Adjuvant radiotherapy after transoral microlasersurgery for advanced primary squamous cell carcinoma of the head and neck

Abstract

We are presenting a retrospective analysis which is the first publication worldwide, focusing on adjuvant radiotherapy after laser surgery for advanced head and neck cancer based on a major case load. The treatment outcome is presented for a total of 208 patients treated at a single institution. The main advantage of laser surgery is the maintenance of organ function. In term of local control, survival, and quality of life the study compares favourably with the published reports on multimodal treatment in advanced head and neck cancer. Evaluation of risk factors revealed tumour stage, hemoglobin concentration at initiation of treatment, and the technique of adjuvant radiotherapy as major prognostic factors for therapeutic outcome. Between 1987 and 2000, 208 patients with advanced SCC of the head and neck were treated at the university of Goettingen (Germany), with postoperative RT following surgical CO2 laser-resection. Primary sites included oral cavity, 38; oropharynx, 88; larynx, 36; hypopharynx, 46. Disease stages were as follows: St. III, 40 patients, St. IV, 168 patients. The postoperative nodal stage was: pN0, 37 patients; pN1, 35 patients; pN2, 117 patients; and pN3, 19 patients. The radiotherapy protocol changed over time at our institution. Before 1994, the treatment A consisted of two fractions per day (2x 2.1 Gy), preceded by a dose of 50 mg/m2 carboplatinum i.v. daily. A total radiation dose of 56.70 Gy was applied to the neck and the primary tumour over 6 weeks as a split course regimen with a brake of 2 weeks. After 1994, treatment B consisted of a conventional radiotherapy (50 Gy + 10 Gy Boost) delivered in 30 treatment fractions of 2.0 Gy. Follow-up: All patients were examined every 6 months during the first 3 years after therapy, and every year after this period. They underwent clinical ENT-examination including magnifying laryngososcopy, ultrasound, and/or a computed tomography of the head and neck region if indicated. Statistics: Survival and local-regional control probabilities were calculated from the day of surgery. Disease Free Survival (DFS) was defined as the absence of recurrent disease above the clavicles and the absence of distant metastases. The Kaplan-Meier product-limit method was used to determine survival and the time to local failure. The log rank method was used to test for statistical significance. Multivariate analyses were estimated by means of the Cox proportional hazards model. Follow-up data were available on all patients. Each of them was followed until death for those who died or until December 2001 for those who were alive. The median follow-up period was 75 months (range 31 to 137 months). The Disease Specific Survival (DSS) and the Locoregional Control (LRC) were estimated with the Kaplan Meier curves. Patients had 5-year locoregional control (LRC) and diseases specific survival (DSS) rates of 62.5 %, and 45 %, respectively. The 5-year DSS was 66 % and 38 % for the stage III and IV, respectively (p = 0.006). Patients treated with a hemoglobin level superior or equal to 13.5 g/dl before radiotherapy had a 5-year DSS of 48.5% as compared with 37 % for patients treated with a hemoglobin level inferior to 13.5 g/dl (p = 0.01). The largest difference was found between the patients who received treatment B and who had a hemoglobin level superior or equal to 13.5 g/dl before radiotherapy and the patients who received treatment A who had a hemoglobin level inferior to 13.5 g/dl. In the first group the 5-year DSS was 54% compared with 38% in the second group (p = 0.002). In this series of patients with advanced head and neck tumours transoral laser surgery in combination with adjuvant radiotherapy resulted in locoregional control and DSS rates similar to those reported for radical surgery followed by radiotherapy. Laser surgery apparently leaves patients in a better clinical condition with higher hemoglobin levels and reduced surgical trauma, which is both likely enhancing the efficacy of postoperative radiotherapy