Brain cancer can interfere with normal brain functions such as speech, movement, thoughts, feelings, memory, vision, and hearing. It is a disease of the brain in which abnormal, cancerous cells grow in the brain tissues. Typically, brain cancer is a developed form of a brain tumour. Primary brain cancer or a brain tumour develops from cells within the brain.

However, all brain tumours are not brain cancer. But one thing to note is that even benign tumour can cause serious problems by increasing intracranial pressure or obstruct vascular structures or cerebrospinal fluid flow in the brain.

Different types of cells in the brain such as gliomas, meningiomas, pituitary adenomas, vestibular schwannomas, and primitive neuroectodermal (medulloblastomas) can become cancerous. Gliomas have several subtypes, which include astrocytomas, oligodendrogliomas, ependymomas, and choroid plexus papillomas.

Types of Brain Cancers

There are two types of brain cancer, including:

• Primary brain cancers: Primary brain cancers result when cancer cells develop in the tissues of the brain itself. Primary brain cancer cells may travel short distances within the brain but generally would not travel outside of the brain itself.
• Secondary brain cancers: Secondary brain cancer is called metastatic brain cancer. It occurs when cancer develops elsewhere in the body and spreads to the brain. Primary cancer tissues can spread via direct extension, or through the lymphatic system or through the bloodstream.

Metastatic cancer in the brain is more common than primary brain cancer. They are usually named after the tissue or organ where cancer first develops. Metastatic lung or breast cancer in the brain is the most commonly found brain cancers.

Brain Cancer Causes

The exact brain cancer cause is still unknown. However, its occurrence has been linked to several risk factors, including the following:

• Exposure to radiation
• HIV infection
• Inherited abnormality
• Smoking
• Exposure to environmental toxins
• Exposure to chemical toxins, especially those used in rubber industry and oil refinery

Brain Cancer Symptoms

Some types of brain cancers such as meningeal and pituitary gland may produce few or no symptoms. Some of the brain cancer symptoms typically experienced by patients include:

• Difficulty walking, seizures, dizziness and vertigo
• Extreme fatigue and muscle weakness
• Severe headaches and blurry vision
• Sleepiness, nausea, and vomiting
• Reduction in mental alertness, capacity or memory
• Difficulty in speaking, impaired voice or inability to speak
• Personality changes and hallucination
• Weakness on one side of the body and coordination problems
• Reduced touch sensation

Lung cancer is an uncontrolled growth of cells that start off in the lungs. Usually, lung cancer starts in the cells that line the air passages. Instead of developing into healthy lung tissue, the cells divide rapidly and form tumours.

Lung cancer can grow and spread beyond the lung to reach other parts of the body through metastasis. Lung cancers can begin in any part of the lung, but 90 percent of lung cancers begin in the epithelial cells, which are the cells lining the larger and smaller airways also known as bronchi and bronchioles.

This is the reason why lung cancers are sometimes called bronchogenic cancers or bronchogenic carcinomas. Lung cancer is the most common cancer in the world, among both men and women. It is the leading cause of cancer deaths worldwide.

Lung Cancer: Causes and Risk Factors

Long-term smoking is the main cause of lung cancer. After smoking, genetic factors and exposure to radon gas, asbestos, second-hand smoke or other forms of air pollution can also increase the risk of lung cancer.

Types of Lung Cancer

There are two major types of lung cancers, based on the appearance of lung cancer cells under the microscope:

• Non-small cell lung cancer (NSCLC): It is an umbrella term for several types of lung cancers that behave in a similar way, such as squamous cell carcinoma, adenocarcinoma, and large cell carcinoma.
• Small cell lung cancer (SCLC): This type of lung cancer occurs mostly in heavy smokers and it is less common than non-small cell lung cancer. 
  
