Carbon ion radiotherapy for malignant melanoma of female genital organs

e16548 Background: Malignant melanoma of the female genital organs is a very rare tumor and resistant to conventional photon radiotherapy. We report six cases of female genital malignant melanoma those were well controlled locally by carbon ion radiotherapy (CIRT). Methods: Between November 2004 and October 2008, six patients with unresectable female genital malignant melanoma were treated with CIRT. Age of the patients ranged from 55 to 80 years (median; 69 years). Four patients had previously untreated locally invasive tumors and other two had locally recurrent tumors after surgery and adjuvant chemotherapy. The tumor located in the vagina (4 patients), both the cervix and the vagina (1 patient), or both the vagina and the vulva (1 patient). Two patients had inguinal lymph node metastasis and two had distant metastases at CIRT. All patients received a total dose of 57.6 gray equivalent (GyE) in 16 fractions over 4 weeks of CIRT. Three patients received chemotherapy using dacarbazine, ACNU, and vincristine after CIRT. Results: The follow-up durations after CIRT were from 9 to 20 months (median; 13 months). No patient developed severe acute toxicity during CIRT. No late toxicity of greater Grade 2 was experienced, while Grade 1 proctitis was observed in a patient. All tumors completely responded to CIRT. No patient developed in-field recurrence. The four patients without distant metastasis were alive with no evidence of disease for 9–20 months after CIRT. The two patients with distant metastases died from metastatic disease 13 and 18 months after CIRT, respectively. Conclusions: CIRT achieved favorable local tumor control without developing severe acute and late toxicity in the treatment of unresectable malignant melanoma of the female genital organs. No significant financial relationships to disclose.