MA: Charged Particle Radiation, Helium Ion or Proton and Stereotactic Radiosurgery

Description 

Stereotactic radiosurgery (SRS) refers to the delivery of a single very limited number of relatively large doses of radiation administered to a small, precisely defined target. This is achieved by using multiple, non-parallel radiation beams that converge on the target lesion. The full therapeutic dose is limited to the area where all of the beams overlap, while non-target areas receive much smaller doses from one or a limited number of radiation beams. SRS thus requires accurate localization of the lesion and patient positioning during treatment. 

SRS may offer a non-invasive alternative to invasive surgery, particularly for patients unable to undergo surgery or for lesions that are difficult to access surgical or are adjacent to vital organs. 

Cranial stereotactic radiosurgery (SRS) is a method of delivering high doses of precisely targeted ionizing radiation to intracranial lesions. 

SRS, when used extracranially, is called stereotactic body radiation therapy (SBRT). Platforms available for SRS and SBRT are distinguished by their source of radiation: they include gamma radiation from cobalt 60 sources; high energy photon from LINAC systems; and particle beams (protons). 

Fractionated stereotactic radiotherapy refers to when SRS or SBRT is performed more than one time on a specific site. SBRT is commonly delivered over 3-5 fractions. SRS is most often single-fraction treatment; however, multiple fractions may be necessary when lesions are near critical structures, tumors have an unusual shape or when high-dose single fraction treatment could not be tolerated. 

Many patients with brain metastases can either receive whole brain radiotherapy (WBRT) along with SRS or WBRT may be delayed for use as salvage therapy for recurrent intracranial disease. 

Proton beam radiation therapy (PBRT) is a type of radiotherapy using protons rather than photons used in traditional external beam radiation therapy. Proton beam radiation therapy (PBRT) is also known as intensity-modulated proton therapy (IMPT), proton therapy and proton beam radiotherapy. PBRT has been used for the treatment of tumors that would benefit from the delivery of high dose or radiation with limited scatter. 

Policy 

1. Stereotactic radiosurgery (SRS) using a gamma knife, cyberknife, or Linac (linear accelerator) may be considered scientifically validated for ANY of the following indications: 
   
   1. acoustic neuroma (vestibular schwannomas) OR 
   2. arteriovenous malformations OR 
   3. craniopharyngioma OR 
   4. glomus jugulare tumors (hypervascular tumor that arises within the jugular foramen of the temporal bone) OR 
   5. malignancies of the CNS (gliomas, astrocyomas) OR 
   6. solitary or multiple brain metastases, in patients with a good performance status and no systemic disease (Karnofsky performance scale of at least 70) and extracranial disease that is stable or in remission OR 
   7. meningiomas that are nonresectable, residual, or recurrent OR 
   8. pituitary adenoma OR 
   9. trigeminal neuralgia that is refractory to medical management OR 
   10. mesial temporal lobe epilepsy refractory to medical management when standard alternative surgery is not an option OR 
   11. uveal melanoma 
2. All other indications for stereotactic radiosurgery (SRS) using a gamma knife, cyberknife, or Linac (linear accelerator) are considered Investigational. 
3. Stereotactic Body Radiotherapy (SBRT) / Stereotactic Ablative Body Radiotherapy (SARB) may be considered scientifically validated for ANY of the following indications: 
   
   1. non-small cell lung cancer, Stage 1, in patients who are not candidates for surgery for who refuse surgery after informed consent. 
   2. non-small cell lung cancer, with oligometastasis, i.e. 1-3 metastatic lesions, when ALL of the following are met: 
      
      1. definitive RT to the oligometastasis is planned AND 
      2. radical therapy to the intrathoracic disease is planned or has been received AND 
      3. metastatic sites are in the lung and/or adrenal gland AND 
      4. patient has good performance status i.e. Karnofsky performance status (KPS) of at least 70 
   3. oligometastasis to the lung from a cancer of unknown primary (NCCN also refers to this as occult primary), when ALL of the following are met: 
      
      1. metastatic lesions are present in the lungs AND 
      2. patient has good performance status i.e. Karnofsky performance status (KPS) is at least 70 
   4. spinal tumors, primary- that cause intractable pain or spinal cord compression 
   5. spinal tumors, primary or metastatic - in patients who have received previous radiotherapy (RT) 
   6. spinal tumors, metastatic- that are radio-resistant e.g. renal cell cancer, melanoma, sarcoma 
   7. primary or metastatic tumors of the liver as an alternative locoregional treatment for patients with inoperable primary or metastatic lesions. 
   8. primary renal cell carcinoma in patients who are not good surgical candidates or for metastatic renal carcinoma 
   9. pancreatic cancer without invasion of bowel or stomach 
   10. prostate cancer when ALL of the following are met: 
       
       1. low grade prostate cancer with a Gleason score of less than or equal to 6 and a PSA less than 10 ng/ml AND 
       2. minimal disease with less than four cores positive, AND 
       3. no evidence of extra prostatic disease AND 
       4. life expectancy is greater than 10 years 
   11. oligometastatic prostate cancer with 1-3 metastatic lesions 
   12. oligometastatic breast cancer with 1-3 metastatic lesions 
4. All other indications for Stereotactic Body Radiotherapy (SBRT)/ Stereotactic Ablative Body Radiotherapy (SABR) are considered Investigational. 
5. Fractionation is considered medically necessary when it is used to deliver stereotactic radiosurgery (SRS) or stereotactic body radiation (SBRT) for the medically necessary indications described above. 
6. Charged-particle irradiation with proton or helium ion beams may be considered scientifically validated for ANY of the following indications: 
   
   1. melanoma of the uveal tract (iris, choroid, or ciliary body) with no evidence of extrascleral extension or metastasis OR 
   2. chordomas or chondrosarcomas arising at the base of the skull or cervical spine without distant metastases OR 
   3. pediatric central nervous system tumors. 
7.  All other indications for Charged-particle irradiation with proton or helium ion beams are considered Investigational.

Karnofsky Performance Status Scale 

Stereotactic guidance: precision in target localization is a prerequisite for successful SRS. 

This can be accomplished through the attachment of a stereotactic head frame using four pins that attach to the outer table of the skull. The head frame placement is usually done with local anesthesia, although sedation may be required. 

After placement of a head frame, high resolution computed tomography (CT) or magnetic resonance imaging (MRI) is obtained to visualize its four posts. Spatial coordinates for the lesion are calculated relative to these landmarks. During the RT session, the frame is bolted to the treatment couch to immobilize the patient, allowing precise targeting of the radiation. The patient is treated on the same day that the head frame is placed. 

Frameless radiosurgery is a reasonable option for palliative treatment of malignant disease, larger lesions, and mulitfraction treatments. 

Codes