Leiomyosarcoma – from the National Cancer Institute (NCI):

What is leiomyosarcoma?

Leiomyosarcoma, abbreviated as LMS, is an uncommon cancer that develops in the smooth muscles. These muscles are present in the hollow organs of the body, such as the intestines, stomach, bladder, and blood vessels. Additionally, females have smooth muscle in the uterus. These smooth muscle tissues play a vital role in facilitating the movement of blood, food, and other substances throughout the body, operating seamlessly without conscious awareness.

Leiomyosarcoma is characterized as an aggressive cancer, demonstrating rapid growth. This malignancy predominantly manifests in the abdomen or the uterus.

How common is LMS?

Leiomyosarcoma, constituting 10% to 20% of soft tissue sarcoma cases, is a distinctive type within this category. Predominantly affecting adults rather than children, an estimated 20 to 30 children are diagnosed with LMS in the United States annually. Specifically, LMS of the uterus is reported to impact approximately 6 per 1 million people each year in the United States.

How is LMS diagnosed?

Symptoms vary based on the tumor’s location and size. In some cases, individuals with LMS may not initially experience symptoms. However, as the tumor grows larger, potential symptoms may include:

  • Pain
  • Unintentional weight loss
  • Nausea and vomiting
  • Lump under the skin


If you’re experiencing symptoms of LMS, your doctor will employ advanced imaging scans such as MRI, CT, angiography, and PET to meticulously assess the location and size of the tumor. Additionally, they will conduct thorough examinations to detect any indications of the tumor spreading to other areas of the body.


To check if the tumor is LMS, your doctor will do a biopsy, taking a small sample from the tumor with a needle. An expert, called a pathologist, will study cells from the sample under the microscope to see what kind of tumor it is.

Sometimes, LMS may be mistaken for a different type of tumor or condition using imaging scans. A biopsy will confirm the tumor is LMS. Getting the correct diagnosis is very important in order to get the right treatment.

How is LMS treated?

Individualized treatment plans are crafted based on the size and location of the tumor for each patient. Seeking guidance from an expert in LMS treatment is crucial to determining the most effective approach for addressing your specific tumor. For assistance in finding experts near you, reaching out to the National Leiomyosarcoma Foundation and the NCI MyPART is recommended.


Surgery stands out as the optimal choice for treating LMS. Complete removal of the tumor offers a high likelihood of curing LMS. Conversely, if residual cancer cells persist, there is an increased risk of the cancer recurring in the original location or potentially spreading to different parts of the body.


Radiation therapy:

Radiation therapy, often administered concurrently with surgery, involves precisely targeting the tumor area to impede its regrowth following removal.


In instances where LMS tumors are substantial or cancer cells have metastasized, chemotherapy is integrated with surgical interventions.




Is there a hereditary predisposition for Leiomyosarcoma?

No. LMS without an underlying genetic condition is not known to run in families.

How does LMS form?

The exact factors triggering the formation of LMS remain unknown. Ongoing scientific research strives to unravel the intricate mechanisms of cancer development, although definitive proof can be challenging to establish. Nevertheless, certain genetic conditions are linked to LMS, including hereditary retinoblastoma, Li-Fraumeni syndrome, neurofibromatosis type 1, tuberous sclerosis, nevoid basal cell carcinoma syndrome, Gardner syndrome, and Werner syndrome.

What is the prognosis for someone with LMS?

Prognosis, which reflects the expected impact of a disease over the long term, varies for each individual. Numerous factors, including:

  • Where the tumor is in your body
  • If the cancer has spread to other parts of your body
  • How much of the tumor was taken out during surgery

For personalized information on your prognosis, it is crucial to have a conversation with your doctor. Additionally, the NCI provides resources to assist in comprehending cancer prognosis.

Physicians gauge the survival rates of LMS by analyzing the historical outcomes of groups with this condition. However, due to the limited number of pediatric LMS patients, these rates may lack precision.

In cases where LMS is detected early and surgically removed, the prognosis is favorable, often leading to a complete recovery. However, when LMS is sizable or has metastasized to other areas of the body, the treatment becomes more challenging, and the prognosis tends to be less optimistic.



