悪性腫瘍の診断から治療まで : 喉頭癌について

Abstract

Intrinsic factors for carcinogenesis of the laryngeal cancer are character, sex, age and heredity, and extrinsic ones are tobacco, alcohol, occupation and previous radiation. The great majoirity of carcinoma of the larynx is squamous cell carcinoma. The glottic cancer originates in the stratified squamous epithelium of the vocal cord, while most of the supraglottic cancer originates in the squamous metaplasia of the stratified ciliated epithlium of the supraglottis. Histological growth pattern, stromal reaction and grade of malignancy are different between glottic and supraglottic cancers. System for diagnosis of carcinoma of the larynx is summarized as follows ; 1) history including Brinkman index, 2) indirect laryngoscopy, palpation of the neck and laryngofiberscopy, 3) cytology and histology, 4) laminagraphy and laryngography, 5) sonagram and stroboscopy, 6) CT scan, 7) Ga scintiscan and X-ray study including chest and upper GI, 8) physical examination, and 9) immunological test. Generally, true fixation of the vocal cord and cartilage destruction are the burden to curative radiotherapy for carcinoma of the larynx. Recently, destruction of the cartilage is able to be finely detected by CT scan. Treatment policy is generally accepted as follows ; 1) external radiotherapy is the treatment of choice in early lesion, 2) in patients with moderately advanced tumors, three different modalities such as preoperative radiotherapy, initial radiotherapy and initial surgery are offered by various authors, 3) for advanced lesions of T4 with or without nodal deposits, total laryngectomy with radical neck dissection gives the best chance for-long-term survival. Since the treatment failure depends on the volume factor for early glottic cancer and on the dose-time factor for moderately advanced lesion, it is necessary to improve the radiotherapy tehnique considering the present status of average department of radiotherapy in Japan. Based on the long-term study over 25 years at Osaka University Hospital and The Center for Adult Diseases Osaka, overall 10-year relative survival rate of carcinoma of the larynx is 73.8%. In the cases of glottic cancer, 10-year relative survial rates are 103.2% and 70.3% in stage I and IV, respectively. In the cases of supraglottic cancer, 10-year relative survival rates are 95.0% and 50.8% in stage I and IV, respectively.