C-Reactive Protein as a Biomarker of Radiation Therapy and Chemotherapy Toxicity Monitoring in Patients With Head and Neck Cancer

Abstract

C-reactive protein (CRP) is a serum protein elevated in a variety of illnesses, including cancer. Also some data exist that CRP level is correlated with acute mucositis in patients (pts) with head and neck cancer (HNC) treated with radiation therapy (RT) and significantly elevated when dose/fraction number is increased. The purpose of this study is to show how CRP behaves before and after HNC RT with or without chemotherapy. From 2010 to 2015, 401 pts (318 men and 83 women) with a mean age of 58 years (range 20-81) with oral cavity (5), nasopharynx (30), oropharynx (133), hypopharynx (47), larynx (180), or unknown primary (6) cancer were under treatment. Tumor stage was evaluated in all pts: T0-6, T1-60, T2-147, T3-119, T4-69, and N0-174, N1-52, N2-143, and N3-32. Four schedules of treatment have been used: RT alone (RTA, 178 pts), concurrent chemoradiation therapy (CRC, 93 pts), and induction chemotherapy (IC) followed by RTA (46 pts) or CRC (84 pts). CRP (normal level, <2.87mg/L) was measured as follows: before IC (if applied) or before RTA/CRC, every week during RTA/CRC, and, finally, 1 month after treatment. Total number of CRP measurements was 3622. Initial CRP level was normal in 56% of pts; in 44% it was elevated (median 6.05 mg/L) but not correlated with tumor advancement. After IC, normalization of CRP was observed in 73% of pts (median CRP decreased from 3.12 to 1.24 mg/L). During RT progressive, week by week up to week 6, elevation of CRP was observed for RTA and CRC with no difference between both treatments. However, evident impacts of initial CRP level and IC were noted; in patients who had abnormal initial CRP and/or IC, significantly higher CRP levels were observed over RTA and CRC. There was no correlation observed between CRP and total dose or overall volume of radiated tissue. CRP may be a useful laboratory parameter in monitoring of toxicity in HNC patients undergoing RTA and CRC. IC leads to significant reduction/normalization of CRP in the majority of patients, which may reflect an anti-inflammatory effect in tumor burden. Similar CRP levels in patients treated with RTA and CRC may suggest that tumor and normal tissue radiation sensitivity is an essential proinflammatory factor.