Uterine sarcoma is a – rare, aggressive, malignant and recurrent type of uterine cancer. In most cases, it is seen in elder women with an average age of 50-70 years. The diagnosis is difficult, symptoms vague and prognosis poorer than other types of gynaecological cancers.
Though it’s lethal, it is very rare. Uterine sarcoma represents only 1% of all gynaecological cancers and about 3–7% of all uterine malignancies. It is usually detected in postmenopausal women and the diagnosis is often accidental.
Explore more about uterine sarcoma symptoms, causes, prevention, screening, staging, treatment, statistics, survival rates and researches.
What is uterine sarcoma?
Most cancer of the uterus about 95 percent occurs in the endometrium and are termed as endometrial cancer. But in some rare instances, the cancer cells may develop in the smooth muscles or connective tissues underneath that lining. This is called uterine sarcoma.
The uterine sarcomas are aggressive with high rates of local recurrence, distant metastasis and poor prognosis with overall two-year survival less than 50%. The high recurrence and silent aggressive growth make it difficult to cure.
Although infrequent, uterine sarcomas are the most lethal type of gynaecological cancers. The aetiology of uterine sarcomas is still unclear. There are no reliable methods to diagnose uterine sarcoma before surgery. Also, the symptoms of uterine sarcoma are often vague and non-specific.
Types of uterine sarcoma
There are three main types of uterine sarcoma categorized on the basis of their origin and severity – Uterine leiomyosarcoma, Endometrial stromal sarcoma, Undifferentiated sarcoma.
Most studies of uterine sarcomas report leiomyosarcoma as the commonest with an incidence of 55 %. This is followed by carcinosarcomas with 30 % incidence rate. And the rarest is endometrial stromal sarcoma with 15 % of reported cases.
Uterine leiomyosarcoma – This is the most commonly occurring type of uterine cancer. It starts in the muscular wall of the uterus also known as myometrium.
Endometrial stromal sarcoma – This is the rarest type. It starts in the connective tissue supporting the endometrium. This is further sub categorized into two types –
- Low Grade ESS – The cancer cells look much like normal cells. The cells tend to grow slowly and they have a better prognosis.
- High Grade ESS – The cancer cells look very different from normal cells. They grow quickly and are often found at a later stage when the tumor is large and hard to treat.
Undifferentiated sarcoma – This is also a rare type of uterine sarcoma. It is similar to endometrial stromal sarcoma but is much more aggressive. It grows and spreads more quickly.
The uterus is the hollow pear-shaped womb located between the bladder and rectum. The uterus is an expandable organ where the entire fetus development occurs, from embryo plantation to complete growth.
The uterus has two layers –
- the myometrium or the outer muscular layer,
- the endometrium, the inner lining.
Functions of the uterus
- Receiving the embryo.
- Sheltering the foetus during pregnancy.
- Delivering the new born at term.
- Development of the embryo and foetus during pregnancy.
- Uterus also plays a vital role in continuity of life.
Occurrence rate of uterine sarcoma
Uterine sarcoma is very rare. It represents only 1% of all gynaecological cancers, about 3–7% of all uterine malignancies and 4% of uterine cancers. The annual worldwide incidence of uterine sarcoma is 0.5 to 3.3 cases per 100,000 women.
Most cases are reported in postmenopausal women in the age range of 50-70. In the U.S, about 1200 women are diagnosed with uterine sarcoma each year. The estimated number of cases of uterine sarcoma in other countries are not available.
The presenting symptoms of uterine cancer are in most cases are vague and nonspecific. Usually, it causes abnormal vaginal bleeding, abdominal or pelvic pain, or a rapidly growing tumour. Uterine sarcoma is often challenging to detect as most of the symptoms for uterine sarcoma are same as other uterine malignancies.
Here are the common symptoms of uterine sarcoma –
- Abnormal bleeding between menstrual periods or after menopause
- Lump or growth in the vagina
- Pain in the abdomen
- Frequent urination
The signs and symptoms might differ for each patient. But if the patient shows any of these symptoms or has a reason for suspicion then a visit to the gynaecologist is highly advised.
Uterine sarcoma is an aggressive kind of cancer. That means it grows rapidly and gets harder to treat with each passing day. So, in case of any suspicion early intervention is a must.
The aetiology of uterine sarcomas is still unclear. Researchers say that chromosomal translocations have an influence on a wide histological variety of sarcomas. But because of the rarity of this cancer type, the research and study on this particular type is scarce.
