Clinical benefit of cetuximab and prognostic value of cetuximab-related skin toxicity in metastatic colorectal cancer: a single institution analysis

Purpose: To evaluate the clinical benefits of cetuximab (CTX) and the prognostic value of CTX-related skin toxicity in metastatic colorectal cancer (mCRC) patients. Methods: Sixty patients were tested for KRAS mutation at the Department of Oncology, Clinical Centre Nis. We assessed 34 wild-type KRAS mCRC patients treated with CTX. All of them were refractory to prior fluoropyrimidine, oxaliplatin and irinotecan-based regimens. The maximum grade skin toxicity according to treatment cycle was analyzed. Skin toxicity was grouped into clinically non-relevant skin toxicity (grade 0-1: Group 1) and clinically relevant skin toxicity (grade 2-4: Group 2). Results: Ten out of 33 patients (30.30%) achieved partial response (PR). Eight additional patients (24.24%) showed stable disease (SD), whereas 15 (45.45%) had disease progression (PD). No patient achieved complete response (CR). Overall response rate (ORR) was 30.30%, whereas the disease control rate (DCR) was 54.54%.The median progression free survival (PFS) was 14 weeks. Some degree of skin toxicity was observed in 79.41% (27/34) of the patients. Clinically non-relevant skin toxicity was observed in 50% (17/34), and clinically relevant in 50 % (17/34) of the patients. Grade 4 skin toxicity was documented in 1 patient. The mean PFS in Group 1 was 12.65 +/- 5.59 weeks and in Group 2 22.82 +/- 12.16 (p < 0.05). The results showed that grade 2-4 skin toxicity was associated with significantly better response to treatment than skin toxicity grade 0-1, with regard to ORR (80.00 vs 20.00%; p < 0.05) and DCR (66.66 vs 33.33%; p < 0.05). Conclusion: Cetuximab has clinical benefit when given alone or in combination with irinotecan in patients with irinotecan-refractory CRC. Skin toxicity was one of the predictors of response and it was in line with what was expected.