A 66-year-old woman presents to the GP with six months of increased urinary frequency, ongoing lower abdominal discomfort, early satiety, and persistent mild abdominal distention. She was diagnosed with irritable bowel syndrome (IBS) six months ago after an unremarkable colonoscopy to investigate alternating constipation/diarrhoea

She is otherwise fit and well and her full blood count, renal profile, and liver function tests are normal.

Abdominal examination reveals a soft and non-tender abdomen, mildly distended, with no palpable masses. PR exam reveals soft stool in the rectum and no palpable masses.

Urine dip is clear

What is the most appropriate next investigation for this patient?

Options:
explanation: Any woman (especially if 50 or over) presenting with persistent abdominal distention (or "bloating"), early satiety/loss of appetite, pelvic/abdominal pain, or increased urinary urgency/frequency should warrant investigation for ovarian malignancy. Unfortunately most women with ovarian cancer present late with advanced disease and so a low grade of suspicion is required to pick up on subtle symptoms. Beware of the diagnosis of IBS in middle-age and elderly patients; it rarely presents for the first time in people in these age groups and is a diagnosis of exclusion. Serum CA-125 is a tumour marker for ovarian cancer and is the _first_ test you would order in this scenario, as well as routine bloods. If CA-125 is raised, an ultrasound of the abdomen and pelvis should be arranged. If the ultrasound shows suspected ovarian malignancy, a risk of malignancy index (RMI Score) should be calculated. If RMI score is 250 or greater, they should be referred to a specialist multidisciplinary team.

In women under 40 with suspected ovarian cancer, you should also measure levels of alpha fetoprotein (AFP) and beta human chorionic gonadotrophin (beta-hCG) to screen for germ cell ovarian tumours
name: CA-125
label: a
answer: yes
explanation: This is another sensible option as it is a good screening tool for abdominal and thoracic malignancies. Again, this patient's symptoms would warrant initial investigations with bloods, tumour markers, and likely subsequent ultrasound abdomen pelvis prior to full cross-sectional imaging. The question asks for the most appropriate _next_ investigation and we must start with simple investigations before exposing this patient to potentially unnecessary radiation. If the patient's CA-125 were raised and the ultrasound showed signs of malignancy, staging CT chest abdomen pelvis will likely be required to assess for metastases and guide management
name: CT chest abdomen pelvis
label: c
answer: no
explanation: This would be part of the investigations for a patient presenting with symptoms concerning of urological malignancy, particularly of urethral/bladder origin. This patient has a negative urine dip without haematuria and the history does not suggest any additional urological history. The history is more suggestive of other intraabdominal malignancy, particularly ovarian, and so other investigations would be conducted first
name: Flexible cystoscopy
label: d
answer: no
explanation: An ultrasound abdomen and pelvis will form a crucial part of the diagnosis of ovarian malignancy, although the question asks for the most appropriate _next_ investigation. If CA-125 was negative, you may consider alternative investigations such as CT chest abdomen pelvis for possible intra-abdominal malignancy, CT Urogram for urological malignancy, or ordering further tumour markers and bloods for more rare causes of this patient's symptoms
name: Ultrasound abdomen and pelvis
label: b
answer: no
explanation: Bloods and tumour markers would be the _next_ most appropriate investigation followed by abdominal ultrasound. TVUS is more sensitive than transabdominal ultrasound for characterising gynaecological malignancies
name: Transvaginal ultrasound (TVUS)
label: e
answer: no

Correct answer: a


Learning point: In women over 50, ongoing abdominal distention and urinary symptoms require evaluation for ovarian cancer, initially with serum CA-125 testing.