So far the known risk factors for uterine sarcoma are –
- Radiation therapy – Radiation therapy in the pelvis area is a known risk factor for uterine sarcoma. Women may develop uterine sarcoma 5 to 25 years after radiation therapy.
- Using Tamoxifen – Tamoxifen is a drug used in the treatment or prevention of breast cancer. It is targeted to reduce the effect of estrogen in breast tissues but amplify the estrogen impact in the uterus. Thus, increasing the risk of uterine cancer of all types. However, the benefits of this drug outweigh the risks.
- Genetics – About 5 per cent of all uterine cancer cases are linked to hereditary factors. The abnormal gene responsible for retinoblastoma increases the risk for uterine sarcoma. So, someone who had survived retinoblastoma should be more cautious.
- Pregnancy – The risk of uterine sarcoma is higher in women who had never been pregnant throughout their life. This is because during pregnancy, the production of progesterone is more and estrogen less.
Other risk factors like obesity, existing history of cancer, and familial history of cancer may also increase the risk of uterine sarcoma. However, these factors are no ultimatum for the occurrence of uterine cancer. There are a lot of other factors like the person’s general health and lifestyle choice that plays a role in most cases.
Because of the rarity of this cancer type, no large-scale studies or researches could be conducted. Hence, the aetiology and prevention of uterine cancer are not clear yet. However, knowing the risk factors and taking proper precautions can be helpful.
People who undergo radiation therapy or take tamoxifen for breast cancer treatment, should consult their healthcare provider to access the risk. In most cases, the benefits of these treatment methods outweigh the risks of developing a rare cancer like uterine sarcoma.
Other preventive approaches include –
- Losing weight
- Managing diabetes
- Taking birth control
- Eating healthy
- Regular health check-up.
Uterine Sarcoma is staged according to the spread and severity of the cancer cells. Staging is very important for proper diagnosis, treatment and prognosis. Traditionally, uterine sarcoma is staged in the same way as endometrial carcinoma because of the rarity of its occurrence, improved understanding is difficult.
Here is the current staging of uterine sarcoma –
- Stage I: In this stage, cancer is limited in the uterus only. It is further sub-divided into two stages –
- Stage IA – In thisstage, cancer cells are in the endometrium or halfway through the myometrium.
- Stage IB – Cancer cells have spread halfway or more into the myometrium.
- Stage II: Cancer cells have spread into connective tissue of the cervix, but has not spread outside the uterus.
- Stage III: In this stage, cancer cells have spread beyond the uterus and the cervix but not beyond the pelvis. This stage is divided into –
- Stage IIIA – Cancer has spread to the outer layer of the uterus, fallopian tubes, ovaries, or ligaments of the uterus.
- Stage IIIB – Cancer has spread to the vagina or the connective tissue and fat around the uterus.
- Stage IIIC – Cancer has spread to lymph nodes in the pelvis.
- Stage IV: In this stage, cancer has spread beyond the pelvis. It is further divided into –
- Stage IVA: Cancer has spread to the bladder or bowel wall.
- Stage IVB: Cancer has spread to other parts of the body beyond the pelvis.
- Recurrent Uterine Sarcoma
Uterine sarcoma is highly recurrent, that means it can come back even after its completely treated once. About 70% of women with stage I and II uterine sarcoma reports of recurrence within an average period of 8 to 16 months of initial diagnosis. The cancer may come back in the uterus, pelvis or in any other part of the body.
The survival rate is an analysis of the successful treatment of uterine cancer over a particular period of time. The survival rates mostly depend on the stage of the cancer and the spread of the cancer. Since, uterine sarcoma is sub-divided into three types depending on the spread, the survival rate also differs for each.
Endometrial Stromal Sarcoma
The survival rates largely vary depending on the age, general health, race, and a lot of other factors of a particular patient. Hence, these numbers do not guarantee the safety or danger of a particular stage. The numbers just define a probability calculated by considering the past record of patients with the same disease.
The rapid growth of uterine sarcoma results in early metastases and that’s why early diagnosis of the disease is crucial. However, currently, there is no particular screening tests that can identify uterine sarcoma in asymptomatic women. That’s why postmenopausal women with known risk factors are recommended to go yearly check-ups.
