Hypofractionated radiotherapy for early stage glottic cancer: efficacy of 3.5 Gy per fraction

Abstract

Purpose: The purpose of this study was to evaluate the treatment outcomes and toxicity profile of patients with early glottic cancer who underwent hypofractionated radiation therapy (RT) with 3.5 Gy per fraction.Materials and Methods: A retrospective review was performed of the medical records of 35 patients with early stage (T1-2N0M0) glottic cancer who underwent definitive RT. The dose fractionation scheme was 59.5 Gy in 17 fractions. Posterior commissure was excluded from the clinical target volume (CTV) for 26 patients (74.3%) without glottic lesions close to this region. Results: With a median follow-up of 16.23 months (range, 6.82 to 67.15 months), no local, regional, or distant recurrence was reported. Acute hoarseness (65.7%), mucositis (68.6%), radiation dermatitis (60.0%) was frequent. One patient (2.9%) reported grade 3 acute toxicity (mucositis) and there was no grade 4–5 acute toxicity. There was no grade ≥3 late toxicities; however, grade 1 late intermittent hoarseness was frequent (45.7%). The receiver operative characteristic analysis revealed that mean hypopharyngeal dose was predictive for acute grade ≥2 mucositis (area under the curve=0.9314; 95% confidence interval, 0.8524–1). The optimal threshold of mean hypopharyngeal dose for occurrence of acute grade ≥2 mucositis was 26.31 Gy, with a specificity and sensitivity of 83.3% and 88.2%, respectively.Conclusion: Hypofractionated RT with fraction size of 3.5 Gy for early glottic cancer is effective. The hypopharyngeal mean dose could predict the occurrence of grade ≥2 acute mucositis. The posterior commissure can be safely excluded from the CTV.

Hypofractionated radiation therapy for head and neck cancers in the era of intensity-modulated radiation therapy

“…HFRT with single-fraction doses greater than 2.4 Gy is still experimentally used for H&N cancers, with the exception of early-stage glottic cancer, but its adoption is limited by a lack of high-quality evidence and concerns about potential long-term late toxicity. In early glottic cancer, several published studies have demonstrated the effectiveness of HFRT at doses above 2.4 Gy [9][10][11]. Clinical trials applying stereotactic RT to this cancer are also underway; however, concerns regarding toxicity persist [12][13][14].…”

"Radical Radiotherapy for Early-Stage Carcinoma of the Glottis. Should We Switch to Hypofractionation?"

“…In the last 10 years the technical developments have remarkably increased the precision in RT treatment planning and RT delivery (Intensity Modulated RT-IMRT, Image Guided RT-IGRT, Tomotherapy) and have allowed radiation oncologists to use another type of altered fractionation called "hypofractiona¬tion" which employs daily dose (per fraction) of higher than 2 Gy, for instance 2.2-2.75 Gy or even higher [16,17]. All clinical trials and retrospective studies agree that tumor control is at least equivalent to standard fractionation and the post-radiation effects are rather reduced [18][19][20][21][22], let alone the favorable consequences of the lower number of RT fractions (see previous paragraph).…”