Dose-escalation study of carbon ion radiotherapy for locally advanced squamous cell carcinoma of the uterine cervix (9902).

OBJECTIVE

The authors performed phase I/II clinical trial to evaluate the toxicity and efficacy of carbon ion radiotherapy (C-ion RT) for locally advanced squamous cell carcinoma of the uterine cervix.

METHODS

Between April 2000 and January 2006, 22 patients for Protocol 9902 were treated with C-ion RT. The number of patients with stage IIB, IIIB, and IVA diseases was 1, 18, and 3, respectively. All patients had bulky tumors measuring 4.0-12.0 cm (median 6.2 cm). The whole pelvic dose was fixed at 39.0 GyE for 13 fractions, and additional 15.0 GyE for 5 fractions was given to the gross tumor volume (GTV) and surrounding tissues. With regard to local boost, a dose-escalation study was planned for 2 fractions to GTV. Total dose to the cervical tumor was 64.0-72.0 GyE for 20 fractions.

RESULTS

All patients completed the scheduled therapy and no patient developed Grade 2 or higher acute toxicity. There was no Grade 3 or higher late complications at each dose. The 5-year overall survival rate and local control rate were 50.0% and 68.2%, respectively. Seven out of the 16 patients who received 64.0-68.0 GyE developed local recurrences, but all patients who received 72.0 GyE maintained local control.

CONCLUSIONS

There were no severe acute or late complications in this trial. C-ion RT has the potential to improve the treatment for locally advanced bulky cervical cancer by applying a total dose of 72.0 GyE, with the results lending incentive to further investigations to confirm the therapeutic efficacy.