Despite technological advances, median survival for GBM is 12-15 months. Epidermal growth factor receptor (EGFR) gene represents signature genetic abnormalities in GBM.
EGFR status and other prognostic factors in primary GBM patients aged ≥18 years with performance status ECOG ≤3 with no other co-morbid illness, who underwent gross total excision and undergoing adjuvant post-operative radiation concurrent with Temozolomide were analyzed for Median Recurrence Free Survival (RFS) and Median Overall Survival (OS).
Our study population was characterized by median age of 56.91 Â± 11.2 (Range: 38-76 years) with a male gender 25 (56.8%) and female 19 (43.2%) having a performance status ECOG 1 in 20 (45.45%), ECOG 2 in 16 (36.36%) and ECOG 3 in 8 patients (18.18%); 26 (59%) were not having any neurological deficit and 18 (41 %) had neurological deficits. The tumor was distributed at Right hemisphere in 18 (40.91%), left hemisphere in 25 (56.82%) and bilateral in 1 (2.27%) patient at Frontal lobe in 11 (25 %), Parietal lobe in 16 (36.36 %), Temporal lobe in 14 (31.82 %) and Occipital lobe in 3 patients (6.82 %). EGFR expression measured quantitatively showed 1+ positivity in 4 (9.09%), 2+ in 11(25%), 3+ in 7 (15.91%) and 4+ in 6 (13.64%), negative in 16 patients (36.36 %). EGFR expression measured qualitatively was weak in 8 (18.18%), Intermediate in 11 (25%), Strong in 9 (20.45%) and negative in 16 patients (36.36 %). Recurrence was observed in 12 patients (27.3%). RFS was 15 months and OS 12 months. Age, Gender, Performance Status, Neurological Status and EGFR expression had no statistically significant impact on RFS or OS. EGFR expression - Negative group had more recurrences compared to 4+ cohorts, but the time to recur was longer in Negative compared to others. Qualitative EGFR expression - “Strong” group had lesser recurrences compared to others.
There was no statistically significant impact based on Age, Gender, Performance Status, Neurological Deficit and EGFR status both by quantity and quality for the RFS or OS. Focal mitoses and Endothelial Proliferation were significantly associated with recurrences but not OS. The relationship of EGFR positivity, treatment response, RFS and OS being complex need further evaluation.
Clinical trial identification
All authors have declared no conflicts of interest.