Validity of colour and pulsed Doppler US and tumour marker CA 125 in differentiation between benign and malignant ovarian masses.

BACKGROUND

Colour and pulsed Doppler flow imaging have been proposed as methods that may be useful in differentiating benign from malignant ovarian masses. It has been hypothesised that the detection of neovascularisation with abnormal, low-resistance blood flow peculiar to malignant tumours is possible, being characterised by angle-independent Doppler indices--PI and RI. The initial studies reported cut-off values of 1.0 for PI and 0.4 or 0.7 for RI, with values below the cut-off suggestive of malignancy. Tumour marker CA 125 SC was found to be elevated in 80-85% of patients with serous epithelial ovarian cancer (90% of all ovarian cancers) and in a lower percentage in other ovarian cancers, with levels over 35 U/ml suggestive of malignancy. In our study we wanted to determine whether colour and pulsed Doppler US and CA 125 SC could be used to differentiate benign from malignant ovarian masses and whether, by combining the methods, the results could even be improved.

METHODS

Ovarian masses identified with sonography in 71 patients aged 35 years or more, were confirmed at surgery (n = 61) or endoscopy (n = 4) or followed up to resolution with US (n = 6). Colour and pulsed Doppler US were used to identify intratumoral areas of vascularisation and to calculate the lowest PI and RI for each ovarian mass. CA 125 SC were measured.

RESULTS

In 16 of 18 ovarian malignancies and 28 of 53 benign masses, areas of intratumoral vascularisation (colour flow) were detected with colour Doppler US (p = 0.002). Mean RI was lower in malignant than in benign masses (p = 0.198), as was PI (p = 0.248). Index values displayed considerable overlap between malignant and benign lesions and the differences were not significant. Mean CA 125 SC was higher in malignant than in benign masses (p = < 0.0001). For cut-off at 35 U/ml, SE, SP, PPV and NPV for identification of ovarian cancer were 83%, 74%, 79% and 75% respectively. Either CA 125 SC > 35 U/ml or intratumoral colour Doppler signal was detected in all 18 patients with ovarian cancer, but neither of them was detected in 25 patients all of whom had benign tumours. Thus, combining the two methods, SE, SP, PPV and NPV for ovarian cancer were: 100%, 47%, 32% and 100% respectively.

CONCLUSIONS

RI and PI values cannot be used to differentiate between benign and malignant ovarian tumours in women over 34 years of age. The determination of CA 125 serum level is useful in identification of ovarian cancer in women over 35 years of age. CA 125 SC under 35 U/ml together with the lack of detectable colour flow in the tumour, can reliably exclude ovarian malignancy in women over 35 years of age (NPV = 100%).