Facing Treatment for Leiomyosarcoma:

Table of Contents:

  • How It Forms
  • Symptoms and Diagnosis
  • Stages
  • Treatment
  • Survival
  • Support

Authored by Jennifer Welsh and published on June 16, 2023. Medically reviewed by Doru Paul, MD. Print.

Leiomyosarcoma (LMS) is a very rare, abnormal growth in the smooth muscles of many organs—most often the stomach, intestines, and uterus. Leiomyosarcoma tumors usually spread to other tissues and distant organs. They can be unpredictable—growing and spreading very quickly, making them deadly. 

Frequently, traditional cancer treatments such as radiation and chemotherapy exhibit limited efficacy against leiomyosarcoma. Despite its potentially life-threatening nature, various factors play a significant role in determining an individual’s prognosis. Notably, in its early stages, leiomyosarcoma can be effectively cured.

This article will delve into the prognosis of leiomyosarcoma, explore the life-threatening aspects of this condition, and outline key symptoms to be vigilant about. Additionally, it will provide insights into various treatment options and discuss the different stages of leiomyosarcoma.

Leiomyosarcoma Formation: Cancer in Smooth Muscles:

Leiomyosarcoma, a form of cancer originating in the smooth muscles, typically occurs in the hollow organs of the body, such as the intestines, stomach, bladder, and blood vessels. These smooth muscles function autonomously, devoid of conscious control from the brain. Their vital roles encompass facilitating blood circulation, aiding the movement of food through the digestive system, and contributing to the process of childbirth.

Leiomyosarcoma most frequently originates in two primary locations: the gastrointestinal (GI) tract, encompassing the stomach and intestines, and the uterus. Less commonly, leiomyosarcomas may manifest in various areas, including blood vessels, heart, liver, pancreas, regions of the abdominal cavity, skin, bladder, and urinary tract.

What Is a Sarcoma?

Leiomyosarcoma, categorized as a type of soft tissue sarcoma, originates in the body’s smooth and skeletal muscles, tendons, fat, lymph and blood vessels, as well as nerves—comprising the soft tissues and connective tissues of the body.

Each year, the United States witnesses the diagnosis of over 15,000 new cases of soft tissue sarcoma, constituting approximately 1% of all adult cancers. Notably, leiomyosarcoma represents about 10% of these cases.

Leiomyosarcoma is considered rare, impacting individuals of all genders, with a slight predilection for those assigned female at birth. Moreover, this condition is more prevalent among middle-aged and older adults compared to children.

Research indicates that in Western countries, approximately 3 out of every 200,000 individuals are projected to develop these tumors annually. Specifically, about 6 out of every 1 million people in the United States are diagnosed with a leiomyosarcoma tumor in the uterus each year.


Leiomyosarcomas originating in the stomach and intestines are frequently categorized as gastrointestinal stromal tumors (GIST) due to their distinctive features. Notably, they tend to exhibit a slower growth rate compared to other forms of leiomyosarcomas. Approximately 5,000 to 6,000 cases of these tumors are diagnosed annually in the United States.

Navigating a Leiomyosarcoma Diagnosis:

While smooth muscle cancers, such as leiomyosarcoma, are exceptionally rare, their aggressive and potentially fatal nature becomes more pronounced, particularly when not identified early. Detection of leiomyosarcoma, aside from utilizing imaging tests, relies on vigilant observation for signs and symptoms indicative of a tumor.


The manifestation of a tumor depends on its location, often presenting as a palpable lump beneath the skin. Additionally, there may be associated sensations of pain or swelling in the affected area.

Leiomyosarcoma symptoms vary with tumor size, location, and potential metastasis. Larger tumors may disrupt organ function, leading to specific symptoms, such as:

  • GIST leiomyosarcoma in the digestive tract can cause bleeding and other digestive issues.
  • Uterine leiomyosarcoma can cause menstrual changes, for example such as bleeding or discharge.

