Leiomyosarcoma (LMS) is a rare form of sarcoma (cancer arising from bone, connective tissue and/or soft tissue) that develops in smooth muscle cells. It is most commonly found in the abdomen or uterus; however it can also be found in the skin, blood vessels, or bones.
There are two kinds of muscle cells: smooth muscle cells and skeletal muscle cells. Smooth muscle cells are responsible for involuntary movement, and are found within organs, glands, and blood vessels. They aid in food digestion, pumping blood throughout the body, urine flow and pregnancy contractions. Cancer that originates from smooth muscles is called leiomyosarcoma (LMS). In contrast, skeletal muscle cells are responsible for voluntary movement, and are attached to the bones in the body. They enable movement by contracting and relaxing in response to voluntary messages sent by the brain. Cancer that originates in skeletal muscle cells is called rhabdomyosarcoma (RMS).
LMS is more common in women, and tends to be diagnosed over the age of 50. However, anyone can develop this disease.
Types of Leiomyosarcoma
There are several different types of LMS, which are classified by the location they develop in.
Leiomyosarcoma of Soft Tissue
LMS of soft tissue is the most common type of LMS. It is most commonly found in the retroperitoneum (a space located behind the abdomen that contains many important bodily structures, such as the kidneys) and the uterus, however it can also occur in the abdominal organs or in the extremities. This type of LMS is often aggressive, and may not have as good of a prognosis as other LMS subtypes.
For more information on Leiomyosarcoma of the uterus, please refer to the Rare Cancers Australia Uterine Sarcoma page.
Leiomyosarcoma of Cutaneous Origin
LMS of cutaneous origin, also known as LMS of the skin, is a less common type of LMS that tends to develop in the middle layer of the skin (dermis). These tumours are thought to arise from pilar arrector muscles, which are tiny muscles attached to hair follicles in the skin that contract when we are cold in order to generate heat. Unlike other types of LMS, this subtype is slightly more common in men. While cutaneous LMS can be aggressive and metastasise, this type of tumour can have a good prognosis.
Leiomyosarcoma of Vascular Origin
LMS of vascular origin, also known as LMS of the blood vessels, is a very rare type of LMS. It is most likely to develop in larger veins, such as the inferior vena cava (carries deoxygenated blood from the lower parts of the body to the heart to become oxygenated) and pulmonary arteries (carry deoxygenated blood from the heart to the lungs to become oxygenated). In rare cases, it may also develop in the peripheral arteries (supply oxygenated blood from the heart to the rest of the body). Vascular LMS can be aggressive, and may not have as good of a prognosis as other types of LMS.
Leiomyosarcoma of the Bone
LMS of the bone is a very rare type of LMS that usually develops in the long bones of the body, such as the femur (thigh bone), humerus (upper arm bone), radius and ulna (forearm bones), and fibula and tibia (lower leg bones). Unlike most types of LMS, this type is more common in males. LMS of bone is often aggressive, and may not have as good of a prognosis as other types of LMS.
Treatment
If LMS is detected, it will be staged and graded based on size, metastasis (whether the cancer has spread to other parts of the body) and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you.
TNM Staging System
Cancers can be staged using the TNM staging system:
- T (tumour) indicates the size and depth of the tumour.
- N (nodes) indicates whether the cancer has spread to nearby lymph nodes.
- M (metastasis) indicates whether the cancer has spread to other parts of the body.
This system can also be used in combination with a numerical value, from stage 0-IV:
- Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissue.
- Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and had not spread to lymph nodes. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localised cancer.
- Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also known as localised cancer.
- Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advanced or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Grade I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
FIGO Staging System
Gynaecological cancers, such as uterine LMS, can be staged using the Federation of Gynaecology and Obstetrics (FIGO) system from stage I to IV:
- Stage I: cancer cells are confined to the uterus only. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby organs in the pelvis, such as the ovaries, fallopian tubes, bladder and/or bowel. This is also known as localised cancer.
- Stage III: the cancer has become larger and has spread beyond the pelvis into the lining of the abdomen (peritoneum). Lymph nodes are also often affected. This is also known as advanced or metastatic cancer.
- Stage IV: the cancer has spread to more distant organs, such as the lungs or the liver. This is also known as advanced or metastatic cancer.
Treatment Options
Once your tumour has been staged and graded, your doctor may recommend genetic testing, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Treatment is dependent on several factors, including fertility (if tumour is in the uterus), type, stage of disease and overall health.
