What's in this article?
Malignant tumors are cancerous tumors – they tend to become progressively worse, and can potentially result in death. Unlike benign tumors, malignant ones grow fast, they are ambitious, they seek out new territory, and they spread (metastasize).
The abnormal cells that form a malignant tumor multiply at a faster rate. Experts say that there is no clear dividing line between cancerous, precancerous and non-cancerous tumors sometimes determining which is which may be arbitrary, especially if the tumor is in the middle of the spectrum. Some benign tumors eventually become premalignant, and then malignant.
Metastasis – malignant tumors invade nearby cells, and then the cells near those, and spread. Some cells can break off from the tumor and spread to various parts of the body through the bloodstream or the lymphatic system, and establish themselves anywhere in the body, and form new malignant tumors. Metastasis is the process by which cancer cells spread from their primary site to distant locations in the human body. For example, a patient may have started off with melanoma (skin cancer) which metastasized in their brain.
The cancer cells that metastasize are the same as the original ones. If a lung cancer spreads to the liver, those cancer cells that grow in the liver are lung cancer cells which have acquired the ability to invade other organs.
There are different types of tumors, which are made up of specific types of cancer cells:
- Carcinoma – these tumors are derived from the skin or tissues that line body organs (epithelial cells). Carcinomas can be, for example, of the stomach, prostate, pancreas, lung, liver, colon or breast. Many of the most common tumors are of this type, especially among older patients.
- Sarcoma – these are tumors that start off in connective tissue, such as cartilage, bones, fat and nerves. They originate in the mesenchymal cells outside the bone marrow. The majority of sarcoma tumors are malignant. They are called after the cell, tissue or structure they arise from, for example fibrosarcoma, liposarcoma, angiosarcoma, chondrosarcoma, and osteosarcoma.
- Lymphoma/Leukemia – cancer arises from the blood forming (hematopoietic) cells that originate in the marrow and generally mature in the blood or lymph nodes. Leukemia accounts for 30% of childhood cancers. Leukemia is thought to be the only cancer where tumors are not formed.
- Germ cell tumor – these are tumors that arise from a germ cell, pluripotent cells (cells than can turn into any kind of cell). Germ cell tumors most commonly present in the ovary (dysgerminoma) or testicle (seminoma). The majority of testicular tumors are germ cell ones. Less commonly, germ cell tumors may also appear in the brain, abdomen or chest.
- Blastoma – tumors derived from embryonic tissue or immature “precursor” cells. These types of tumors are more common in children than adults. Blastoma is often the root word used in longer ones that describe tumors, for example, medulloblastoma and glioblastoma are kinds of brain tumors, retinoblastoma is a tumor in the retina of the eye, osteoblastoma is a type of bone tumor, while a neuroblastoma is a tumor found in children of neural origin.
What is the difference between a benign and malignant tumour?
Benign tumors aren’t cancerous. They can often be removed, and, in most cases, they do not come back. Cells in benign tumours do not spread to other parts of the body.
Malignant tumors are cancerous and are made up of cells that grow out of control. Cells in these tumours can invade nearby tissues and spread to other parts of the body. Sometimes cells move away from the original (primary) cancer site and spread to other organs and bones where they can continue to grow and form another tumour at that site. This is known as metastasis or secondary cancer. Metastases keep the name of the original cancer location. e.g. pancreatic cancer that has spread to the liver is still called pancreatic cancer.
Signs and symptoms of Malignant tumors
The symptoms of a malignant brain tumour depend on how big it is and where it is in the brain.
Common symptoms include:
- severe, persistent headaches
- seizures (fits)
- persistent nausea, vomiting and drowsiness
- mental or behavioural changes, such as memory problems or changes in personality
- progressive weakness or paralysis on one side of the body, vision problems, or speech problems
See your GP if you have persistent symptoms of a brain tumour. While it’s unlikely to be a tumour, it’s best to be sure by getting a proper diagnosis.
Who is affected
Brain tumours can affect people of any age, including children, although they tend to be more common in older adults.
Around 5,000 people are diagnosed with a primary malignant brain tumour in the UK each year. Many others are diagnosed with secondary tumours.
The exact cause of primary malignant brain tumours is unknown, although it’s thought that certain genetic conditions and previous radiotherapy treatment to the head may increase the risk of one developing.
What are Treatment options?
Optimal treatment often demands the combined skills of an exceptional surgeon, pathologist, radiologist, radiotherapist, medical oncologist, and sometimes a plastic surgeon.
In the past 15 years, important improvements have been made in the treatment of malignant soft tissue tumors.
The addition of chemotherapy for the highest-grade tumors reduces the rate at which high-grade tumors return and may improve the rate of cure. The use of specialized radiation therapy techniques has significantly reduced the likelihood of tumors coming back at the site where they have been removed. Often, depending on the type of tumor, preoperative radiation therapy or chemotherapy (or a combination of the two) may be used to make some of these tumors more easily resected with adequate margins.
Radiation therapy, in combination with improved techniques for surgical removal and improved methods for functional reconstruction, now allows 90-95% of patients with these aggressive tumors to be treated using “limb salvage” (Create link to limb salvage section) techniques (i.e. without amputation).