A11. Ovarian cancer; classification, symptoms and diagnosis

Page created on June 7, 2021. Last updated on May 27, 2022 at 07:59

Definition and epidemiology

Ovarian cancer is the second most common gynaecological cancer (after endometrial), but the most common cause of gynaecological cancer death due to its poor prognosis. It has no early symptoms, it has potential to grow very large, and it has aggressive behaviour. There is no effective screening for it in the general population.

It is mostly a disease of postmenopausal women in the 55 – 65 age group.

The 5-year survival is 30 – 35%. The only real opportunity for survival is early diagnosis with complete surgical excision.

Etiology

Risk factors include:

• Old age
• BRCA1/BRCA2 mutation
• Family history
• Early menarche
• Late menopause
• Lynch syndrome

Protective factors include:

• Oral contraceptive pills
• Multiparity
• Breastfeeding

High oestrogen exposure is involved in the pathogenesis, which explains many of the risk and protective factors.

Classification

We can distinguish multiple histological types of ovarian cancer:

• Epithelial ovarian carcinoma – arise from ovarian surface epithelium
  • Serous type
  • Endometrioid type
  • Clear cell type
  • Mucinous type
  • Brenner tumour
• Germ cell tumours
  • Dysgerminoma
  • Teratoma
• Sex cord-stromal tumours
• Krukenberg tumour
  • Bilateral ovarian metastatic spread from gastric cancer

The epithelial type is the most common, accounting for 90%.

The FIGO classification is used for staging. As it’s not mentioned in the topic name, I assume we don’t need to know it.

Clinical features

Ovarian cancer is characteristically asymptomatic until the late stages, which is part of the reason for the poor prognosis.

When symptoms do appear, these are the most common:

• Abdominal enlargement (due to ascites)
• Symptoms of pressure on surrounding organs
  • Dysuria
  • Constipation
  • UTI
• Symptoms relating to complications of the tumour (usually acute)
  • Torsion – acute pain and vomiting
  • Rupture – generalised abdominal pain
  • Haemorrhage – abdominal pain and haemorrhagic shock

Diagnosis and evaluation

Physical examination should be performed for an adnexal mass as well as inguinal and cervical lymphadenopathy. Ultrasound of the adnexal mass can reveal features suspicious for malignancy (solid mass, irregularity, papillary structures, etc.) and ascites. Chest, abdominal, and pelvic CT or MRI are used to look for ascites and disease spread.

CA125 is a tumour marker for ovarian tumours. Its specificity is low in premenopausal women but high in postmenopausal. It should be routinely measured in postmenopausal women with adnexal masses, and, if elevated, should raise suspicion of malignancy. There are some other tumour markers which may be elevated in ovarian cancer. These are mainly used for follow-up rather than for diagnosis:

• HE4
• β-hCG
• AFP

Multiple models exist to assess the risk of ovarian malignancy based on ultrasound findings, CA125 level, and menopausal status. RMI (Risk of Malignancy Index) is the prototypic model, but this is old and is probably not as good as more modern models like the SRMP and ADNEX models. In any case, a RMI score > 200 suggests that the tumour is most likely malignant.

The definite diagnosis of ovarian cancer, as well as determination of its histological type, requires histology. Biopsy causes tumour seeding and is not performed. All cases of suspected ovarian cancer undergo complete surgical staging, involving total hysterectomy with bilateral salpingo-oophorectomy with pelvic and paraaortic lymph node dissection and omentectomy. Peritoneal cytology is also acquired by peritoneal washing. Only after histological evaluation of these samples can the diagnosis be made.

Screening

As already stated, there is no screening for it in the general population. However, we do screen people who have hereditary ovarian cancer or hereditary breast cancer. In these people, we can use serum markers, ultrasound, and frequent pelvic examination to screen them.

In high-risk patients (BRCA, Lynch syndrome), we can do prophylactic bilateral salpingo-oophorectomy after the age of 35.