A tumor is an abnormal mass of tissue that forms when cells grow and divide more than they should or do not die on schedule. Normally, the body creates new cells to replace old ones, and damaged cells are programmed to die. When this balance is disturbed, a tumor can form. The term “tumor” can be unsettling, but it does not automatically mean the growth is cancerous.
Benign vs. Malignant Tumors
The primary distinction between tumors is whether they are benign (non-cancerous) or malignant (cancerous). Benign tumors do not invade other tissues or spread to other parts of the body. These growths grow slowly, have a regular shape, and may have a protective covering called a capsule. Common examples include lipomas, which are tumors in fatty tissue, and skin moles.
While benign tumors are not life-threatening, they can cause problems if they grow near organs, press on nerves, or restrict blood flow. For instance, a tumor in the digestive system might obstruct food, and one near the brain can cause harm due to its location. Benign tumors that are not causing issues may be monitored, but they can be removed for cosmetic reasons or to alleviate symptoms.
Malignant tumors are cancerous, with cells that grow rapidly and invade nearby tissues. They can also metastasize, meaning cancer cells break away from the original tumor. These cells travel through the bloodstream or lymphatic system to form new tumors in distant parts of the body. This ability to spread is what makes malignant tumors dangerous.
The cellular structure of malignant tumors is also different, as the cells have abnormal chromosomes and DNA. Unlike benign tumors, malignant ones are more likely to recur after removal. Treatment for a malignant tumor is significantly different and depends on where the cancer originated.
Causes and Risk Factors
Tumor formation begins with DNA changes, or mutations, that allow a cell to grow uncontrollably. These mutations can be inherited or acquired. Some people inherit gene mutations from their parents that increase their risk for certain cancers, such as the BRCA1 and BRCA2 genes linked to breast and ovarian cancers. A family history of cancer can suggest a higher genetic risk.
Environmental exposures to carcinogens (cancer-causing substances) are also a factor in tumor development. These include:
- Tobacco smoke
- Asbestos
- Air pollutants like fine particulate matter
- Radiation from sources like ultraviolet (UV) sunlight
Lifestyle choices are also linked to cancer risk. Factors include:
- A diet high in processed foods and red meats
- Excessive alcohol intake
- Low physical activity levels
- Obesity, as excess fat cells can produce hormones that promote cancer growth
In many cases, the cause of a tumor is an interaction between multiple genetic and environmental influences.
The Diagnostic Process
Diagnosis often begins after a growth is found during a physical exam or an imaging test for an unrelated issue. In other cases, symptoms caused by the tumor lead to its discovery. Once a potential tumor is identified, imaging tests are used to create pictures of the inside of the body to visualize the mass’s size, shape, and location.
Common imaging techniques are used to see the mass. These include:
- X-rays
- Computed tomography (CT) scans, which use X-rays and a computer for detailed 3-D images
- Magnetic resonance imaging (MRI), which uses a magnet and radio waves for images of soft tissues
- Ultrasound
While these tests can detect masses, they cannot differentiate between cancerous and non-cancerous cells.
The definitive method for determining if a tumor is benign or malignant is a biopsy. In this procedure, a small sample of tissue is removed from the suspicious area for examination under a microscope. Imaging technology like ultrasound or CT may be used to guide the needle. The analysis of the sample identifies the cell type and determines if they are cancerous.
General Treatment Approaches
The treatment plan depends on whether a tumor is benign or malignant, its size, location, and the patient’s health. For small benign tumors not causing symptoms, the approach may be observation, sometimes called “watchful waiting.” If a benign tumor needs to be addressed, surgery to remove the mass is a common and often sufficient treatment.
For malignant tumors, treatment is more complex and involves a combination of strategies. Surgery is a primary treatment to remove as much of the cancer as possible. It may be followed by adjuvant therapies, like radiation or chemotherapy, to eliminate remaining cancer cells and reduce the chance of recurrence.
Radiation therapy uses high-energy beams to destroy cancer cells. Other treatments are systemic, meaning they travel through the bloodstream to affect cells throughout the body. This is important for cancers that have spread and includes:
- Chemotherapy, which uses drugs to kill rapidly dividing cells
- Targeted therapy, which focuses on specific molecules within cancer cells
- Immunotherapy, which helps the body’s own immune system fight the cancer