Refusal of Surgery(Husseini, 2013)



4. Questions to Ask Your Doctor

There is a list of factors that should be discussed with your doctors before having radiation treatment. You should feel comfortable enough with the medical team you plan to allow to treat you, to ask and make sure they understand your questions and concerns.

The list is extensive and you may only want to discuss some of the questions as others might not apply to your situation. For example, you may not have an implant. These points are meant as a guideline only. You should ask questions that occur to you that aren't on the list also. Feel free to print the checklist out and take it with you to your appointments. Take a pen or pencil with you to take notes! Being prepared and knowing what to expect can help reduce anxiety and stress in children as well as adults.

  1. Is the tumor to be treated a Lobular Schwannoma? If yes, despite the odd shape; 1) will the center of the mass be easy to find to kill all the cells in the tumor, 2) wouldn't that increase the possibility of brain cell death and 3) what brain function issues might be at risk with risk of brain cell death?
  2. The pros and cons of the treatments for; 1) SRS, 2) FSR, and 3) Conventional therapy.
  3. How is my head immobilized during treatment, is a face-mask used, how long does the treatment last, does it hurt, will I be sedated, will I go to recovery after the procedure, what can I expect; 1) immediately after, 2) days, 3) weeks, 4) months after treatment?
  4. The effectiveness of the treatment including actual percentages, the chances of initial swelling, the chances of regrowth and ease or difficulty of surgery on a previously irradiated tumor.
  5. How soon after treatment would it take before an MRI would be able to confirm success?
  6. Does the area around the tumor have enough room to accommodate initial swelling of the tumor without causing complications?
  7. The percentage chance that a tumor might become malignant as well as the chance that other tumors may be negatively affected due to the genetics of NF2 gene.
  8. RIN (radiation induced necrosis) effects of the therapy, chances that they will occur and what can be done if they do occur. Will RIN require surgery?
  9. Will I be given steroids before, during or after treatment to try to minimize swelling?
  10. Possible negative cognitive effects explained.
  11. If the patient is a child or young adult, what are the possible consequences of treating a still developing brain?
  12. Nerve damage, hearing implant damage and permanent hair loss. How likely are they to occur?
  13. Is the tumor inoperable? If no then am I healthy/young enough for surgery should I need it later?
  14. Let your doctors know if you are claustrophobic.
  15. How long after the procedure will my case be followed? Months, years, decades?
  16. Do the benefits outweigh the risks in your case? Why chose radiation over surgery in your case?


5. Reference Sources

  1. AFRRI Staff. "What is Ionizing Radiation?" Armed Forces Radiobiology Research Institute. Last modified 2014. http://www.usuhs.edu/afrri/outreach/ionizing.htm

  2. Appleby, Alan, Martin Costello, and Steven Rose. "What Are the Sources of Ionizing Radiation?" Rutgers Environmental Sciences Training Center. Last modified November, 1996. http://www.nj.gov/dep/rpp/llrw/download/fact03.pdf

  3. Amichetti, Maurizio, Dante Amello, and Giuseppe Minniti. "Radiosurgery with photons or protons for benign and malignant tumours of the skull base: a review." Radiation Oncology 7, no. 210 (2012): Accessed February 22, 2014. http://www.ro-journal.com/content/7/1/210

  4. Cancer Connect.com. "Side Effects and Complications of Radiation Therapy for Brain Tumors." Cancer Consultants.com. Last modified 2014.

  5. Claus, E. B., Calvocoressi, L., Bondy, M. L., Schildkraut, J. M., Wiemels, J. L., & Wrensch, M. (2012). Dental x-rays and risk of meningioma. Cancer, 118(18), 4530-4537. http://onlinelibrary.wiley.com/doi/10.1002/cncr.26625/full

  6. Delannes, M, JP Maire, J. Sabatier, and F. Thillays. "Stereotactic radiotherapy for intracranial meningioma." Cancer radiotherapie (France) 16 (2012): 79-89. Accessed February 23, 2014 http://www.sciencedirect.com/science/article/pii/S1278321812000662

  7. Department of Nursing. "Radiation Therapy to the Brain." University of Wisconsin Hospitals and Clinics Authority. Last modified August 16, 2011. http://www.uwhealth.org/healthfacts/B_EXTRANET_HEALTH_INFORMATION-FlexMember-Show_Public_HFFY_1126650982462.html

  8. Dirks, M. S., Butman, J. A., Kim, H. J., Wu, T., Morgan, K., Tran, A. P., ... & Asthagiri, A. R. (2012). Long-term natural history of neurofibromatosis Type 2-associated intracranial tumors: Clinical article. Journal of neurosurgery, 117(1), 109-117. http://thejns.org/doi/abs/10.3171/2012.3.JNS111649

  9. Evans, DG R., J. M. Birch, and M. E. Baser. "Malignant transformation and new primary tumours after therapeutic radiation for benign disease: substantial risks in certain tumour prone syndromes." Journal of Medical Genetics 43, no. 4 (2009): 289-294. Accessed February 22, 2014. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2563223/

