A careful physical examination of the woman is essential and should include abdominal and vaginal examination, and examination to determine the presence or absence of local lymphadenopathy. Although clinical examination has poor sensitivity in the detection of ovarian masses, its importance lies in the evaluation of mass tenderness, mobility, nodularity and ascites.
In the acute presentation with pain the diagnosis of accident to the ovarian cyst should be considered (torsion, rupture, haemorrhage).
A pelvic ultrasound is the single most effective way of evaluating a pelvic mass with transvaginal ultrasonography being preferable due to its increased sensitivity over transabdominal ultrasound. Routine use of CT or MRI is not indicated but where clinical or ultrasound suspicion exists, refer to Guidelines for Imaging of Gynaecological Malignancy (West of Scotland Cancer Network Guideline). CT of the abdomen and pelvis should be performed for masses with RMI >200 or in those with RMI <200 where clinical or ultrasound suspicion exists. MRI pelvis / lower abdomen should be performed in those with a complex mass which is difficult to characterise clinically or on ultrasound, or in young women (<30yrs) with suspected malignant tumour or a complex pelvic mass.
- CA125 – a serum CA125 assay does not need to be undertaken in all premenopausal women when an ultrasonographic diagnosis of a simple ovarian cyst has been made, but should be performed in all other circumstances. However it must be recognised that it is unreliable in determining whether ovarian lesions are benign or malignant as CA125 is also raised in conditions such as fibroids, endometriosis, adenomyosis and pelvic infection. Note also that CA125 is primarily a marker for epithelial ovarian tumours but is only elevated in around 50% of early stage disease.
- LDH, αFP and hCG should be measured in all women under the age of 40 with a complex ovarian mass to exclude germ cell tumours.
- Calculate RMI – see below.
Calculation of the RMI
RMI combines three presurgical features: serum CA125 (CA125); menopausal status (M); and ultrasound score (U).
The RMI is a product of the ultrasound scan score, the menopausal status and the serum CA125 level (IU/ml) as follows: RMI = U x M x CA125
- The ultrasound result is scored 1 point for each of the following characteristics: multilocular cysts, solid areas, metastases, ascites and bilateral lesions. U = 0 (for an ultrasound score of 0), U=1 (for an ultrasound score of 1, U=3 (for an ultrasound score of 2-5).
- The menopausal status is scored as 1=premenopausal and 3=postmenopausal.
- Postmenopausal can be defined as women who have not had a period for more than one year or women over the age of 50 who have had a hysterectomy.
- Serum CA125 is measured in IU/ml and can vary between zero to hundreds or even thousands of units.