Treatment choices in metastatic colorectal cancer according to sidedness and RAS/BRAF status: a national survey by the Brazilian Gastrointestinal Tumors Group (GTG)

Abstract

Objectives: Tumor sidedness and RAS/BRAF status have changed the treatment landscape of metastatic colorectal cancer (mCRC). This study was performed to understand the first line choices of Brazilian oncologists for patients with mCRC, especially in the emergent context of tumor sidedness and RAS/BRAFV600E status. Methods: This was a cross-sectional electronic survey composed of six questions sent to Brazilian medical oncologists through social media. The survey instrument collected demographic data of participants and assessed current practices in terms of first-line treatment choices for fit patients with mCRC. Participants with at least 50% of their clinical practice dedicated to patients with GI malignancies were deemed GI specialists. Results: The survey was completed by 239 medical oncologists from across the country. Most oncologists were male (59%) and were in oncology practice for less than 10 years (62.2%). Only 20.9% of the participants were specialists in GI tumors. For left-sided, wild-type (wt) RAS/wt-BRAFV600E mCRC, most oncologists (82%) chose first line chemotherapy (CT) + anti-EGFR therapy, with 53.6% of them preferring FOLFIRI as the CT backbone. Meanwhile, for right-sided, wt-RAS/wt-BRAFV600E mCRC, the majority (70.7%) would offer CT + bevacizumab (53.9% with FOLFOX). For mutated-RAS mCRC, most oncologists decided for FOLFOX + bevacizumab (51.9%). Subgroup analyses revealed statistically significant differences for therapeutic choices in first line for left-sided wt-RAS/wt-BRAFV600E mCRC: female oncologists prefer FOLFOX as CT backbone ( p= 0.004) and in right-sided wt-RAS/wt-BRAFV600E mCRC, GI cancer specialists more often use FOLFOXIRI and bevacizumab (18 vs 7.9%; p= 0.001). Conclusion: Our survey indicates that tumor sidedness influences the choice of both CT backbone and monoclonal antibody in unresectable wt-RAS mCRC. In addition, oncologists' gender and percentage of time dedicated to treat GI cancers also impacted on therapeutic choices for mCRC in Brazil.

Keywords

• Colorectal neoplasms
• Surveys and questionnaires
• Antineoplastic agentes.
• Neoplasias colorretais
• Pesquisas e questionários
• Antineoplásicos.