Fibrosarcoma is a rare type of cancer that affects cells known as fibroblasts. Fibroblasts are responsible for creating the fibrous tissue found throughout the body. Tendons, which connect muscles to bones, are made up of fibrous tissue.
When fibrosarcoma strikes, the body’s fibroblasts lose control and multiply excessively. This either creates fibrous tissue where it is not supposed to be or in excess quantities. Like other cancers, fibrosarcoma can spread throughout the body.
Fibrosarcoma is part of a wider family of cancers known as sarcomas. Other examples include osteosarcoma, which specifically affects bone, and rhabdomyosarcoma, which specifically affects muscle.
Rarely, fibrosarcoma can occur in bone, but it usually affects the nearby fibrous tissue, not the bone itself.
In this article, we take a look at the symptoms of fibrosarcoma, how doctors may diagnose it, and what the outlook is for people with this disease.
Fibrosarcoma is a cancer that affects the fibroblast cells.
Fibrosarcoma is not easy to identify by symptoms alone, not least of all because it shares symptoms with other forms of sarcoma.
According to Macmillan Cancer Support, the symptoms of soft tissue sarcomas, such as fibrosarcoma, take a long time to appear. When they do appear, symptoms can include:
- painless or painful swelling in various parts of the body, and especially the limbs
- a cough or breathlessness
- dark stool
- vomiting blood
- irregular bleeding from the vagina
- pain in the abdomen
Fibrosarcoma affecting bones can be even trickier to identify by symptoms alone. According to Macmillan Cancer Support, symptoms of primary bone cancer include:
- persistent pain in the area of the tumor, which might feel like a sprain or “growing pains”
- swelling around the bone, which often does not show up until the tumor is quite large
- difficulty moving a joint or limb
- numbness in areas of the body, due to the tumor pressing on nerves
- fragile, easily broken bones, as the bone has been weakened by cancer
Fibrosarcoma can occur throughout the body but is more likely to appear in specific locations, such as the soft tissues, than in others.
Fibrosarcoma of the bone is rare and around 70 percent all bone fibrosarcomas develop in the long bones — such as the thighbone, shinbone, and jawbone. The thighbone is the bone that is most commonly affected by fibrosarcoma.
Causes and risk factors
The American Cancer Society list the following risk factors for developing soft tissue sarcomas that may include fibrosarcoma:
- weakened or damaged lymph system
- radiation exposure
- certain chemical exposures, possibly including vinyl chloride, arsenic, and dioxin
- some cancer syndromes caused by inherited genetic abnormalities
A PET scan may be required to diagnose fibrosarcoma.
The American Cancer Society list a variety of tests that are routinely carried out to diagnose soft tissue sarcomas and to determine which variant of cancer is at work.
These tests include:
- standard X-rays
- CT (computed tomography) scans, which produce detailed images of the body from different angles
MRI (magnetic resonance imaging) scans, which use radio waves and magnets to map the tissues of the body
ultrasound scans, which is often done before a biopsy
- PET (positron emission tomography) scans, involving the injection and tracking of radioactive sugar
- biopsies, where a tissue sample is removed for testing
With the help of these tests, doctors can identify fibrosarcoma by examining the locations in which it most commonly appears. Specific key features also signal fibrosarcoma, such as tumors that appear without calcium buildups on X-rays.
Identifying fibrosarcoma is not always a straightforward process, however. A 2014 study warns against confusing it with osteosarcoma, which has similar features.
As a result, doctors may carry out a variety of tests, including a biopsy, to ensure a correct diagnosis.
Staging and grading
Staging is a term used to describe how far cancer has spread in the body, and how much cancerous tissue is present.
One of the most common staging systems is the number system, which ranges from 1–4 with a few secondary classes.
The number stages for soft tissues sarcomas, such as fibrosarcoma are:
1A: Tumor measures 5 centimeters (cm) or less, low or unknown grade, close to surface of the body or deep, and has not spread.
1B: Tumor larger than 5 cm, low or unknown grade, close to surface or deep, and has not spread.
2A: Tumor 5 cm or less, medium or high grade, close to surface or deep, and has not spread.
2B: Tumor larger than 5 cm, moderate grade, close to surface or deep, and has not spread.
3: Tumor larger than 5 cm, high grade, close to surface or deep, and has not spread. Alternatively, the tumor is of any size, any grade, close to surface or deep, has spread to at least one lymph node but not further.
4: Tumor has spread to another part of the body, such as the lungs or other soft tissues. The tumor can be of any size, any grade, close to surface or deep, and may or may not have spread to lymph nodes. This type is also known as secondary or metastatic cancer.
The grade of tumor is how abnormal its cells and tissues appear under a microscope. The higher the grade, the more abnormal it appears and the more quickly it is likely to grow and spread.
Radiation therapy may be used to treat fibrosarcoma, usually before or after surgery to remove a tumor.
Treatment for fibrosarcoma depends on the stage of the cancer.
The American National Cancer Institute list the following possible treatments for soft tissue sarcomas such as fibrosarcoma in adults:
- surgery to remove tumor
- radiation therapy before or after surgery
- radiation or chemotherapy before and possibly after surgery if needed
- high-dose radiation therapy for tumors that cannot be surgically removed
- surgery, including removal lymph nodes and potential radiation therapy after
- a clinical trial of surgery with chemotherapy after
- a clinical trial of regional hyperthermia therapy, which increases body temperature in specific areas
- surgical removal of cancer which has spread to lungs
A prognosis is a prediction of the development of a disease, recovery, and survival rate following treatment.
With any form of cancer, the prognosis is significantly affected by the stage at which the cancer was first identified and treated.
A prognosis typically refers to 5-year survival rate. For high-grade fibrosarcomas, 5-year survival rates are around 30 percent. For low-grade fibrosarcomas, these survival rates increase to 50–80 percent.
There do not appear to be any clear steps for specifically preventing fibrosarcoma.
The best approaches to take are avoiding exposure to the relevant risk factors as much as possible, and tending to one’s overall health.