The diagnosis of uterine sarcoma in most cases is made retrospectively after surgical removal of a presumed benign uterine neoplasm. This is because imaging diagnostic tests like ultrasound, CT scan, or MRI cannot accurately distinguish between benign leiomyoma and malignant sarcoma.
The information obtained from imagine modalities is not adequate. A special MRI exam in combination with a blood test for serum lactic dehydrogenase (LDH) helps in accurate diagnoses. Also, MRI-guided biopsy may be helpful in early detection.
Novel techniques that use diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) helps in classifying patients into two groups: patients with low-risk disease that is likely benign, and those with high-risk. These are promising techniques that need further evaluations.
Here is a look at the standard procedure followed for the diagnosis of uterine sarcoma –
- Physical Examination – If the doctor suspects uterine cancer, he or she will first perform a physical examination. In this, the doctor would check the vagina, cervix, uterus and fallopian tubes for any malignant growths. The doctor inserts hand into the vagina and rectum to feel for unusual changes.
- Medical History – The doctor would take into account the past medical records of the patient as well as that of the close family members. This is important to analyse the risk factors, determine the treatment procedure and gauge the prognosis.
- Pap test – The doctor might perform a Pap test in which a sample of cells from the cervix and uterus is extracted using a speculum (an instrument used to widen the vagina). The cells are then examined under a microscope for cancerous growths.
- Transvaginal ultrasound – For suspicion of uterine cancer, the doctor might get a transvaginal ultrasound. In this process, the doctor uses a specialized transducer which is inserted in the vaginal canal for about 2 to 3 inches. It creates images of soft tissue structures by sending sound waves.
- Endometerial biopsy – Biopsy is often the most accurate diagnostic test. In case of uterine cancer too, the doctor might recommend an endometrial biopsy. A tissue sample is taken from the endometrium (the lining of the uterus) for examination. However, simple biopsy does not provide adequate information to identify if the cancer is uterine sarcoma or something else.
- Dilation and curettage (D&C): In this process, a minor surgery is done to remove tissues from the uterus. For this the cervix is dilated (widened) and a thin instrument called a curette is inserted. The doctor then uses a suction device or a scraping instrument, called a curette, to clean out tissue from the uterus.
The most preferred choice of treatment for uterine sarcoma is surgery. In most cases, surgery is done to remove the uterus, sometimes along with the fallopian tubes and ovaries. This is often followed by radiation, chemotherapy, hormone therapy or targeted therapy. Targeted therapy is opted for advancer cancers.
The doctor may choose one or more of the therapies for treating uterine sarcoma. For patients with critical health condition, where surgery is not a viable option, doctors opt for a combination of chemotherapy or hormone therapy.
After the cancer has been completely removed with surgery, the doctor may recommend adjuvant treatment. It is to help keep the cancer from coming back. Since, uterine sarcoma has a high recurrent rate with over 70% of patients reporting of cancer recurrence within one year, hence, adjuvant treatment is imperative.
Here is a detailed outline of the treatment procedures.
Surgery is the most preferred treatment option for uterine sarcoma. This procedure removes the cancerous mass sometimes along with some surrounding tissues. The complexity of surgery increases with the spread and severity.
Surgery for uterine sarcoma is classified as –
- Hysterectomy — It means surgical removal of the uterus. Hysterectomy is further classified as:
- Abdominal hysterectomy – An incision from about pubic bone to belly button is made to take out the uterus and cervix through this opening.
- Vaginal hysterectomy – A small cut is made at the top of vagina to remove the uterus and cervix through the vagina.
- Laparoscopic-assisted vaginal hysterectomy – Small cuts are made in the belly and through one cut a long, thin tool called a laparoscope is inserted. The laparoscope lets the surgeon see the uterus, fallopian tubes, and ovaries. The surgeon places other tools through other cuts to detach the uterus which is then removed through a small cut at the top of your vagina.
- Radical hysterectomy – Radical hysterectomy is done when cancer has spread to the cervix or around the uterus. At this phase, the surgery is done to remove the uterus, cervix, both ovaries, both fallopian tubes and some surrounding tissue.
Radical hysterectomy can be done through abdominal incision or through laparoscopic vaginal incision.
- Salpingo-oophorectomy —This surgery may be done along with hysterectomy. In this procedure, the surgeon takes out the uterus, cervix, both the fallopian tubes and both ovaries. Taking out the ovaries removes the main source of hormones that can make certain kinds of cancer cells grow.
