Background: The crucial role of angiogenesis in tumor behaviour has been studied extensively in vitro. The authors assessed the in vivo angiogenesis in ovarian neoplasms by color Doppler ultrasound and waveform analysis.
Methods: The intratumor artery resistance index (RI) of 222 ovarian neoplasms referred for color Doppler ultrasound evaluation was measured, and the corresponding histopathologic diagnosis was recorded.
Results: Satisfactory intratumor artery waveforms were obtained at an average of 1.12 sites in 44.7% (68 of 152) of benign tumors and at 6.28 sites in 97.1% (68 of 70) of the malignant group. Great heterogeneity in RI values existed. The RI of the intratumor artery in the benign group during the follicular phase (mean, 0.678) was significantly higher (P < 0.001) than that of the luteal phase (mean, 0.414), epithelial ovarian carcinoma (n = 34; mean, 0.402), malignant germ cell tumor (n = 6; mean, 0.413), malignancy metastasized to the ovary (n = 18; mean, 0.357), and other rare malignancies (n = 4; mean, 0.435). The RI of primary ovarian malignancy (n = 41; mean, 0.411) was significantly higher than that of malignancy metastasized to the ovary (P < 0.05). The RI values of epithelium-originated neoplasms showed a significant incremental decrease from benign tumors (n = 48; mean, 0.695) toward borderline malignancy (n = 6; mean, 0.535; P < 0.01), early-stage ovarian carcinoma (n = 10; mean, 0.485; P < 0.01), and, finally, to advanced-stage ovarian malignancies (n = 29; mean, 0.398; P < 0.05).
Conclusions: Angiogenesis is a common phenomenon in malignant ovarian neoplasms, but the intensity of neovascularization may depend on individual tumor characteristics. The authors documented the incremental decrease of the resistance index in ovarian neoplasms, which may reflect the increase in angiogenesis intensity as an indication of malignant potential.