Recently, sidedness and BRAF status of mCRC has been discussed most because they have strong correlations with the treatment effects and prognosis. In several trials, exploratory analyses showed no positive prognostic effect of 1st-line antiEGFR antibody in mBRAF mCRC. However, in clinical setting, we often encounter effective cases of antiEGFR antibody in mBRAF mCRC.
50 patients(pts) with RAS wild mCRC treated with 1st-line mFOLFOX6+anti- EGFR antibody between 5/2012 and 3/2017 were retrospectively analyzed. Median age: 64(41-83). Gender: male 31, female19. Performance status (PS):0-1 48pts, >2 2 pts. Sidedness: Rt-s tumor 12 pts, Lt-s tumor 38(including 17 rectal pts). 7 pts had mBRAF (14%, 5 sRt pts, 2 sLt pts).
The median follow-up time was 28 months(m) (IQR, 14-52). Overall mOS was 29.2m (95%CI; 20.4-32.6), and mPFS was 12.0m (95%CI; 8.0-17.0). Partial responses (PR by RECIST1.1) and early tumor shrinkages (ETS) were observed in 70.5% pts. In the analysis of sidedness and BRAF: mOS; sRt 24.5m, sLt 29.2m (HR 0.683, p = 0.503), sRt mBRAF 20m. ETS; sRt 41.7%, sLt 81.3%, sRt mBRAF 20% (1/5 case). In this sRt mBRAF patient with positive ETS, hepatic metastases were excised after achieving PR by 1st-line mFOLFOX6+antiEGFR antibody, and he has survived 4 years after surgery without any sign of recurrence.
In sRt mBRAF mCRC, some patients show good responses to antiEGFR antibody, and a clinical biomarker is needed to distinguish such pts responsive to the 1st-line antiEGFR antibody. ETS, even though on treatment marker, might be one of the candidates of judging the efficacy.
Clinical trial identification
Legal entity responsible for the study
Kyoto Katsura Hospital.
Has not received any funding.
The author has declared no conflicts of interest.