A tumor refers to an abnormal mass of tissue that forms when cells grow and divide excessively or fail to die as they should. This uncontrolled growth can occur almost anywhere in the body, ranging in size from a small nodule to a large mass. The term “tumor” itself is broad and encompasses various types of growths, some of which are more concerning than others.
What is a Tumor?
Our bodies are constantly producing new cells to replace old or damaged ones, a process that is typically well-regulated. When this orderly process breaks down, and cells begin to grow and multiply without proper control, they can accumulate and form a lump of tissue known as a tumor. Tumors develop from an overgrowth of cells, where new cells form even when the body does not need them, or old cells do not die off as expected.
Distinguishing Malignant and Benign Growths
Understanding the nature of a tumor involves distinguishing between benign (non-cancerous) and malignant (cancerous) growths. Benign tumors are generally localized and do not spread to other parts of the body. These growths typically grow slowly and tend to have a regular, smooth shape, often encased in a capsule. While they can sometimes cause problems if they press on nerves or organs, they are usually not life-threatening and do not typically return after removal.
In contrast, malignant tumors are cancerous and aggressive. They can invade surrounding tissues and grow rapidly. A defining characteristic of malignant tumors is their potential to metastasize, meaning cancer cells can break away from the original tumor and travel through the bloodstream or lymphatic system to form new tumors in distant parts of the body. These new tumors are called metastases. The ability of malignant cells to invade and spread often requires more complex and varied treatments compared to benign growths.
How Tumors Form
Tumor formation involves genetic mutations in a cell’s DNA. Our cells contain genes that provide instructions for their behavior, including when to grow, divide, or die. When mutations occur in these genes, they can disrupt normal cell cycle control.
These mutations can activate growth-promoting genes, known as proto-oncogenes, turning them into oncogenes that cause uncontrolled cell growth. Conversely, mutations can deactivate tumor suppressor genes, which normally regulate cell growth and division or repair damaged DNA. When these suppressor genes are faulty, cells divide uncontrollably and accumulate further genetic damage. Mutations can happen by chance during cell division, be caused by environmental exposures like carcinogens, or sometimes be inherited, leading to an increased likelihood of tumor development.
How Tumors Are Identified
Medical professionals use various methods to detect and diagnose tumors. Imaging techniques are often the first step in identifying suspicious masses or irregular tissues. These include X-rays, computed tomography (CT) scans, magnetic resonance imaging (MRI) scans, and ultrasound. While imaging can reveal the presence and characteristics of a growth, these methods alone cannot definitively determine if a tumor is benign or malignant.
For a conclusive diagnosis, a biopsy is necessary. This procedure involves removing a small sample of tissue or cells from the suspicious area for laboratory examination under a microscope. Biopsies can be performed using various methods, such as needle biopsies, where a thin needle is guided into the mass, sometimes with the aid of imaging, to collect cells. Tissue analysis from a biopsy determines the type of tumor and whether it is benign or malignant, guiding subsequent medical decisions. Early detection through these diagnostic methods leads to better outcomes.