- Metastatic tumor bulk and right-sidedness of the primary tumor are tied to poorer OS with late-line anti-epidermal growth factor receptor (EGFR) therapy for metastatic colorectal cancer (mCRC).
- Patients with right-sided primary tumors presented with increased tumor bulk.
Why this matters
- Future studies should examine metastatic tumor bulk alongside molecular profiling to help determine which patients may benefit from late-line anti-EGFR therapy.
- Retrospective, single-center analysis of 62 KRAS wild-type patients with mCRC treated with late-line anti-EGFR therapy.
- Funding: National Cancer Institute.
- 15 of 47 tumors were right-sided. Right-sided patients were older (mean, 69 vs 59 years; P=.04) and had larger metastases (mean largest diameter, 52.7 vs 28.5 mm; P=.03) and worse OS (6.8 vs 16.7 months; P=.047).
- After correction for primary tumor location, bulky disease (defined as any single lesion ≥35 mm in longest cross-sectional diameter or nodal short axis), was associated with:
- Worse survival with anti-EGFR therapy (6.0 months vs 16.0 months; P=.006).
- Worse PFS (3.5 vs 7.2 months; P=.001).
- Worse objective response rate (9.5% vs 38.7%; P=.044).
- Worse OS (6.0 vs 23.4 months; P<.001>
- Retrospective, single-center.