  10. Friedman, RA, DE Brackman, WE Hitselberger, MS Schwartz, Z. Iqbal, and KI Berliner. "Surgical salvage after failed irradiation for vestibular schwannoma." Laryngoscope 115, no. 10 (2005): 1827-1832. Accessed February 23, 2014. http://www.ncbi.nlm.nih.gov/pubmed/16222204

  11. Husseini, ST, E. Piccirillo, A. Taibah, T. Almutair, G. Sequino, and M. Sanna. "Salvage surgery of vestibular schwannoma after failed radiotherapy: the Gruppo Otologico experience and review of the literature." American Journal of Otolaryngology 34, no. 2 (2013): 107-114. Accessed February 23, 2014. http://www.ncbi.nlm.nih.gov/pubmed/23177377

  12. Hladik, D., & Tapio, S. (2016). Exposure of ionizing radiation on the mammalian brain: Epidemiological evidence, pathological and molecular effects and prevention strategies. Mutation Research/Reviews in Mutation Research. http://www.sciencedirect.com/science/article/pii/S1383574216300965

  13. Johnson, Mahion D., Burak Sade, Michael T. Milano, Joung H. Lee, and Steven A. Toms. "New prospects for management and treatment of inoperable and recurrent skull base meningiomas." Journal of Neurooncology 86 (2008): 109-122. http://link.springer.com/article/10.1007/s11060-007-9434-z#page-2

  14. Kim, Young Z., Dae Y. Kim, and Seung H. Lee. "Radiation-induced Necrosis Deteriorating Neurological Symptoms and Mimicking Progression of Brain Metastasis after Stereotactic-guided Radiotherapy." Cancer Research and Treatment 39, no. 1 (2007): 16-21. Accessed February 22, 2014. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2739359/

  15. Lustgarten, Leonardo. "The impact of stereotactic radiosurgery in the management of neurofibromatosis type 2-related vestibular schwannomas." Surgical Neurology International 4, no. 3 (2013): S151-S155. Accessed February 23, 2014. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3654776/

  16. National Institute on Deafness and other Communication Disorders(NIDCD). "Vestibular Schwannoma (Acoustic Neuroma) and Neurofibromatosis." Last modified June 7, 2010. https://www.nidcd.nih.gov/health/hearing/pages/acoustic_neuroma.aspx#diagnosed

  17. National Institutes Of Health (NIH). "Radiation Therapy for Cancer Fact Sheet." National Cancer Institute (NCI). Last modified June 20, 2010. http://www.cancer.gov/cancertopics/factsheet/Therapy/radiation

  18. Mandigo, C. E., & McCormick, P. C. (2012). Asymptomatic Intradural Schwannoma: Surgery Versus Radiosurgery Versus Observation. Best Evidence for Spine Surgery: 20 Cardinal Cases (Expert Consult-Online), 103. http://books.google.com/books?hl=en&lr=&id=wVgCSGT_ILoC&oi=fnd&pg=PA103&dq=NF2,+when+to+remove+Schwannoma,+spinal+cord&ots=wwRrfAs-2S&sig=-IrrTfFsIIHp6e3J1R3lxXOl5XI

  19. Plotkin, Scott R., Marybeth A. Singh, Caroline C. O'Donnell, Gordon J. Harris, Andrea I. McClatchey, and Chris Halpin. "Audiologic and radiographic response of NF2-related vestibular schwannoma to erlotinib therapy." Nature Clinical Practice Oncology 5 (2008): 487-491. Accessed February 23, 2014. http://www.nature.com/nrclinonc/journal/v5/n8/full/ncponc1157.html

  20. Ronca, Debra. "How Radiation Works." How Stuff Works. Accessed February 23, 2014. http://science.howstuffworks.com/radiation2.htm

  21. Stanuszek, A, PZ Piatek, S. Kwiatkowski, and D. Adamek. "Multiple faces of children and juvenile meningiomas: A report of single-center experience and review of literature." Cliniical Neurology and Neurosurgery 118 (2014): 69-75. Accessed February 23, 2014. http://www.ncbi.nlm.nih.gov/pubmed/24529233

  22. Terrier, L. M., & François, P. (2016). [Multiple meningiomas]. Neuro-Chirurgie. http://europepmc.org/abstract/med/27234913
  23. UT Department of Neurology. "Acoustic Neuromas: What You Should Know." The University of Texas Health Science Center at San Antonio. Last modified May 11, 2011. http://neurosurgery.uthscsa.edu/display_patients.php?ps_id=33&pg=patient_services.php.

  24. Wiemels, J., Wrensch, M., & Claus, E. B. (2010). Epidemiology and etiology of meningioma. Journal of neuro-oncology, 99(3), 307-314. http://link.springer.com/article/10.1007/s11060-010-0386-3#page-1

  25. WNN - World Nuclear News. World Nuclear Association. What is radiation? http://www.world-nuclear.org/Nuclear-Basics/What-is-radiation-/

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