Molecular Pattern and Clinical Implications of KRAS/NRAS and BRAF Mutations in Colorectal Cancer.

The aim of our study was to evaluate the incidence of KRAS/NRAS and BRAF mutations, analyze molecular patterns, and investigate associations with clinical parameters of these mutations in CRC KRAS/NRAS and BRAF mutations analyzed by next-generation sequencing. The detection rates of these mutations and patients' demographics were recorded and the relationship between them was evaluated using the chi-square test. KRAS mutation was detected in 332 of 694 patients, while the mutation rates in KRAS exons 2/3 and 4 were 39.6%/3.2% and 5%, respectively. The most common mutation pattern was KRAS G12D. Five atypical variants were detected: V14I in KRAS exon 2, A18D, Q22K and T50I in exon 3, and T148P in exon 4. NRAS mutation was detected in 29 (4.5%) patients. One atypical variant L80W was detected in NRAS exon 3. BRAF mutation was seen in 37 (5.3%) patients, with BRAFV600E (83.8%) being the most common mutation pattern. NRAS mutation was significantly more frequent in patients > 64 years of age, BRAF mutation in women, and NRAS/BRAF mutations in right colon tumors. Grouping BRAF mutations into BRAFV600E and BRAFnon-V600E and their analysis according to specific tumor localizations showed that all four BRAFnon-V600E mutations originated in the rectum. In our study, KRAS exon 2 and other RAS mutation rates were higher than in the literature, while the BRAF v.600E mutation rate was similar. NRAS and BRAF mutations were significantly more frequent in the right colon. BRAF mutation was more common in women and in the right colon.

Prognostic factors for regorafenib treatment in patients with refractory metastatic colorectal cancer: A real-life retrospective multi-center study.

Regorafenib, an oral multikinase inhibitor, has improved survival in metastatic colorectal cancer (mCRC) patients who have progressed on standard therapies. Our study aimed to evaluate prognostic factors influencing regorafenib treatment and assess the optimal dosing regimen in a real-life setting. We retrospectively analysed 263 patients with mCRC from multiple medical oncology clinics in Turkey. Treatment responses and prognostic factors for survival were evaluated using univariate and multivariate analysis. Of the patients, 120 were male, and 143 were female; 28.9% of tumors were located in the rectum. RAS mutations were present in 3.0% of tumors, while BRAF, K-RAS, and N-RAS mutations were found in 3.0%, 29.7%, and 25.9% of tumor tissues, respectively. Dose escalation was preferred in 105 (39.9%) patients. The median treatment duration was 3.0 months, with an objective response rate (ORR) of 4.9%. Grade ≥ 3 treatment-related toxicity occurred in 133 patients, leading to discontinuation, interruption, and modification rates of 50.6%, 43.7%, and 79.0%, respectively. Median progression-free survival (PFS) and overall survival (OS) were 3.0 and 8.1 months, respectively. RAS/RAF mutation (hazard ratio [HR] 1.5, 95% confidence interval [CI] 1.1-2.3; P = 0.01), pretreatment carcinoembryonic antigen (CEA) levels (HR 1.6, 95% CI 1.1-2.3; P = 0.008), and toxicity-related treatment interruption or dose adjustment (HR 1.6, 95% CI 1.1-2.4; P = 0.01) were identified as independent prognostic factors for PFS. Dose escalation had no significant effect on PFS but was associated with improved OS (P < 0.001). Independent prognostic factors for OS were the initial TNM stage (HR 1.3, 95% CI 1.0-1.9; P = 0.04) and dose interruption/adjustment (HR 0.4, 95% CI 0.2-0.9; P = 0.03). Our findings demonstrate the efficacy and safety of regorafenib. Treatment line influences the response, with dose escalation being more favorable than adjustment or interruption, thus impacting survival.

Real-world outcomes of pazopanib in metastatic soft tissue sarcoma: a retrospective Turkish oncology group (TOG) study.

AIM: Description of patient characteristics, effectiveness and safety in Turkish patients treated with pazopanib for metastatic soft tissue sarcoma (STS). PATIENTS AND METHODS: This multicenter study is based on retrospective review of hospital medical records of patients (≥ 18 years) treated with pazopanib for non-adipocytic metastatic STS at 37 Oncology clinics across Turkey. Objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS) and overall survival (OS) were evaluated with further analysis of data on the three most common histological subtypes (leiomyosarcoma [LMS], undifferentiated pleomorphic sarcoma [UPS], synovial sarcoma [SS]) in the cohort. RESULTS: Data of 552 adults (57.6% women, median age: 52 years) were analyzed. DCR and ORR were 43.1% and 30.8%, respectively. Median PFS was 6.7 months and OS was 13.8 months. For LMS, UPS and SS, median PFSs were 6.1, 5.9 and 7.53 months and median OSs were 15.03, 12.87 and 12.27 months, respectively. ECOG ≥ 2 was associated with poor PFS and OS. Liver metastasis was only a factor for progression. Second-line use of pazopanib (vs. front-line) was associated with better PFS, its use beyond third line predicted worse OS. Adverse events (AE) occurred in 82.7% of patients. Most common AEs were fatigue (58.3%) and anorexia (52.3%) which were graded as ≥ 3 in 8.2% and 7.4% of patients, respectively. CONCLUSION: Pazopanib is effective and well-tolerated in treatment of non-adipocytic metastatic STS. Its earlier use (at second-line), good performance status may result in better outcomes. Worldwide scientific collaborations are important to gain knowledge on rarer STS subtypes by conducting studies in larger patient populations.

Recurrent delayed immune-related pneumonitis after immune-checkpoint inhibitor therapy for advanced osteosarcoma.

Introduction: The case of a patient who developed recurrent delayed immune-related pneumonitis (checkpoint inhibitor pneumonitis [CIP]) after immune checkpoint inhibitor (ICI) therapy for advanced osteosarcoma treatment is presented. Case summary: A 25-year-old female patient with metastatic osteosarcoma was treated with atezolizumab. Grade 2 pneumonitis developed three times in the first two years. Treatment was discontinued after recovery from the last episode of pneumonitis, which was complicated with secondary spontaneous pneumothorax. 2 years after discontinuation of immunotherapy, the patient again developed CIP. Pneumonitis symptoms were regressed with oral steroid therapy during follow-up and a stable disease response continued. Conclusion: Immunotherapy can cause recurrent CIP at any time during the treatment period or after discontinuation of treatment.

Immune checkpoint inhibitors have been used in many types of cancer because they cause prolonged tumor responses. However, new side effects associated with these drugs have been identified. Pneumonia of the lung tissue may occur and recur during the use of these drugs or after their discontinuation. Patients with newly developing pulmonary symptoms during follow-up should be carefully monitored for this side effect.