Ovarian Cancer

Ovarian cancer refers to cancer of the ovaries. Ovarian cancer often presents late due to the non-specific symptoms, resulting in a worse prognosis. More than 70% of patients with ovarian cancer present after it has spread beyond the pelvis.

 

Types of Ovarian Cancer

Epithelial Cell Tumours

Epithelial cell tumours (tumours arising from the epithelial cells of the ovary) are the most common type. Subtypes of epithelial cell tumours include:

  • Serous tumours (the most common)
  • Endometrioid carcinomas
  • Clear cell tumours
  • Mucinous tumours
  • Undifferentiated tumours

 

Dermoid Cysts / Germ Cell Tumours

These are benign ovarian tumours. They are teratomas, meaning they come from the germ cells. They may contain various tissue types, such as skin, teeth, hair and bone. They are particularly associated with ovarian torsion. Germ cell tumours may cause raised alpha-fetoprotein (α-FP) and human chorionic gonadotrophin (hCG).

 

Sex Cord-Stromal Tumours

These are rare tumours, that can be benign or malignant. They arise from the stroma (connective tissue) or sex cords (embryonic structures associated with the follicles). There are several types, including Sertoli–Leydig cell tumours and granulosa cell tumours.

 

Metastasis

Ovarian tumours may be due to metastasis from a cancer elsewhere. A Krukenberg tumour refers to a metastasis in the ovary, usually from a gastrointestinal tract cancer, particularly the stomach. Krukenberg tumours have characteristic “signet-ring” cells on histology, which look like signet rings on under a microscopy.

 

Risk factors

  • Age (peaks age 60)
  • BRCA1 and BRCA2 genes (consider the family history)
  • Increased number of ovulations
  • Obesity
  • Smoking
  • Recurrent use of clomifene

 

Factors that increase the number of ovulations, increase the risk of ovarian cancer. These include:

  • Early-onset of periods
  • Late menopause
  • No pregnancies

 

Protective Factors

Having a higher number of lifetime ovulations increases the risk of ovarian cancer. Factors that stop ovulation or reduce the number of lifetime ovulations, reduce the risk:

  • Combined contraceptive pill
  • Breastfeeding
  • Pregnancy

 

Presentation

Ovarian cancer can present with non-specific symptoms. In older women, keep the possibility of ovarian cancer in mind and have a low threshold for considering further investigations. Symptoms that may indicate ovarian cancer include:

  • Abdominal bloating
  • Early satiety (feeling full after eating)
  • Loss of appetite
  • Pelvic pain
  • Urinary symptoms (frequency / urgency)
  • Weight loss
  • Abdominal or pelvic mass
  • Ascites

An ovarian mass may press on the obturator nerve and cause referred hip or groin pain. The obturator nerve passes along the inside of the pelvic, lateral to the ovaries, where an ovarian mass can compress it.

 

Referral Criteria

The NICE “suspected cancer: recognition and referral” guidelines (2015) outlines the key referral criteria and red flags for ovarian cancer. They recommend either referring directly on a 2-week-wait urgent cancer referral or carrying out initial investigations in primary care depending on the presentation.

Refer directly on a 2-week-wait referral if a physical examination reveals:

  • Ascites
  • Pelvic mass (unless clearly due to fibroids)
  • Abdominal mass

 

Carry out further investigations before referral in women presenting with symptoms of possible ovarian cancer, starting with a CA125 blood test. This is particularly important in women over 50 years presenting with:

  • New symptoms of IBS / change in bowel habit
  • Abdominal bloating
  • Early satiety
  • Pelvic pain
  • Urinary frequency or urgency
  • Weight loss

 

Investigations

The initial investigations in primary or secondary care are:

  • CA125 blood test (>35 IU/mL is significant)
  • Pelvic ultrasound

 

The risk of malignancy index (RMI) estimates the risk of an ovarian mass being malignant, taking account of three things:

  • Menopausal status
  • Ultrasound findings
  • CA125 level

 

Further investigations in secondary care include:

  • CT scan to establish the diagnosis and stage the cancer
  • Histology (tissue sample) using a CT guided biopsy, laparoscopy or laparotomy
  • Paracentesis (ascitic tap) can be used to test the ascitic fluid for cancer cells

 

Women under 40 years with a complex ovarian mass require tumour markers for a possible germ cell tumour:

  • Alpha-fetoprotein (α-FP)
  • Human chorionic gonadotropin (HCG)

 

Causes of Raised CA125

CA125 is a tumour marker for epithelial cell ovarian cancer. It is not very specific, and there are many non-malignant causes of a raised CA125:

  • Endometriosis
  • Fibroids
  • Adenomyosis
  • Pelvic infection
  • Liver disease
  • Pregnancy

 

Staging

The International Federation of Gynaecology and Obstetrics (FIGO) staging system is used to stage ovarian cancer. A very simplified version of this staging system is:

  • Stage 1: Confined to the ovary
  • Stage 2: Spread past the ovary but inside the pelvis
  • Stage 3: Spread past the pelvis but inside the abdomen
  • Stage 4: Spread outside the abdomen (distant metastasis)

 

Management

Ovarian cancer will be managed by a specialist gynaecology oncology MDT. It usually involves a combination of surgery and chemotherapy.

 

Last updated July 2020
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