Uterine leiomyosarcoma is a rare malignant (cancerous) tumour that grows in the smooth muscle lining the walls of the uterus (myometrium). It is estimated to occur in 6 out of every 1,000,000 women in the United States annually.
A short lesson…
There are essentially two types of muscles in the body: voluntary and involuntary. Smooth muscles are involuntary muscles; the brain has no conscious control over them. Smooth muscles react involuntarily in response to various stimuli.
Leiomyosarcoma is a form of cancer. The term “cancer” refers to a group of diseases characterised by abnormal, uncontrolled cellular growth that invades surrounding tissues and may spread (metastasize) to distant bodily tissues or organs via the bloodstream, the lymphatic system, or other means.
Leiomyosarcoma, in general, is classified as a soft tissue sarcoma, whilst sarcomas are malignant tumours arising from the connective tissues – which connect, support, and surround the structures and organs in the body. Soft tissue includes fat, muscle, never, tissue surrounding the joints and blood and lymph vessels.
The exact cause of leiomyosarcoma, including uterine leiomyosarcoma, is unknown.
Possible Causes? Fertile ground for debate
The exact cause of uterine leiomyosarcoma is unknown. They often occur spontaneously, for no apparent reason. In extremely rare cases, some researchers believe they may signify a malignant change (transformation) of a benign (noncancerous) fibroid. However, other researchers argue that the malignant transformation of fibroids is unproven. Fibroids are the most common tumours affecting women and often appear during childbearing years. Fibroids may also be known as leiomyomas or myomas. Most fibroids do not cause any symptoms or complications.
Researchers speculate that genetic and immunologic abnormalities, environmental factors (e.g., exposure to ultraviolet rays, certain chemicals, ionizing radiation), diet, stress, and/or other factors may play contributing roles in causing specific types of cancer. Investigators are conducting ongoing basic research to learn more about the many factors that may result in cancer.
Leiomyosarcomas are associated with specific genetic and environmental risk factors. Certain inherited conditions in families may increase the risk of developing leiomyosarcoma. These disorders include Gardner syndrome, Li-Fraumeni syndrome, Werner syndrome, neurofibromatosis and several immune deficiency syndromes. The exact association between leiomyosarcoma and these disorders is not understood. (For more information on these disorders, choose the specific disorder name as your search term in the Rare Disease Database.)
Researchers have speculated that exposure to high-dose radiation and certain chemicals (e.herbicides) may be linked to an increased risk of developing leiomyosarcoma, but no definitive link has been established.
Differential diagnosis!
There are a couple of disorders which have similar symptoms and hence it may be difficult to differentiate. These include:
Endometrial carcinoma refers to cancer of the inner membrane lining the uterus (endometrium).
Uterine fibroids, also known as leiomyomas, are benign smooth muscle tumours of the uterus.
Interestingly, the cause for both are unknown.
Diagnosis
So how do we diagnose this condition?
Pathologic review is a key diagnostic aspect distinguishing malignant leiomyosarcoma from its benign counterpart, the leiomyoma.
Specialised imaging techniques may be used to help evaluate the size, placement, and extension of the tumour and to serve as an aid for future surgical procedures among individuals with uterine leiomyosarcomas. Such imaging techniques may include computerised tomography (CT) scanning, magnetic resonance imaging (MRI) and ultrasound. During CT scanning, a computer and x-rays are used to create a film showing cross-sectional images of certain tissue structures. An MRI uses a magnetic field and radio waves to produce cross-sectional images of particular organs and bodily tissues. During an ultrasound, reflected sound waves create an image of the uterus. Laboratory and specialised imaging tests may also be conducted to determine possible infiltration of regional lymph nodes and the presence of distant metastases.
Treatment
Specific therapeutic procedures and interventions may vary, depending upon numerous factors, such as primary tumour location, the extent of the primary tumour (stage), degree of malignancy (grade); whether the tumour has spread to lymph nodes or distant sites; an individual’s age and general health; and/or other elements.
The primary treatment for uterine leiomyosarcoma is the surgical removal of the entire tumour and any affected tissue. Total surgical removal of the uterus (hysterectomy) is usually performed. Usually, surgical removal of the fallopian tubes and ovaries (bilateral salpingo-oophorectomy) may also be recommended, especially for women who are menopausal or have metastases.
Anti-cancer drugs used alone or in combination (chemotherapy) and radiation therapy have been used to treat individuals with leiomyosarcoma following surgery (adjuvant therapy) with limited benefit. Investigational therapies are underway to develop new chemotherapeutic combinations that may prove beneficial in treating leiomyosarcomas. In some cases, radiation therapy may be used before surgery to reduce the size of a tumour.
Each patient who walks in with this condition has a different set of symptoms and body anatomy. They require specialised treatment and therapies to treat their specific symptoms. We must make way for more targeted therapies to treat and possibly cure this disease.
Written by: Svasti Tewari
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