The five- year KRAS, NRAS and BRAF analysis results and treatment patterns in daily clinical practice in Slovenia in 1st line treatment of metastatic colorectal (mCRC) patients with RAS wild-type tumour (wtRAS)– a real- life data report 2013-2018

Abstract

Background. This was a Phase IV non-interventional study to assess KRAS, NRAS and BRAF status in mCRC patients (pts) suitable for 1^st line treatment and evaluation of decisions for 1^st line treatment considering the treatment goals in the RAS wild type (wt) pts.

Patients and methods. Pts with histologically confirmed mCRC adenocarcinoma suitable for first-line treatment fulfilling all inclusion criteria were included in the study. The KRAS, NRAS and BRAF analysis was performed from tissue samples of primary tumor site or metastatic site. All included pts has given consent to participate in the study by signing the informed consent form.

Results. From April 2013 to March 2018 at the Institute of Oncology Ljubljana 650 pts were included, 637 of them were treated with first- line systemic treatment according to RAS and BRAF status. Remaining 13 pts with mCRC did not receive systemic first-line treatment. The distribution of pts with KRAS mutated and wild-type tumors, was almost equal, 48.8% and 47.9% respectively, 89 % of the patients had wt NRAS tumours and 86.1% had wt BRAF tumours. The most frequently prescribed treatment was bevacizumab- based therapy (53.1%), either in combination with doublet chemotherapy or with mono- chemotherapy. EGFR inhibitors cetuximab and panitumumab were prescribed in wt RAS mCRC pts (30.9%). 

Conclusions. Our real-world data, single centre 5-year analysis showed that the distribution between wild type and mutated type tumors of the pts with mCRC was approximately the same, as worldwide, so the Slovenian population with mCRC has the same ratio distribution of KRAS, NRAS and BRAF wild and mutated genes. We concluded that a two-week waiting period for biomarkers analysis did not influence the first line treatment decision, so it was in the accordance with the worldwide treatment guidelines based on evidence-based medicine.