Benign Leiomyoma vs. Malignant Leiomyosarcoma:

When healthcare providers diagnose leiomyosarcoma, their initial step involves ruling out a benign counterpart known as leiomyoma, which is non-cancerous. Leiomyomas, commonly referred to as fibroids, particularly when occurring in the uterus, necessitate scrutiny for cancer if they exhibit growth after menopause.

As leiomyosarcoma grows in size and extends to other organs, it can manifest symptoms indicative of metastatic cancer—where the cancer has disseminated to various parts of the body. These symptoms may include:


In the process of diagnosing leiomyosarcoma, your healthcare provider will inquire about your symptoms and medical history, conducting a thorough examination of your body.

Medical professionals may prescribe imaging examinations, including Magnetic Resonance Imaging (MRI), Computed Tomography (CT), Angiography, and Positron-Emission Tomography (PET). These diagnostic tools provide a comprehensive visualization of the tumor’s location and size, aiding the care team in determining its characteristics. Additionally, these tests assist in excluding other tumor types and evaluating whether the cancer has spread to other organs.

In addition, they will conduct blood tests to identify potential cancer indicators. A biopsy, involving the extraction of a small tissue sample, will be performed to conclusively confirm the presence of leiomyosarcoma.


There is also the possibility that they may proceed to fully excise the tumor. Surgical resection stands as the most potent treatment for leiomyosarcoma. Following the removal of the tumor, the surgeon can extract samples for a thorough examination of cancer cells. This assessment provides insights into the cancer’s aggressiveness, guiding decisions on the need for additional treatment.

Stages of Leiomyosarcoma:

Staging serves as a means for healthcare providers to assess cancers across individuals, offering insights into optimal treatments and prognosis. In sarcoma staging, considerations include the tumor’s size, extent of spread, and the microscopic appearance of cancer cells.

The tumor’s grade is ascertained by examining the cells under a microscope. When a healthcare provider performs a tumor biopsy, the sample is sent to the lab for grading. Grading delineates the extent of abnormality in the cells, gauging their wild appearance and the anticipated rate of growth.

Sarcomas undergo staging from 1 to 4, reflecting their growth and spread. A higher stage corresponds to a more advanced stage of cancer.

The tumor’s grade is assigned on a scale from 1 to 3, with higher numbers indicating a more aggressive nature. A higher grade signifies that the cancer cells appear more aberrant and exhibit increased division, highlighting the tumor’s heightened aggressiveness.

The staging of soft tissue sarcoma, according to the American Joint Committee on Cancer’s Version 7 Staging System, is delineated by tumor size and grade, as detailed below:

  • Stage 1A: The tumor is smaller than 5 centimeters (cm), and its grade is 1 or ungradable.
  • Stage 1B: The tumor is bigger than 5 cm, and its grade is 1 or ungradable.
  • Stage 2A: The tumor is smaller than 5 cm, and its grade is 2 or 3.
  • Stage 2B: The tumor is bigger than 5 cm, and its grade is 2.
  • Stage 3: The tumor is bigger than 5 cm with a grade of 3, or the cancer has spread to the lymph Nodes.
  • Stage 4: Any tumor that has spread to distant organs.

FIGO has a specific staging system for uterine sarcomas, where the tumor grade’s relevance to prognosis is less established. These stages are defined as follows:

  •  Stage 1 tumors are limited to the uterus. In stage 1A, the tumor is smaller than 5 cm; in 1B, it is larger than 5 cm.
  • Stage 2 tumors extend beyond the uterus, within the pelvis. Stage 2A tumors have spread to the regions of the Ovaries and Fallopian Tubes. Stage 2B tumors have spread to other pelvic tissues.
  • Stage 3 tumors have spread to abdominal tissue. This includes stage 3A, which has spread to one other area in the abdomen; stage 3B, which has spread to more than one area; and stage 3C, which has spread to lymph nodes in the abdomen.
  • Stage 4 tumors have spread to other organs. Stage 4A tumors have spread to the bladder or rectum, while 4B tumors have spread to distant organs.

