41. The Phase I & II Clinical Study of Carbon Ion Therapy for Cancer of the Uterine Cervix

Takashi Nakano,M.0., Michiya Suzuki,M.D Atsuko Abe,M.0., Yoshiyuki Suzuki,M.0 Shinroku Morita,M.D., Junetsu Mizoe,M.0 Shinichiro Sato , PhD . , M . D Tadaaki Miyamoto,M.0., Tadashi Kamada,M.D Hirotoshi Kato,M.D., and Hirohiko Tsujii,M.0

Keywords: clinical trail, carbon ion beam, heavy ion therapy, cervical cancer, radiation therapy, prognosis, local control, radiation response

The phase I&II clinical study of carbon ion beam therapy was undertaken for 31 advanced cervical cancers of stages 3B and 4A from June 1995 to November 1997. The main purposes were to determine clinically taseful fraction dose without severe acute reaction of normal tissues and to assess tumor control dose levels achievable without significant normal tissue toxicity.

The treatment consisted of four fractions per week, 24 fractions over 6 weeks and was initiated with a fraction dose of 2.2 GyE which increased as 2.4 GyE, 2.6 GyE, 2.8 GyE, and 3.0 GyE. Consequently the total dose was initiated with 52.8 GyE, increasing up to 72.0 GyE by 4.8 GyE steps in dose escala tion fashion. Thirty patients with eligible advanced cervical cancers, i.e. 27 squamous cell carcinomas and three adenocarcinomas, were analyzed.

Acute response of normal tissues was less than photon treatment until fraction doses of 2.8 GyE and patients finished their treatment under comfortable conditions. Severe late complication occurred in two patients who received more than 67.2 GyE. The 2 year cumulative survival rate and local control rate of 27 patients with squamous cell carcinomas were 61.5 % and 59.3 %, respectively. According to stages, the 2-year survival rates of stages 3B and 4A patients were 54.4 %, and 75.0 %, respectively. The 2-year-local control rates of stages 3B and 4A patients were 52.6 %, and 75.0 %, respectively.

These results indicated that the disease control seemed to be relatively better for very advanced disease and dose escalation treatment. Local control was not significantly correlated with total dose and tumor volume. The present study, in spite of its small numbers and short observation period, suggested that adequate fraction dose for pelvis fields in 2.8-3.0 GyE and carbon ion beam therapy might be of advantage for advanced cervical cancer.