Abstract 103P
Background
This retrospective study examines the prognostic significance of relative versus absolute neutropaenia in patients receiving GemCarbo chemotherapy, proposing neutropaenia as a surrogate biomarker of appropriate drug dose to the individual patient. The prognostic relevance of relative neutropaenia in this cohort has not previously been explored.
Methods
All consecutive patients undergoing at least one cycle of GemCarbo chemotherapy for NSCLC in the North Wales Cancer Treatment Centre between 2007 and 2016 were included in this retrospective analysis. Absolute neutropaenia was classified using Common Terminology Criteria for Adverse Events grading, and grouped as none (grade 0), moderate (grade 1-2) and severe (grade 3-4). Relative neutropaenia was calculated using the formula (ND21-ND1)/ND1, with ND1 being neutrophils on day 1, and categorised in terciles. Multivariate analysis using Cox proportional regression hazard models controlled for age, gender, performance score (PS) and metastatic status.
Results
There were 248 patients in this cohort, 109 (44%) had metastatic disease at diagnosis, 237 (95.6%) subsequently died. Median age was 67 years [44 to 83], and PS distribution was: 0=42.8%; 1-2= 54.3%; 3-4=2.9%. On Day 21 of chemotherapy, 43.4% of our patients exhibited absolute and 94% relative neutropaenia. Moderate relative neutropaenia (middle tercile) was associated with improved OS, after adjusting for other prognostic factors (HR= 0.67; 0.47-0.96, p=0.03). Thus, median OS (months) was 12.3, 22.1 and 12.6 according to relative neutropaenia terciles. Absolute neutropaenia was not statistically significant at multivariate analysis.
Conclusions
Relative neutropaenia may be a more useful prognostic indicator than absolute neutropaenia in NSCLC patients undergoing GemCarbo chemotherapy. Our results indicate that a moderate level of neutropaenia predicts for prolonged overall survival in this cohort, suggesting that appropriate drug dosage could be tailored to obtain moderate neutropaenia in order to maximize patient benefit.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
North Wales Cancer Treatment Centre.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.