Treatment options for LMS may include:
- Surgery to remove as much of the tumour as possible (varies based on location).
- Radiation therapy.
- Chemotherapy.
- Targeted therapy.
- Clinical trials.
- Palliative care.
For more information on the treatment options, please refer to the Rare Cancers Australia Treatment Options page.
Treatment for Uterine LMS and Fertility
Treatment for uterine LMS may make it difficult to become pregnant. If fertility is important to you, discuss your options with your doctor and a fertility specialist prior to the commencement of treatment.
Risk factors
While the cause of LMS remains unknown, the following factors may increase the likelihood of developing the disease:
Not everyone with these risk factors will develop the disease, and some people who have the disease may have none of these risk factors. See your general practitioner (GP) if you are concerned.
Early symptoms
Symptoms of LMS often vary based on location.
General Symptoms of Leiomyosarcoma
General symptoms of LMS may include:
- Pain in affected area.
- Swelling.
- Mass in affected area.
- Fatigue.
- Fever.
- Unexplained weight loss and/or loss of appetite.
- Malaise (general feeling of unwell).
- Nausea and/or vomiting.
Symptoms of Gastrointestinal Leiomyosarcoma
In addition to the general symptoms listed above, patients with LMS in the gastrointestinal tract may experience:
- Changes in bowel habits, such as black and foul-smelling stools.
- Vomiting of blood.
- Abdominal discomfort.
Symptoms of Uterine Leiomyosarcoma
In addition to the general symptoms listed above, patients with LMS in the uterus may experience:
- Abnormal vaginal bleeding (not associated with menstruation).
- Abnormal vaginal discharge.
- Changes in bladder and/or bowel habits.
- Abdominal or pelvic pressure and/or pain.
Symptoms of Cutaneous Leiomyosarcoma
In addition to the general symptoms listed above, patients with LMS in the skin may experience:
- Pink, purple, brown, or red skin discolouration.
- Painful lesions on the skin.
- Crusting and/or ulceration of affected area.
- Itching.
- Burning.
- Bleeding.
Symptoms of Vascular Leiomyosarcoma
In addition to the general symptoms listed above, patients with LMS in blood vessels may experience:
- Hepatomegaly (enlargement of the liver).
- Jaundice (yellowing of the skin and/or the whites of the eyes).
- Ascites (fluid build-up in the abdomen).
- Lower extremity oedema (swelling of the ankles, feet, and legs).
- Abdominal pain.
- Dyspnea (shortness of breath).
- Chest discomfort.
Symptoms of Leiomyosarcoma in the Bone
In addition to the general symptoms listed above, patients with LMS in bones may experience:
- Inconsistent pain in affected bone.
- Pain in affected bone that becomes worse at night.
- Easily broken bones.
- Numbness in affected area.
Not everyone with the symptoms above will have cancer, but see your general practitioner (GP) if you are concerned.
Diagnosis/diagnosing
If your doctor suspects you have a LMS, they may order the following tests to confirm the diagnosis and refer you to a specialist for treatment.
Physical examination
Your doctor will collect your overall medical history, as well as your current symptoms. Following this, they may examine your body to check for any abnormalities.
Imaging & blood tests
The doctor will take images of your body using magnetic resonance imaging (MRI), a computed tomography scan (CT scan), and/or positron emission tomography (PET scan), depending on where it is suspected the cancer is. The doctor may also look at other parts of the body and looks for signs of metastasis. Additionally, a blood test may be taken to assess your overall health and help guide treatment decisions.
Biopsy
Once the location(s) of the cancer has been identified, the doctor will perform a biopsy to remove a section of tissue using a needle. The tissue sample will then be analysed for cancer cells. This can be done by a fine needle aspiration (FNA) or a core needle biopsy (CNB).
Prognosis (Certain factors affect the prognosis and treatment options)
While it is not possible to predict the exact course of the disease, your doctor may be able to give you a general idea based on the rate and depth of tumour growth, susceptibility to treatment, age, overall fitness, and medical history. Generally, early-stage LMS have a better prognosis and survival rates. However, if the cancer is advanced and has spread, the prognosis may not be as good and there may be a higher risk of cancer recurrence. It is very important to discuss your individual circumstances with your doctor to better understand your prognosis.
References
Some references are to overseas websites. There may be references to drugs and clinical trials that are not available here in Australia.