Comparison Of Toxicity And Tumor Response In Early Glottic Cancer Treated With Conventionally Fractionated (Crt) Versus. Hypofractionated Radiation Therapy (Hrt): Retrospective Analysis Of A Single-Institution Experience

The optimal dose-fractionation schedule for early glottic cancer has been subject to debate. Schedules utilizing 2.25 Gy/fraction had evolved mainly on the basis of retrospective data. Prospective randomized data showing superiority of such fraction size when compared with 2 Gy/fraction were provided only from one trial published in 2006. Our objective was to analyze our own single institutional experience to address the benefit or risk of fraction sizes of 2.25 Gy vs 2 Gy. One hundred patients with biopsy-proven T1-T2 glottic squamous cell cancer were treated with RT at our institution between 2003 and 2013 and were analyzed retrospectively. The median age was 64 years (range, 31 - 94). Seventy-six had T1 tumors and 24 had T2. Forty-eight received 2 Gy daily (CRT Group) and 52 received 2.25 Gy daily (HRT Group). Median RT dose was 66 Gy (range, 54 - 70) for CRT and 63 Gy (range, 58.5 - 67.5) for HRT. Logistic regression, t-test, and log-rank test were used to compare the two groups and two-sided p-value was reported. Recurrence-free survival (RFS) was estimated using Kaplan-Meier method. The median follow-up was 28.8 months overall, with 54.7 months (range, 7.1 - 117.4) for CRT and 16.1 months (range, 5 - 64.7) for HRT, after excluding from local control analysis 9 patients with follow-up <3 months. CRT patients had less grade 2 dysphagia [odds ratio (OR) = 0.3, p = 0.014], grade ≥2 hoarseness [OR = 0.2, p = 0.001], grade ≥2 laryngeal mucositis [OR = 0.2, p<0.001], and required less frequent administration of opiate analgesics [OR = 0.3, p = 0.004] during treatment. The rates of grade ≥2 radiation dermatitis [OR = 0.7, p = 0.421], grade ≥2 laryngeal edema [OR = 0.8, p = 0.549], and weight loss (1.3% vs 2%, p = 0.655) during treatment were similar. Complete response was achieved in 91.7% in the CRT group vs 90.4% for HRT. RFS was comparable at 24 months [86.7% vs 86.6%, p = 0.988] and at 60 months [82.8% vs 78.8%, p = 0.655] in patients receiving CRT and HRT. P-value of log-rank test for RFS was 0.797. With exception of grade 2 dysphagia (p = 0.156), univariate analysis for the 76 T1 patients upheld the significance for all of the above findings, including complete response and RFS. Our retrospective data suggest that early glottic cancer treated with 2.25 Gy/fraction may result in higher incidence of grade ≥2 hoarseness, grade ≥2 laryngeal mucositis, and increased need of analgesics in comparison with 2 Gy fractions without improvement in complete response rate or recurrence-free survival.