Cancer begins when damaged or abnormal cells start growing when they should not.
Unlike healthy cells, cancer cells can keep multiplying, push into nearby tissue, and sometimes travel to distant parts of the body.
How quickly this happens can be very different from one person and one cancer to another.
Some cancers are known for moving fast. Small-cell lung cancer, pancreatic cancer, and certain aggressive brain tumors can grow or spread over weeks or months.
In these cases, waiting too long to investigate symptoms may allow the disease to become much harder to treat.
Pancreatic cancer is especially difficult because it can develop with few obvious warning signs. Research published in The Lancet Oncology has examined how pancreatic cancer develops and spreads, helping scientists understand why many cases are already advanced when they are discovered. The pancreas also sits deep inside the abdomen, so small tumors are not easy to notice during a routine examination.
Other cancers may behave very differently. Many prostate cancers grow so slowly that they may never cause serious illness during a person’s lifetime. Research published in The New England Journal of Medicine has shown that carefully selected men with localized prostate cancer can sometimes be monitored rather than treated immediately.
This approach is called active surveillance. Doctors regularly check the cancer with tests and examinations and recommend treatment if there are signs that it is becoming more active. It does not mean ignoring cancer, and it is only suitable for certain patients.
Some breast cancers can also grow relatively slowly, particularly cancers that depend on hormones such as estrogen for their growth. When found early, many of these cancers can be treated successfully. However, a slow-growing cancer can still become dangerous if it eventually invades nearby tissue or spreads elsewhere.
Doctors often study cancer growth by looking at a tumor’s “doubling time.” This is the amount of time it takes for a tumor to become roughly twice as large. Research published in Radiology has found very large differences in the growth rates of lung cancers, with some tumors doubling much faster than others.
These differences happen because cancer is not a single disease. There are hundreds of cancer types and subtypes, and even two tumors that begin in the same organ may have different genetic changes and growth patterns. A person’s age, general health, tumor biology, and response of the immune system can also influence what happens.
When cancer spreads to another part of the body, doctors call it metastasis. Cancer cells can break away from the original tumor, enter blood vessels or the lymph system, and establish new tumors in organs such as the liver, lungs, bones, or brain. Metastatic cancer is usually more difficult to control than cancer that remains in its original location.
This is why finding cancer early can matter so much. Many cancers have much better treatment outcomes when they are discovered before they have spread, although survival varies greatly by cancer type and individual circumstances. Screening programs for cancers such as breast, bowel, and cervical cancer are designed to find disease or abnormal changes before serious symptoms develop.
Untreated cancer does not always worsen at the same speed, but it generally does not simply disappear. An aggressive cancer may change dramatically in a short period, while a slow cancer may take years to cause major problems. No one can reliably judge the speed of a suspected cancer from symptoms alone.
If cancer is suspected or has already been diagnosed, medical advice should not be delayed because the cancer seems small or symptoms seem mild. Doctors can use scans, laboratory tests, biopsies, and other information to estimate how aggressive a cancer may be and whether treatment is needed quickly.
Early assessment gives patients the best chance to understand their options and make informed decisions.
If you care about cancer, please read studies that low-carb diet could increase overall cancer risk, and new way to increase the longevity of cancer survivors.
For more health information, please see recent studies about how to fight cancer with these anti-cancer superfoods, and results showing daily vitamin D3 supplementation may reduce cancer death risk.
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