Clinical investigation: head and neck
Radiation therapy in T1–T2 glottic carcinoma: influence of various treatment parameters on local control/complications

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Abstract

Purpose: To evaluate the influence of various treatment parameters on local control as well as complications in T1 and T2 glottic carcinomas.

Methods and Materials: Between 1975 and 1989, 676 patients with early glottic carcinoma (460 T1 and 216 T2) received curative radiation with three different treatment regimens, as follows: Regimen 1—50 Gy/15 Fr/3 weeks (3.33 Gy/daily) for 192 patients; Regimen 2—60–62.5 Gy/24–25 Fr/5 weeks (2.5 Gy/daily) for 352 patients; and Regimen 3—55–60 Gy/25–30 Fr/5–6 weeks (2–2.25 Gy/daily) for 132 patients.

Results: The local control at 10 years was 82% and 57% for T1 and T2 lesions respectively (p = 0.0). For the T1N0M0 group, field size had significant impact on local control with both univariate (p = 0.05) and multivariate (p = 0.03) analysis. For T2N0M0, group field size (p = 0.03) as well as registration year (p = 0.016) were significant in univariate analysis whereas only field size remained significant on multivariate analysis. Persistent radiation edema was noted in 146 (22%) patients and was significantly worse with larger field size (p = 0.000) but not related to different treatment regimens.

Conclusion: The shorter fractionation schedule had comparable local control, without increased complications in comparison to the protracted schedule and is best suited for a busy department.

Introduction

Early-stage invasive squamous cell carcinoma of the vocal cord can be effectively managed by radiation therapy or surgery. The benefits of radiotherapy in terms of preservation of laryngeal structure and function have been well documented and radiation therapy is the treatment of choice in most centers (1). For T1 lesions, 5-year local control rates of 85%–95% have been reported and for patients with T2 lesions, local control with radiation therapy alone can be achieved in 75% to 85% of cases 2, 3, 4, 5. The influence of various factors such as T category, impaired cord mobility, and gender on local control after definitive therapy has been well documented. Despite the high success rate in controlling early-stage glottic carcinomas, the importance of fraction size and total dose is not well defined (6). At the Tata Memorial Hospital, treatment of early-stage glottic carcinoma has evolved over the last two decades from prescription of small daily fractions and protracted course to larger daily fractions and shorter overall times. The purpose of this study was to review our experience in the treatment of T1 and T2 glottic carcinoma during the period 1975–1989 and to examine the influence of various treatment parameters on local control and complications.

Section snippets

Patient characteristics

From January 1975 to December 1989, 676 patients with T1 or T2 squamous cell carcinoma of true vocal cords were irradiated with curative intent at the Tata Memorial Hospital. There were 640 male and 36 female patients with a male:female ratio of 18:1. Age ranged from 22 to 86 years (median 57 years) with 343 patients ≤57 and 333 patients >57 years. The median follow-up for alive patients was 45 months.

Staging

Pretreatment evaluation included physical examination, complete blood count, chest X-ray,

Pattern of treatment failure

Of the 676 patients (460 T1 and 216 T2) treated with radiation, local failure occurred in 104 patients (54 T1 and 50 T2). The median time to local recurrence was 35 months. Of 104 patients, 97 (93%) local relapses occurred within the first 5 years.

Table 3 shows the pattern of treatment failure. The first site of relapse included: vocal cords only in 97 patients, regional nodes only in 10 patients, and vocal cord plus regional nodes in 7 patients. Three patients developed distant metastasis.

Discussion

Radiation therapy for early laryngeal cancers offers an excellent probability of cure. The dual objective of treatment—controlling the malignant tumor and preserving a functionally useful voice—is best optimized by the use of radiotherapy in early glottic tumors. Although surgery can undoubtedly offer equally good results, it is best reserved in the event of radiation failures, with patients still given a second chance of cure (10).

Stalpers et al. (11) in a review of 26 articles from 1973–1985

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