  

Lung Cancer Stages

It is necessary to determine the stage of lung cancer by finding out how far cancer has spread, before initiating treatment of lung cancer.
The following are the four lung cancer stages of NSCLC:

• Stage 1 lung cancer: Cancer is restricted to the lung
• Stage 2 lung cancer: Cancer has spread to the nearby lymph nodes
• Stage 3 lung cancer: (3a) Cancer is in the lung and the lymph nodes located on the same side  (3b) Cancer is in the lung and has spread to lymph nodes on the opposite side
• Stage 4 lung cancer: Cancer has spread to both the lungs and other organs and surrounding tissues
  
  

The following are the two lung cancer stages of SCLC:

• Limited stage: Cancer is present in just one lung and lymph nodes on the same side of cancer.
• Extensive stage: Cancer has spread throughout the lung or both the lungs, to the lymph nodes on the opposite side, to the bone marrow, and to the distant organs.

After the determination of stage, treatment of lung cancer starts with choosing the best suitable option for the patient. However, there is usually no single treatment for lung cancer. So the patient often receives a combination of therapies and palliative care. 

Lung Cancer Symptoms

Lung cancer symptoms may vary, depending upon where and how widespread the tumour is. A person with lung cancer may have following lung cancer symptoms:

• A persistent or chronic coughing
• Pain in chest, shoulder or back
• Difficulty in breathing and shortness of breath
• Hoarseness or change of voice
• Chronic bronchitis, pneumonia or respiratory infections
• Blood in the sputum and cough

Stage 3 lung cancer symptoms include the following:

• Wheezing
• General pain in the chest or when breathing
• Persistent cough with or without blood
• Altered voice
• Loss of appetite
• Unplanned weight loss
• Fever, headache, weakness, and bone pain
• Difficulty swallowing

Oral cancer, commonly referred to as mouth cancer or throat cancer, is an uncontrollable growth of cells in the oral cavity. It refers to cancer that develops in any of the parts that make up the mouth. It can include cancer of the lips, tongue, cheeks, the floor of the mouth, pharynx (throat), hard and soft palate and either of the sinuses. Mouth and oropharyngeal cancer can be life-threatening, but it could be prevented if the cancer is diagnosed early enough.

What Causes Oral Cancer?

Oral cancer is a result of a mutation in the DNA of the cells in the mouth. There are certain identified risk factors for mouth cancer that predisposes a person to oral cancer.

Some of the oral cancer risk factors include:

• Smoking: Smoking tobacco (cigarettes, cigars, and pipes) contains nitrosamines and other chemicals that are known to cause cancer. People who are exposed to passive smoking also experience a small increase in their risk of oral cancer.  
• Chewing tobacco: Use of any type of tobacco is one of the main reasons behind oral cancer. Chewing tobacco is not a safe alternative to cigarettes. It is a popular habit in parts of Asia and in some immigrant groups in Europe, North America, and Australia. The harmful substances in tobacco and betel can cause oral cancer.
• Alcohol consumption: Drinking excessive alcohol increases the risk of oral cancer. Using tobacco and alcohol both pose a much greater risk than using either of the substance alone.
• Poor diet: Lack of vitamins and minerals, such as iron or folic acid in the diet, can lead to a breakdown in the oral mucosa and this can make people more prone to oral cancer. People should eat plenty of proteins, vitamins, and minerals to decrease the risk of oral cancer. Fresh fruits and vegetables contain a lot of antioxidants, vitamins and other substances that help prevent damage to body cells.
• A family history of disease: There is a slightly higher risk of getting oral cancer in people who have a close relative who once had oral cancer.
• Human Papilloma Virus (HPV): HPV can contribute to some types of cancers, but it does not mean that people get these cancers like an infection. HPV can be passed on to another individual during a sexual contact, but for a majority of people, the virus is harmless and does not cause any trouble. Only a very small percentage of people with HPV end up developing oral cancer.
  