Metastatic Leiomyosarcoma:

In general, stage 4 tumors are identified as metastatic leiomyosarcomas, signifying their spread to other areas of the body. The lungs or liver are frequently targeted sites for leiomyosarcomas’ Metastasis, potentially leading to life-threatening complications from the development of new tumors in these locations.

A study of uterine leiomyosarcomas found that they spread most frequently to the:

  • Lung
  • Brain
  • Skin or other soft tissues
  • Bone
  • Other sites (thyroid, salivary gland, heart, liver, pancreas, adrenal gland, bowel, and breast)

Recurrent Leiomyosarcoma:

Due to its aggressive and rapid spread, leiomyosarcoma carries a heightened risk of recurrence following initial treatment. Even cases successfully treated can experience a resurgence, termed recurrent leiomyosarcoma, which may remain dormant for years, reappearing long after the initial treatment.

Recurrence rates for uterine leiomyosarcomas reach up to 70%, while leiomyosarcomas in other locations demonstrate a recurrence of approximately 40%.




After Diagnosis: Leiomyosarcoma Treatment Plan

Leiomyosarcoma can be curable when detected at an early stage before spreading. Surgical removal is a common approach in such cases. For cells left behind during surgery or those that have already spread to other parts of the body, additional systemic treatments may be employed, although the likelihood of achieving a cure is reduced.

Upon a leiomyosarcoma diagnosis, your healthcare provider promptly initiates treatment, typically commencing with surgical tumor removal. Subsequent interventions may involve radiation or chemotherapy.

The required treatments are tailored to your overall health, age, and specific details about your cancer, encompassing factors such as the tumor’s location, size, grade, stage, and potential spread to other body parts.


Optimal treatment for leiomyosarcoma is surgical intervention. When detected early, before spreading, and amenable to complete removal, surgery holds the potential to cure leiomyosarcoma.

The choice of surgical options for removing the leiomyosarcoma tumor hinges on its location, size, and extent of spread to other tissues and organs. However, in instances of advanced leiomyosarcoma, surgery may not be the most viable or feasible option.

Should surgery fail to completely eradicate the tumor, leaving behind residual cancer cells either at the surgical site or in other body regions, there’s a potential for cancer recurrence. In some instances, additional surgeries may be necessary for reconstructing the affected area.

Radiation Therapy:

In cases where leiomyosarcoma has extended to other tissues, lymph nodes, or organs, supplementary treatments are essential to forestall recurrence. Radiation therapy is one such intervention, commonly administered during or immediately following surgical tumor removal. Utilizing high-energy beams, radiation therapy disrupts the genetic material of cancer cells, leading to their destruction.

If surgery is not a viable option for your tumor, standalone radiation therapy may be recommended.


Chemotherapy drugs target dividing cells, with a particular focus on rapidly growing cancer cells, especially those of an aggressive nature. In leiomyosarcoma, chemotherapy is employed when the primary tumor is sizable or when the cancer has proliferated and extended to other body regions. It is often utilized in conjunction with surgical interventions.

Chemotherapy is typically recommended for cancers that have extended to nearby tissues, lymph nodes, or other organs, as well as those that have recurred following initial surgery and treatment.

Chemotherapy drugs, designed to eliminate rapidly dividing cells, may inadvertently affect some healthy cells in the body, leading to side effects like fatigue and nausea. Individuals who are elderly or have underlying health concerns may find these side effects challenging to manage.

Experimental Treatments and Clinical Trials:

In response to limited treatment alternatives, ongoing efforts involve the development and testing of new drugs for treating leiomyosarcoma. Among these are drugs designed to inhibit the formation of new blood vessels to the tumor and those that stimulate the immune system to combat cancer.

Explore further information on clinical trials for leiomyosarcoma by visiting clinicaltrials.gov.

Leiomyosarcoma Survival and Determining Factors:

Oncologists view leiomyosarcoma as an aggressive cancer due to its rapid growth and easy spread. Prognosis hinges on factors like:

  • Location of the tumor
  • Spread of the tumor
  • How surgery went

When detected early, leiomyosarcoma can enter remission, with a favorable prognosis and a high likelihood of full recovery if surgical removal completely eliminates the tumor.