Gynaecological cancers are cancers that originate in the female reproductive system. They arise as a result of the uncontrolled and abnormal growth of cells found in the organs of the female reproductive system.
The types of cancers that arise in the female reproductive system are categorised based on the organ and the cell type from where it begins.
There are 3 main cell types that make up the ovaries. These cells are the epithelial cells (cells that cover the outer surface of the ovary), germ cells (cells that produce the ova) and structural tissue cells (also produce female hormones). Tumours can arise from any of these cells.
- Epithelial tumours – 85-90% of ovarian cancers develop from epithelial tumours. These are called epithelial carcinomas. There are further subtypes of epithelial carcinomas based on their features
- Stromal tumours – malignant tumours that involve the hormone-producing cells. Usually found at an early stage and have a good outlook
- Germ cell tumours – cancerous tumours are relatively rare, but may be life threatening. There are subtypes of germ cell tumours including teratomas
Endometrial cancer (cancer of the uterus/womb)
The uterus is comprised of 3 layers, one of them being the endometrium, which is the cells of the inner lining of the uterus. Endometrial carcinomas are categorised based on the cell type the cancer develops from. Cancers of the endometrium include:
- Uterine carcinosarcomas
- Squamous cell carcinoma
- Small cell carcinoma
- Transitional carcinoma
- Serous carcinoma
Cervical cancer is the 10 most common cancer in Singaporean women. The cervix is made up of 2 parts, and covered with 2 different types of cells. There is the endocervix, which is covered by glandular cells. This is the opening of the cervix that leads to the uterus. The exocervix is the outer part of the cervix which is covered by squamous cells. The two cell types meet at the transformation zone. This is the part of the cervix where most cervical cancers begin. Cells in the transformation zone can gradually accumulate abnormal changes over time, which lead to cancer. These pre-cancerous changes include cervical intraepithelial neoplasia, and dysplasia. Only some women with pre-cancerous changes of the cervix develop cancer. The main types of cervical cancer are:
- Squamous cell carcinomas – 90% of cervical cancers, most often begin in the transformation zone
- Adenocarcinomas – develop from glandular cells, from the endocervix
- Adenosquamous carcinomas – cervical cancers that have the features of both squamous cell carcinomas and adenocarcinomas
Pre-cancerous changes can be detected by Pap smears, so it is important to discuss with your doctor when and how often you should go for a Pap smear.
There are several different types of cells that are found in the vagina. This includes squamous cells which line the vagina (epithelium), connective tissue, muscle, lymphatic vessels and nerves, and glands that are found near the opening of the vagina. Like cervical cancer, pre-cancerous cell changes in the vagina can occur, and may develop into cancer over time. An example of a pre-cancerous change is vaginal intraepithelial neoplasia (VAIN). Vaginal cancer is quite rare, but there are many types. The more common types are:
- Squamous cell carcinoma – 90% of vaginal cancers, beginning in the epithelium of the vagina. Most commonly develop near the cervix
- Adenocarcinoma – about 10% of vaginal cancers, different types may be found in older women compared to younger women
Cancers of the vulva tend to affect the labia majora or labia minora. These are 2 sets of skin folds around the opening of the vagina. The cells of the vulva can undergo pre-cancerous cell changes as well, and this may develop into cancer over time. This is known as vulvar intraepithelial neoplasia (VIN). Most vulvar cancers tend to develop from the squamous cells, which are the main type of skin cells on the vulva. Some types of vulvar cancer are:
- Squamous cell carcinomas – there are different subtypes with different prognosis
- Adenocarcinoma – cancers of the gland cells of the Bartholin glands (found just inside the opening of the vagina)
- Melanoma – develop from the pigment-producing cells that give rise to our skin colour