Overview
Oncology is the branch of medicine that deals with cancer. It includes preventing cancer when possible, finding it, understanding how far it has spread, choosing treatment, and monitoring health after treatment. Because cancer affects many parts of the body and can change over time, oncology care is often provided by a team.
Key Symptoms
Cancer symptoms vary widely depending on the type and location, and some cancers may not cause symptoms early on. Warning signs can include a new lump, unexplained weight loss, unusual bleeding, a sore that does not heal, ongoing pain, a lasting cough, changes in bowel or bladder habits, or unusual tiredness. These symptoms can also happen with many non-cancer conditions, so medical evaluation is important.
Causes and Risk Factors
Cancer develops when cells grow and divide in an uncontrolled way. Risk can be affected by tobacco use, alcohol use, certain infections, radiation exposure, some workplace exposures, family history, inherited genetic changes, age, and lifestyle factors such as diet, body weight, and physical activity. Sometimes cancer happens without a clear cause.
Who Is Affected
Cancer can affect people of any age, sex, or background, although many cancers become more common with older age. Some cancers are more common in certain populations because of genetics, environmental exposures, infections, or access to screening and healthcare. Children can also develop cancer, but pediatric cancers often differ from cancers seen in adults.
Prevention
Not all cancers can be prevented, but some risks can be lowered. Avoiding tobacco, limiting alcohol, protecting skin from too much sun, staying physically active, maintaining a healthy body weight, and getting recommended vaccines such as HPV and hepatitis B can help reduce risk. Taking part in recommended screening programs can also help find some cancers earlier.
Diagnosis and Tests
Oncology diagnosis often begins with a medical history, physical examination, imaging tests, blood tests, and a biopsy, which means taking a tissue sample to look at under a microscope. Doctors may also use molecular or genetic testing on the tumor to better understand the cancer and guide treatment choices. Staging tests help show whether cancer is limited to one area or has spread.
Treatment Categories
Cancer treatment depends on the cancer type, stage, overall health, and the person's goals and preferences. Common treatment categories include surgery, radiation therapy, chemotherapy, targeted therapy, immunotherapy, hormone therapy, stem cell transplant, and supportive or palliative care. Some people receive one treatment, while others receive a combination over time.
Living With It
Living with cancer can affect physical health, emotions, work, finances, relationships, and daily routines. Follow-up care may include checking for treatment response, watching for recurrence, managing side effects, and supporting mental health. Rehabilitation, pain management, social support, and palliative care can all be part of oncology care.
When to Seek Medical Care
Seek medical care if you notice ongoing or unexplained symptoms such as a new lump, unexplained bleeding, major weight loss, persistent pain, changes in a mole, or a cough that does not go away. People with a history of cancer should also contact their care team about new symptoms, treatment side effects, or concerns about recurrence. Keep up with recommended screening and follow-up appointments.
When It May Be an Emergency
Urgent medical help may be needed for severe trouble breathing, chest pain, confusion, seizures, heavy bleeding, sudden weakness, high fever during cancer treatment, or severe dehydration from vomiting or diarrhea. Some cancer treatments can lower the body's ability to fight infection, making fever or signs of infection especially important. If symptoms are severe, sudden, or rapidly worsening, seek emergency care right away.