How common is uterine cancer?
Uterine cancer is the fourth most common type of cancer in women in the UK, with about 9300 new cases being diagnosed in 2014 – about 3% of all cancers. Almost 6 out of 10 cases occur in women over the age of 65, with the highest rates being seen in women aged 70–74 years. Unlike some other women’s cancers, the incidence has been increasing since the early 1990s, almost doubling in the oldest age groups. Overall, it is anticipated that 1 woman in 41 will be diagnosed with uterine cancer during their lifetime.
What are the risk factors?
More than a third (37%) of all uterine cancers are linked to major lifestyle and other risk factors, of which the most important are obesity, use of hormone replacement therapy (HRT), and treatment with the breast cancer drug tamoxifen.
Being overweight or obese is the strongest risk factor for uterine cancer; it is estimated that more than a third (34%) of all uterine cancers in the UK each year are linked to overweight or obesity. The risk increases with the degree of obesity, being more than two-fold higher in women with the largest waist measurements than in those with the lowest. In addition, about 4% of cases are caused by women doing less than 150 minutes a week of physical activity.
Overall, about 1% of all uterine cancers are linked to HRT use. Compared with women who have never used HRT, the risk of uterine cancer is more than twice as high in women who have used oestrogen-only preparations at any time in their lives, although it decreases after treatment is stopped. In contrast, the risk of uterine cancer is decreased by more than a fifth (22%) in women who have used combined oestrogen-progesterone HRT, compared with those who have not.
Another factor that increases the risk of uterine cancer is treatment with tamoxifen in women with breast cancer. Among breast cancer survivors, the risk is three times higher in women aged 55–69 who have used tamoxifen for about 5 years than in those who have never used tamoxifen. However, tamoxifen does not seem to affect the risk of uterine cancer in younger women.
A number of factors have been shown to decrease the risk of uterine cancer, of which the most important is oral contraceptive use. The risk is reduced by more than a quarter (24–43%) in women who have used oral contraceptives at any time in their lives, particularly if they used them for more than 5 years, and this lower risk persists for about 20 years after stopping oral contraceptives. In the UK, it is estimated that about 17% of uterine cancers each year are prevented by oral contraceptive use.
The risk of uterine cancer is about a third lower in women who have had children than in childless women, and decreases with the number of children.
Physical activity is also associated with a lower risk of uterine cancer, possibly because physically active women tend to have a lower body weight than those who are inactive.
How is uterine cancer diagnosed?
The most common symptom of uterine cancer is abnormal bleeding from the vagina, particularly in women who have passed the menopause, although it is important to remember that this can also be a symptom of other conditions affecting the uterus, and that only a minority of women with such bleeding will actually have cancer.
The most common tests used to diagnose uterine cancer are transvaginal ultrasound and taking a sample (a biopsy) of the womb lining.
In a transvaginal ultrasound scan, a scanner is inserted into the vagina and projects sound waves which bounce off the organs in the body and are picked up by a microphone incorporated in the scanner, which converts them into an image on a screen. The procedure usually takes about 15 minutes. Ultrasound scanning is painless, although it may be slightly uncomfortable.
Biopsy samples of the womb lining (the endometrium) may be needed to determine whether cancer is present. Biopsies can be taken in a number of ways.
In an aspiration biopsy, a thin tube is inserted into the womb through the vagina and the biopsy taken by gentle suction. The procedure takes only a few minutes, and most women can go home immediately afterwards. Period-like cramping pains may occur during or after the procedure, but this can usually be treated with mild painkillers such as paracetamol.
Biopsies may also be taken by hysteroscopy, in which an instrument called a hysteroscope is inserted under local or general anaesthetic through the vagina and into the womb. Liquid is passed through the hysteroscope to inflate the womb and improve the doctor’s view, and a sample of the womb lining is taken for examination. The procedure takes about 10 minutes. As with aspiration biopsy, some cramping may occur during or after the procedure, but this can usually be controlled with mild painkillers. Vaginal bleeding may also occur, and this may last for 7–10 days.
How is uterine cancer treated?
The treatment of uterine cancer has improved dramatically in recent years, resulting in more women than ever before surviving the disease for many years. Today, more than three quarters (78%) of women with uterine cancer will survive for 10 years or more.
The treatment of uterine cancer may include surgery, chemotherapy and radiotherapy. Your doctors will discuss the different options with you, to help you make the right choice for you.
Almost all women with uterine cancer will require surgery to remove the cancer. The extent of the operation will depend on how large the cancer is, and whether it has spread to other organs outside the womb. If the cancer is still confined to the womb, the womb and ovaries will be removed in an operation called a total hysterectomy or bilateral salpingo-oophorectomy. For intermediate-risk cancers, sampling the pelvic lymph nodes is usually recommended, while for high-risk cancers more extensive sampling of the lymph nodes covering the aorta (the largest blood vessel in the body) and the omentum (a large flap of fatty tissue that hangs down from the stomach and covers some of the abdominal organs) may be recommended. In many cases, surgery for uterine cancer can be performed by keyhole surgery (also called minimal access surgery or laparoscopic surgery). In some cases of advanced womb cancer, or if the cancer has come back after previous surgery, more surgery may be needed to remove as much of the cancer as possible.
Most women who undergo surgery for uterine cancer will also be offered radiotherapy or chemotherapy to reduce the chance of the cancer coming back. Radiotherapy may be given either as a beam of radiation delivered from a machine called a linear accelerator (external radiotherapy), or as a radioactive source that is inserted into the womb via the vagina (internal radiotherapy, or brachytherapy). External radiotherapy is usually given in short daily sessions on Monday to Friday for 5 weeks, whereas internal radiotherapy is most usually given as 2–4 sessions of 10–15 minutes. As well as aiming to prevent the cancer from coming back after surgery, radiotherapy may also be used to treat cancer that has returned, or instead of surgery in women who are not fit enough for an operation.
Chemotherapy may be offered to women who are at high risk of uterine cancer returning after surgery, or to women with advanced disease. A number of drugs may be used, either individually or in combination. The most commonly used drugs are: