Diagnosis: Oligometastatic lesion in the abdominal wall
Treatment: SBRT
The SBRT is medically necessary.

Stereotactic radiosurgery (SRS) is a highly precise form of radiation therapy used primarily to treat tumors and other abnormalities of the brain. The treatment involves the delivery of a single high-dose, or sometimes smaller, multiple doses, of radiation beams that converge on the specific area where the tumor or other abnormality resides.   It is a highly precise treatment, is able to minimize the amount of radiation to surrounding healthy and critical tissues.  Extracranial stereotactic radiosurgery or stereotactic body radiotherapy (SBRT) for certain conditions has also been shown to be safe and effective as compared to the standard radiation therapy.  Some of the conditions that have shown the most potential include spinal tumors, liver tumors and inoperable stage I lung cancers.  Other conditions include re-treatment of previous treated areas where conventional radiation in is inadequate in sparing surrounding normal tissues.  SBRT is FDA-approved.  It is not subject to IRB (institutional review board) review, and its effectiveness has been proven based on clinical evidence reported in peer-reviewed medical literature.

In this case, the patient is a male with a history of lung cancer s/p definitive chemoradiotherapy.  The patient developed brain metastasis s/p resection.  The patient was recently found to have an oligometastatic lesion in the abdominal wall.   Local therapy to the oligometastatic abdominal wall lesion was recommended, and stereotactic body radiosurgery was requested.  

There is clinical data demonstrating the safety and effectiveness of stereotactic radiosurgery for oligometastatic lesions.  In fact, SBRT may provide a better local control compared to standard fractionated radiation therapy.  

A 2013 review article by Tree et al. evaluated studies on SBRT for oligometastatic disease.  The authors stated, "Many non-randomised studies have shown that SBRT for oligometastases is safe and effective, with local control rates of about 80%", and concluded that "SBRT offers durable local control and the potential for progression-free survival in non-liver, non-lung oligometastatic disease at a range of sites."

In addition, a 2019 multi-institution randomized trial (SABR-COMET trial) randomized 99 patients with oligometastatic lesions (1-5 lesions) into control group vs SBRT.  Median overall survival was 28 months in the control group versus 41 months in the SABR (SBRT) group (p=0090). Treatment-related deaths occurred in three (45%) of 66 patients after SABR, compared with none in the control group.  The authors concluded, "SABR (SBRT) was associated with an improvement in overall survival, meeting the primary endpoint of this trial."

This patient has an oligometastatic abdominal wall lesion with any active disease elsewhere, and if they are controlled with SBRT, the patient may have a prolonged survival.  Stereotactic radiosurgery has been shown to be safe and effective for the treatment of oligometastatic/solitary lesions, and in this case, is the best option that can help with disease control.  Stereotactic body radiotherapy (SBRT) is, therefore, considered medically necessary for this patient at this time.