PURPOSE: The aim was to evaluate pretreatment lymph node size, irradiation dose, and failure patterns. METHODS: Pretreatment PET and CT were performed in 208 patients. Lymph nodes were scored as either positive or negative by PET and lymph node size was measured by CT. Lymph node irradiation dose and sites of failure were recorded. RESULTS: The mean pelvic lymph node doses were: PET negative nodes, < or =1 cm, 66.8 Gy, and 0/76 failures; PET positive nodes, < or =1 cm, 66.8 Gy, and 3/89 failures; 1.1-< or =2 cm, 66.9 Gy, and 0/21 failures; 2.1-< or =3 cm, 69.4 Gy, and 2/15 failures; and 3.1 to < or =4 cm, 74.1 Gy, and 0/5 failures. The mean paraaortic lymph node dose was 43.3 Gy and there were no paraaortic failures for 24 patients with PET positive < or =1 cm nodes, 0/5 failures for 1.1 to < or =2 cm, and 0/4 failures for 2.1 to < or =3 cm. The most common site of failure was distant metastases. CONCLUSIONS: The irradiation doses given in this study were adequate to control most lymph node metastases. Positive lymph nodes of any size at diagnosis were the most significant predictor for developing distant metastases.
PURPOSE: The aim was to evaluate pretreatment lymph node size, irradiation dose, and failure patterns. METHODS: Pretreatment PET and CT were performed in 208 patients. Lymph nodes were scored as either positive or negative by PET and lymph node size was measured by CT. Lymph node irradiation dose and sites of failure were recorded. RESULTS: The mean pelvic lymph node doses were: PET negative nodes, < or =1 cm, 66.8 Gy, and 0/76 failures; PET positive nodes, < or =1 cm, 66.8 Gy, and 3/89 failures; 1.1-< or =2 cm, 66.9 Gy, and 0/21 failures; 2.1-< or =3 cm, 69.4 Gy, and 2/15 failures; and 3.1 to < or =4 cm, 74.1 Gy, and 0/5 failures. The mean paraaortic lymph node dose was 43.3 Gy and there were no paraaortic failures for 24 patients with PET positive < or =1 cm nodes, 0/5 failures for 1.1 to < or =2 cm, and 0/4 failures for 2.1 to < or =3 cm. The most common site of failure was distant metastases. CONCLUSIONS: The irradiation doses given in this study were adequate to control most lymph node metastases. Positive lymph nodes of any size at diagnosis were the most significant predictor for developing distant metastases.