Advances in treating ovarian cancer
Dr Trudy Smith tells us more about how ovarian cancer is diagnosed and the new advances in treatment.
Ovarian cancer (OC) is the third most common cancer of the reproductive organs, following cervical and uterine cancer. It usually affects women between the ages of 50 and 70 and although possible, rarely affects women below age 40. If it does occur in younger patients, this may be as a result of a genetic predisposition to OC. Approximately 25% of OCs are part of a familial cancer syndrome which results from inherited changes in certain genes.
- Older age – As you age, your cells are unable to repair themselves and the risk of developing an overgrowth of cells increases.
- Age of first menstruation and menopause – Starting your menstrual cycle at an earlier age as well as starting menopause later increases the risk of developing OC.
- Never having a pregnancy and not taking contraception – There is an increased risk if you have more ovulatory periods. Taking combined oral contraceptives has been shown to decrease the risk of OC. Although, there is no firm conclusion as yet as to whether the induction of ovulation in infertility management has any effect on OC risk.
- Obesity – Being overweight predisposes women to many cancers including: breast, endometrial and ovarian cancer.
- Having breast cancer -The reproductive risk factors for both these cancers are similar, hence the close correlation. There may also be a hereditary family syndrome.
- Family history of ovarian, breast, or colorectal cancer – There are several familial cancer syndromes. The risk of having an inherited syndrome is higher, the more direct relatives you have with OC. This can come from both maternal and paternal sides of your family.
Hereditary breast and ovarian syndrome
This is an aberration in the BRCA1 and BRCA2 genes as well as other possibly undiscovered genetic mutations. The lifetime risk of developing OC if you have a BRCA1 gene is 35-70%, and if you have a BRCA 2 gene between 10-30% by age 70.
Additionally, these mutations may cause primary peritoneal and fallopian tube cancers. Thus, genetic screening has played an important role in cancer risk management. Understanding your genetics can also play an influential role in cancer treatment with drugs, such as poly (ADP-ribose) polymerase (PARP) inhibitors. These have shown to improve survival if used in women who have BRCA 1 or 2 mutations.
This gene aberration can be found solely in a tumour, a somatic BRCA, or it can be found in your blood, highlighting a genomic concern. In essence, it’s possible that the cancer itself can develop a problem with this gene without the person having an inherited genetic mutation.
This syndrome is where there are family lines of colon, uterine and ovarian cancer. Many different genes can cause this syndrome. Approximately 1% of OCs are caused by this genetic problem.
Diagnosing ovarian cancer
Unfortunately, the symptoms of OC are very vague and can include: bloating, feelings of fullness, and a distended stomach. Often, these are passed off as irritable bowel syndrome.
There are no accurate tests for screening. A vaginal ultrasound can show normal ovaries and has a low positive predictive value. The classic tumour marker, CA-125, is often asked for but this is an inaccurate test as it isn’t specific to OC. This marker can be elevated for other conditions, which don’t indicate cancer, such as fibroid uterus, endometriosis and it can even vary in a menstrual cycle. Several other tests have been tried with little success.
If there is an ovarian mass, this is characterised by its size, shape, projections and several other characteristics which then can give us a risk of malignancy index. This index will help the practitioner give some sort of indication as to whether the mass is malignant or not.
As practitioners, we tend to avoid doing a biopsy on ovarian masses as the tumour may be confined to the ovary and if we biopsy it, it will spill into the belly and change the staging. If the tumour is advanced, a biopsy can be done to make a diagnosis and then plan treatment accordingly.
New in treatment: PARP inhibitors
Surgery together with chemotherapy is the mainstay of treatment but a new targeted treatment has been introduced called a PARP inhibitor.
These targeted therapeutic drugs interfere with enzymes that help cancer cells repair and persist. Blocking these enzymes allows the cancer cells to die. PARP inhibitors are used to treat ovarian, fallopian tube and other cancers inconjunction with conventional chemotherapy and surgery.
MEET THE EXPERT – Dr Trudy Smith
Dr Trudy Smith is a gynaecology oncologist at Wits Donald Gordon Medical Centre and a senior lecturer at the University of Witwatersrand. She has a keen interest in teaching postgraduates and undergraduates.
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