- Lymphadenectomy — If the cancer has spread then the surgeon will take out lymph nodes from the pelvis to check for cancer cells. If cancer cells are found in the lymph nodes that means cancer has spread outside the uterus. The doctor might need to remove the lymph nodes at the time of hysterectomy.
- Laparotomy — removal of lymph nodes using a laparoscope, which is inserted through a small incision in the abdomen.
Possible risks or side effects of surgery
Surgery is an invasive kind of treatment. And there is certain risk and side effects associated with each type of surgery. But the risks or side effects often outweighs the benefits and that’s why it’s the most preferred option for treating uterine sarcoma.
- Excess bleeding
- Damage to internal organs
- Swelling in the legs
- Pain where the incisions were made
- Vaginal discharge or bleeding
- Trouble urinating or having bowel movements
Radiation therapy is a treatment for cancer which uses high energy X-rays to kill or shrink cancer cells while minimizing the damage to healthy cells. Radiation therapy can either be internal or external.
- External radiation – The radiation machine is pointed at the skin over the tumor. The machine doesn’t touch the patient or hurt them. This process is quick.
- Internal radiation – Radioactive material is inserted into the body near the area of cancer cells through flexible tubes called catheters or metal rods. The radiation material travels a very short distance to kill nearby cancer cells.
Side effects of radiation therapy
- Nausea and vomiting
- Changes to the skin
- Irritations in the bladder
- Swelling in the legs
Chemotherapy is a popular cancer treatment that uses medications to kill or to slow the growth of cancer cells. These medications are often given intravenously but sometimes it can be administered orally too. In some cases of uterine sarcoma, radiation therapy and chemotherapy are given together.
Side effects of chemotherapy
Chemotherapy drugs can have major side effects. But these side-effects are mostly temporary and can be managed to a great extent with proper care.
The most common side effects of chemotherapy are:
- Nausea and vomiting
- Hair loss
- Loss of appetite
- Low blood count
Hormones, specially estrogen production has a major role in causing uterine cancer. Hence, using hormone therapy can help to stop the growth of cancer cells by blocking the action of hormones. Most hormone therapy medicines are pills that can be simply taken at home and few are injections.
Hormone therapy can be used after surgery to lower the rate of recurrence. It can also be used if the cancer has spread widely and surgery is not an option, hormone therapy can help shrink the size of cancer. Hormone therapy is also used when radiation and chemotherapy are not good options. It is also used in patients with early‐staged disease who desire to preserve fertility.
The high rate of recurrence and metastasis and limited clinical benefits of surgery and chemoradiotherapy, makes hormonal therapy a good option. Hormones used in treating uterine sarcoma include progestins, gonadotropin-releasing hormone agonists, and aromatase inhibitors.
Side effects of hormone therapy
The common side effects of hormone therapy is much like that of menopause. These includes –
- Hot flashes
- Vaginal dryness
- Night sweats
- Weight gain
- Joint or muscle pain
- Menstrual blood clots
- Weakened bones.
Uterine sarcoma is a rare-tumour with high malignant potential and poor prognosis. Because of its high recurrent nature, there is no curative treatment as of now. Also, the rarity of this disease adds to the difficulty of research and studies.
In case of uterine sarcoma, the only prognostic factor related to survival is the stage of the disease at diagnosis. Adjuvant therapies also do not offer much benefit in uterine sarcomas, it also does not alter the survival rates.
However, like any other cancer, for uterine sarcoma too open conversations about the symptoms, side-effects, mental health, emotional conditions, coping and recovering helps in better prognosis.
Uterine sarcoma has very high recurrence probability. Women who have been successfully treated for uterine sarcoma have a greater risk for certain other types of cancer, including breast cancer, colon cancer, bladder cancer, vaginal cancer, and rectal cancer.
Hence, women who have undergone treatment for uterine sarcoma should continue to follow-up for regular check-up. Also, postmenopausal women should visit a gynaecologist for an annual check-up. Young women who have familial history of cancer should also be more vigilant about abnormal bleeding, discharge or other changes in the body. Uterine sarcoma is very rare but lethal. Hence, being aware and alert about this cancer is very important for women of all ages.
Uterine Sarcoma is very aggressive in nature, that means it progresses at a rapid pace. So, if you spot any abnormal bleeding, discharge, pain or mass in the abdomen, act fast. Visit a gynaecologist, discuss your symptoms and ask the right questions.
To Know More: Endometrial Cancer