BlueCross BlueShield of Tennessee Medical Policy Manual

Tumor-Treatment Fields Therapy for Glioblastoma


Tumor-treatment fields (TTF) therapy (e.g., Nova TTF-100A™ System, Optune® System) is a noninvasive technology intended to treat glioblastoma on an outpatient basis using electric fields.  TTF therapy exposes cancer cells to alternating electric fields of low intensity and intermediate frequency, which are purported to both selectively inhibit tumor growth and reduce tumor angiogenesis.   Tumor treatment fields are proposed to inhibit rapidly dividing tumor cells by two mechanisms: arrest of cell proliferation and destruction of cells while undergoing division.

The battery-powered portable device generates the electrical fields via disposable electrodes that are noninvasively attached to the individual’s shaved scalp over the site of the tumor.  The device is used by the individual at home on a continuous basis (20 - 24 hours per day) for the duration of treatment which can last for several months.

Glioblastomas are a type of astrocytoma and the most common form of malignant primary brain tumor in adults. Typically found in the supratentorial region (frontal, temporal, parietal, and occipital lobes). They comprise approximately 15 percent of all brain and central nervous system tumors and over 50 percent of all tumors that arise from glial cells. The primary treatment for GBM is debulking, or surgical reduction in size, to remove as much of the tumor as possible. For individuals with recurring disease after the initial therapies, additional debulking surgery may be used if recurrence is localized.

Depending on the individuals physical condition, adjuvant radiation therapy, chemotherapy or a combination of the two are sometimes given.  A Karnofsky Performance Status (KPS) score can be used to determine appropriate therapy. The score is a simple tool to assess the functional status of the individual ranging from 0 to 100; describing the ability to carry on normal activity and work, or need for custodial care, or his dependence on constant medical care. The higher the individual’s score, the greater the functional level.





Karnofsky Performance Status*


% Score


A: Able to carry on normal activity and to work. No special care is needed


Normal, no complaints, no evidence of disease.



Able to carry on normal activity, minor signs or symptoms of disease.



Normal activity with effort, some signs or symptoms of disease.

B: Unable to work. Able to live at home, care for most personal needs. A varying degree of assistance is needed.


Cares for self, unable to carry on normal activity or to do active work.



Requires occasional assistance, but is able to care for most of his needs.



Requires considerable assistance and frequent medical care.

C: Unable to care for self. Requires equivalent of institutional or hospital care. Disease may be progressing rapidly.


Disabled, requires special care and assistance.



Severely disabled, hospitalization is indicated although death not imminent.



Hospitalization necessary, very sick, active supportive treatment necessary.



Moribund, fatal processes progressing rapidly.





*Original text of Karnofsky and Burchenal (1949).

Based on the small amount of published evidence and the lack of demonstrated treatment benefit to date, further evidence from high-quality trials is needed to assess the efficacy of electrical fields therapy for the treatment of recurrent glioblastoma.


BlueCross BlueShield Association. Evidence Positioning System. (6:2018). Tumor treatment fields therapy (1.01.29). Retrieved October 15, 2018 from (16 articles and/or guidelines reviewed)

ECRI Institute. Emerging Technology Evidence Report. (2016, July). Tumor treating fields therapy (Optune) for recurrent glioblastoma. Retrieved August 31, 2016 from ECRI Institute. (69 articles and/or guidelines reviewed)

National Comprehensive Cancer Network. (2018, March). NCCN Clinical Practice Guidelines in Oncology. (NCCN Guidelines®). Central nervous system cancers (V.1.2018). Retrieved October 15, 2018 from

Peus, D., Newcomb, N, and Hofer, S. (2013) Appraisal of the Karnofsky Performance Status and proposal of a simple algorithmic system for its evaluation. BMC Medical Informatics & Decision Making. 13 (72). (Level 5 evidence)

Rulseh, A. M., Keller, J., Klener, J., Šroubek, J., Dbalý, V., Syrůček, M., et al. (2012). Long-term survival of patients suffering from glioblastoma multiforme treated with tumor-treating fields. World Journal of Surgical Oncology, 10 (220). (Level 4 evidence)

Stupp, R., Taillibert, S., Kanner, A., Kesari, S., Steinberg, D., Toms, S., et al. (2015). Maintenance therapy with tumor-treating fields plus temozolomide vs temozolomide alone for glioblastoma - a randomized clinical trial. Journal of the American Medical Association, 314 (23), 2536-2545. (Level 2 evidence)

Stupp, R., Wong, E. T., Kanner, A. A., Steinberg, D., Engelhard, H., Heidecke, V., et al. (2012). NovoTTF-100A versus physician's choice chemotherapy in recurrent glioblastoma: A randomised phase III trial of a novel treatment modality. European Journal of Cancer, 48 (14), 2192-2202. (Level 4 evidence)

U. S. Food and Drug Administration. (2015, October). Center for Devices and Radiological Health. Pre-market approval decisions for October 2015.  P100034/S013. Retrieved August 31, 2016 from

Winifred S. Hayes, Inc. Medical Technology Directory. (2016, March). Novocure (tumor treating fields). Retrieved June 3, 2016 from (37 articles and/or guidelines reviewed)

Wong, E., Lok, E., & Swanson, K. (2015) An evidence-based review of alternating electric fields therapy for malignant gliomas. Current Treatment Options in Oncology, 2015, 16 (40), 1-11. (Level 4 evidence)

Zhu, P. and Zhu J. (2017, August) Tumor treating fields: a novel and effective therapy for glioblastoma: mechanism, efficacy, safety and future perspectives. Chinese Clinical Oncology, 6 (4), 41. Abstract retrieved September 18, from PubMed database.




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