Amifostine in simultaneous radiochemotherapy of advanced head and neck cancer

Abstract

The authors discuss the results of 3 studies of their group reflecting the possible role of amifostine in simultaneous radiochemotherapy (RCT) of advanced head and neck cancer. In a controlled phase II trial (1995 through 1996), 39 patients were included in this pilot investigation. A control group (n = 14) received simultaneous RCT of the head and neck region with an irradiation dose of 60 Gy and 2 cycles of carboplatin (700 mg/m(2) cumulative dose). Twenty-five patients received the same basic therapy and an additional 500-mg dose of amifostine before each chemotherapy. Amifostine was administered less than 45 minutes before the end of radiotherapy. The authors observed a dramatic reduction of typical radiotherapy-associated toxicities (mucositis, xerostomia, loss of taste, dysphagia). The hematologic side effects (leukocytopenia, anemia, thrombocytopenia) also were decreased significantly. The overall survival rate and locoregional control of both groups were comparable after 12 months. In a controlled intensification trial (1997 through 1999), the authors included 76 consecutive patients (69 men, 7 women) with pharyngeal cancer (oropharynx, n = 33; hypopharynx, n = 43). The tumors were characterized as unresectable and locally advanced without distant metastasis. All patients received a conventional radiotherapy (2-Gy single dose, daily fractionation) up to doses of 60 Gy and an additional 10 Gy as a boost in the tumor-infiltrated region. A dose of carboplatin, 70 mg/m(2), was given to a group of 45 patients on days 1 through 5 and 29 through 33 of radiotherapy (RCT arm). The resulting cumulative dose was 700 mg/m(2). A group of 31 patients (RCTintens arm) received the same dose of carboplatin on days 1 through 5, 22 through 26, and 43 through 47 or 1 through 5, 15 through 19, 29 through 33, and 43 through 47 of radiotherapy (cumulative dose 1.05 to 1.40 mg/m(2)). All patients received 500 mg of amifostine before each carboplatin administration. If the tumor volume was less than 20 cm(3), we observed an increased 1-year overall survival rate (91% v 71%) and time to progression (17 months v 10 months). If the tumor volume was greater than 20 cm(3), we observed comparable treatment results in both groups (1-year survival rate, 60% v 61%; time to progression, 13 months v 12 months). In a long-term follow-up investigation (1999 through 2000), 531 patients (89 women, 442 men) were analyzed according to their toxicities during regular follow-up investigations at our outpatient facility. All patients were treated by surgery or radio(chemo)therapy because of an advanced head and neck cancer. A total of 218 of 531 patients received the antineoplastic therapy without cytoprotection. An additional 313 patients received their RCT combined with amifostine administration before administration of the radiosensitizer. A significant influence of cytoprotection was registered in the following toxicities: xerostomia, fibrosis, loss of taste, and dysphagia. No impact was seen on the development of interstitial lymph edema and esophageal stenosis. Amifostine could be integrated in simultaneous radiochemotherapy of advanced head and neck cancer patients. The authors favor the administration of amifostine before chemotherapeutics alone. Selective cytoprotection could decrease the main acute toxicities (mucositis, xerostomia, dysphagia) as well as late side effects (xerostomia, loss of taste, fibrosis) of this form of combined treatment. The enhanced therapeutic index may be changed into a prognostic benefit for selected patients with unresectable tumors, if the volume is smaller than 20 cm(3).