Abstract 403P
Background
Treatment of mCRC is guided by clinical and molecular features which include side of primary, RAS, BRAF and MMR status. For left sided RAS WT mCRC survival is optimized by using first-line anti-EGFR anti-bodies combined with chemotherapy.
Methods
We aim to assess the use of first-line anti-EGFR/chemotherapy (FaEC) combinations in patients with mCRC and assess for differences between cetuximab (C) and panitumumab (P) using the SA mCRCR. This real word registry has collected data from all patients diagnosed with mCRC in SA prospectively since 2/2006. We compared C and P in RAS WT patients, and those treated with bevacizumab (B) from 2006 and those treated since January 2015 when FaEC was funded in Australia. Survival was analysed using the Kaplan Meier method.
Results
Of the 5537 patients currently entered onto the registry, 1313 had RAS status recorded and 245 received FaEC (167/68% since 2015). 1068 patients received B (52% KRAS WT). Table summarises patient characteristics and median OS for FaEC (C or P) and B. Overall there was no statistical difference in survival for C v P (p=0.125). Patients entered from 2015 had mostly similar patient characteristics including significant use in right sided primary (24% v 20% respectively). Table: 403P
| Chemo/C (139) | Chemo/P (106) | Chemo/B (1068) | |
| Median age (range) | 65.3 yrs (24-87) | 60.1 yrs (26-89) | 64.6 (20.5-93) |
| Male | 66.2% | 64% | 61% |
| Oxaliplatin | 15% | 43.4% | 70% |
| Irinotecan | 59% | 46.2% | 15.5% |
| Stage 4 at diagnosis | 47.5% | 64.2% | 67.5% |
| Left primary | 65.5% | 77.4% | 58% |
| Liver mets only | 38.1% | 42.5% | 37.2% |
| Lung mets only | 5.8% | 9.4% | 8.7% |
| BRAF MT | 7.9% | 2.8% | 7.3% |
| Liver resection | 6.5% | 14.2% | 9.8% |
| Median OS (95% CI) | 21.6 mths (16.7-26.4) | 25.3 mths (20.8-29.7) | 22.7 mths (21-23.9) |
Conclusions
When comparing C & P in first-line therapy, C was more often combined with irinotecan chemo. There were lower rates of liver resection and higher right primary and BRAF MT in patients treated with C which may explain the numerically lower median overall survival.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Adelaide Colorectal Tumour group.
Funding
Has not received any funding.
Disclosure
T.J. Price: Financial Interests, Personal, Invited Speaker, Symposium: Servier; Financial Interests, Personal, Advisory Board, Advisory role: Merck Serono; Financial Interests, Personal, Advisory Board, Global advisory board on MSS CRC: MSD; Non-Financial Interests, Advisory Role, Advisory board uncompensated: MSD. C.S. Karapetis: Financial Interests, Personal, Advisory Board: AstraZeneca, MSD, BMS, Ipsen, Eli Lilly, Eisai, Roche, Takeda, Beigene; Financial Interests, Institutional, Invited Speaker: Takeda, Roche, Mirati, Daiichi Sankyo; Non-Financial Interests, Member: Medical Oncology Group of Australia, American Society of Clinical Oncology. All other authors have declared no conflicts of interest.