  

Oral Cancer Symptoms

There are some typical signs of mouth cancer that a majority of patients experience. Make sure to visit your doctor or dentist in case you experience any of the following signs of mouth cancer:

• Pain and discomfort in the mouth: Ongoing pain or discomfort from a long time in the mouth is the one of the most symptoms.
• Ulcers and sore: Bleeding ulcer or sore, which is not healing for more than two weeks can be a symptom of oral cancer.
• Unexplained bleeding: Unexplained bleeding in the mouth can be an alarming indication of oral cancer.
• Numbness and lost sensation: Numbness, loss of feeling or tenderness in any area of the mouth, or neck can be a symptom.
• White or red patches: Any abnormal looking patches in the mouth or throat could be a sign of cancer or precancerous changes. Although, a fungal infection called thrush can also be the reason for white or red patches.
• Difficulty in swallowing: You may feel difficulty in chewing and swallowing and feel like your food is sticking in your throat. Feeling difficulty in speaking or moving the jaw and tongue can be one of the most important throat cancer symptoms.
• Weight loss: Dramatic weight loss without any reason can also be a symptom.

Stomach cancer, also known as gastric cancer, is the fifth most common cancer worldwide. This disease is a result of the growth of cancerous and malignant cells in the inner lining of the stomach.

Stomach cancer does not grow overnight as this disease usually grows slowly over many years. Some pre-cancerous changes take place before true cancer actually develops. But these early changes rarely result in any symptoms and therefore, often go undetected in the early stage when it is most easy to treat it.

Gastric cancer can grow through the wall of the stomach and invade nearby organs. It can easily spread to the lymph vessels and lymph nodes. In an advanced stage, it can travel through the bloodstream and spread or metastasize to organs such as the liver, lungs, and bones. Usually, people diagnosed with stomach cancer have either experienced metastasis already or eventually develop it.

Types of Stomach Cancer

Stomach cancer should not be confused with other cancers in the abdomen or esophageal cancer. Some other cancer can also occur in the abdomen, including cancer of the large and small intestine, liver or pancreas. These cancers may have different symptoms, outlook, and options for treatment.

Some of the common types of gastric cancer include:

• Adenocarcinoma: It is the most common form of stomach cancer and about 90 to 95 percent of stomach cancers are This form of cancer develops from the cells that form the innermost lining (mucosa) of the stomach.
• Lymphoma: This is a rare form of stomach cancer and only about four percent of stomach cancers are lymphomas. These are cancers of the immune system tissue, sometimes found in the wall of the stomach.
• Gastrointestinal stromal tumor (GIST): It is a rare kind of tumor that starts in very early forms of cells in the wall of the stomach calledinterstitial cells of Cajal. GISTs can be found anywhere in the digestive tract.
• Carcinoid tumour: It is also a rare form of stomach cancer and about three percent of stomach cancers are carcinoid tumors. Carcinoid tumors start in cells of the stomach that produced hormones.

Some other types of stomach cancers include squamous and small cell carcinoma and leiomyosarcoma. These cancers are very rare.

Stomach Cancer Causes

There is no single, definite cause behind stomach cancer. However, several stomach cancer risk factors have been identified that could potentially lead to the formation to a tumor in the stomach. Some of these stomach cancer causes or risk factors include:

• Inflammation of the gut called gastritis
• Infection with common bacteria called Helicobacter pylori
• Long-lasting anaemia
• Growth in stomach called polyps
• Smoking
• Obesity
• Excessive consumption of smoked, pickled or salty foods
• A-type blood group
• Epstein-Barr virus infection
• Certain genes (family history of disease)

Stomach Cancer Symptoms

There can be several early stomach cancer symptoms. However, the signs of stomach cancer could be present because of some other underlying condition as well. Unfortunately, this is the main reason why it is difficult to make stomach cancer diagnosis at an early stage.

Some of the early stomach cancer symptoms may include:

• Heartburn
• Regular indigestion
• Slight nausea
• Loss of appetite
• Frequent burping
• Feeling bloated

But just experiencing indigestion or heartburn after a meal does not really mean that you have cancer. Although, if you experience these symptoms a lot, talk to your doctor, who can decide whether to conduct further tests or not.

As advanced gastric cancer grow, you may experience more serious signs of stomach cancer, including the following:

• Frequent stomach ache or pain in the sternum
• Frequent heartburns
• Vomiting containing blood
• Dysphagia (swallowing difficulties)
• Loss of appetite, accompanied by sudden weight loss
• Blood in stools
• Excessive fatigue
• Yellowish eyes or skin