Retrospective Review of the Factors Limiting Optune Initiation in GBM patients

Abstract

Tumor Treating Fields (TTFields) are a proven treatment that prolongs survival in Glioblastoma Multiforme (GBM) patients. The duration of usage of TTFields correlates with its effectiveness. This study aims to identify socioeconomic and clinical factors that prevent GBM patients at a single institution from starting and remaining on TTFields treatment. This is a retrospective review from a single institution. Data were analyzed for each patient with a diagnosis of GBM that was seen in new patient consultation with a radiation oncologist. Data from 2015 to present were available. 178 patients were included in the study. Insurance status (private vs Medicare/Medicaid vs uninsured), zip code, expected income status, race, ethnicity, preferred primary language, work status, performance status (KPS) at time of diagnosis, and family support at home (Spouse vs Other) were analyzed. For those that initiated TTFields, we examined the duration of treatment, usage rates, patient reported tolerability, and reasons for discontinuation. Early termination of treatment was defined as treatment with TTFields for less than 3 months. Of the 178 diagnosed GBM patients, 96 (54%) were offered TTFields and 48 (27%) agreed to treatment, with 46 actually starting. Of 89 Non-Hispanic patients, 53 were offered TTFields (60%) whereas of 73 Hispanic patients, 35 were offered TTFields (48%) (no statistically significant difference). The number one reason for refusing TTFields treatment was rapid deterioration (14/48 patients). The next most common reason was the patient feeling overwhelmed by managing or wearing the device (10/48) as well as the patient's decision to participate in any other clinical trial (10/48). The 3-month dropout rate for patients who received TTFields was 35% (17/48). 5 of the 17 stopped early due to skin rash or annoyance with the device. Patient's median income and insurance status did not predict whether they would start TTFields. 33 out of 109 (31%) patients with spousal support at home started treatment with TTFields compared to 13 of 69 (19%) of those without spousal support (p = .0895, Chi-Square test). TTFields were offered to more patients each successive year, but many patients had no documented discussion offering TTFields, which may indicate room for improvement at our institution. Median income and insurance status did not play a role in patient access to TTFields, most likely due to Novocure sponsorship of un- or under-insured patients. Among those who declined treatment, 21% did so because of perceived difficulty managing the device. The strongest single trend predictive of successful initiation of TTFields is spousal support at home. Further interventions may focus on improving patient support at home, such as home health nursing visits or community support.