Undetectable and asymptomatic cancers: Types and outlook

How long can a person have cancer without knowing?

The length of time a person can have cancer without knowing varies significantly. It depends on factors such as:

• the type of cancer
• its location
• how quickly it grows and spreads

Some cancers, such as carcinoid cancer, grow extremely slowly. Years or even decades may pass before they cause noticeable symptoms. During this time, the cancer may go undetected.

Cancer may also go undetected because of factors such as an individual’s overall health and medical conditions that may cause symptoms similar to cancer. Sometimes, a person may overlook or dismiss symptoms, attributing them to other causes.

Symptomatic vs. asymptomatic cancer

Symptomatic cancer refers to cancer that causes obvious symptoms, even in the early stages. Although the specific symptoms can vary depending on the type and location of cancer, they may include:

• pain
• fatigue
• fever
• unexplained weight loss
• abnormal lumps or growths
• bleeding or bruising that are abnormal

These symptoms are often due to other causes. However, if they do not go away or worsen with time, it could indicate cancer.

Conversely, asymptomatic cancers may not trigger noticeable symptoms, even as they progress. In these cases, doctors may detect cancer during routine medical checkups, screenings, or investigations for unrelated health concerns.

This highlights the importance of regular health assessments and screenings, as they can play a crucial role in detecting cancer at an early stage, even before symptoms develop.

Cancers that are more likely to go undetected 

Some types of cancer are more challenging to detect because they often present with subtle or nonspecific symptoms. These can make them easier to overlook or to attribute symptoms to other causes. They include:

• Pancreatic cancer: Pancreatic cancer often goes undetected until it reaches an advanced stage. This can be due to its location, deep within the abdomen, and the absence of noticeable early symptoms.
• Lung cancer: Lung cancer does not often produce significant symptoms until advanced or locally advanced stages. Symptoms may link to other respiratory issues, such as asthma, leading to a delayed diagnosis.
• Ovarian cancer: Only around 20% of cases of ovarian cancer have a diagnosis in early stages. Symptoms may not appear until later stages and be similar to those of other health conditions.
• Thyroid cancer: People may have a lump or pain in their throat during early stages of thyroid cancer. However, in many cases, doctors find this cancer during checkups and screening for other issues.
• Kidney cancer: Early stage kidney cancer may not cause symptoms. The position of kidneys in the body can also disguise signs of cancer during physical exams and there are currently no kidney cancer screening tests.
• Colorectal cancer: Colorectal cancer causes vague symptoms and can be hard to detect in the initial stages. Screening may help with an early diagnosis but typically does not start until age 45.
• Liver cancer: Early stage liver cancer may not cause noticeable symptoms. The ribs also cover most of the liver, which can hide lumps and tumors until they are very large.

Several of the above types of cancer do not have a sensitive or specific screening test available for people who do not have symptoms.

List of cancers that may be asymptomatic 

Other cancers that can be asymptomatic until the advanced stages include:

• Brain cancer: Subtle signs of a brain tumor can include persistent headaches, unexplained seizures, changes in vision, or cognitive and behavioral changes.
• Testicular cancer: Regular self-examination of the testicles is important for early detection of testicular cancer. Healthcare professionals may recommend monthly checks to find lumps or other symptoms.
• Breast cancer: Breast cancer may not cause a lump among other symptoms. Mammograms and breast self-examinations can help with the early detection of breast abnormalities.
• Prostate cancer: Screenings, such as prostate-specific antigen blood tests and digital rectal exams, can lead to an earlier diagnosis of prostate cancer in males.
• Skin cancer: Skin cancer, including melanoma, can be asymptomatic or exhibit subtle symptoms until the advanced stages. Regular skin self-examinations can help with early detection.

Screening programs can be vital for detecting cancers at earlier stages when treatment options are more effective.

Early symptoms to look out for

Early signs of cancer may be vague and subtle, such as extreme tiredness that does not ease with rest. Depending on the type of cancer, more common symptoms may include:

• swollen lymph nodes
• unexplained weight loss or gain
• loss of appetite
• nausea and vomiting
• abdominal pain
• unusual lumps or swelling
• persistent pain
• unusual bruising or bleeding
• changes in bowel or urinary habits
• persistent cough
• difficulty swallowing
• skin changes
• fever
• night sweats
• vision problems or hearing difficulties
• headaches

When to contact a doctor

If a person experiences new or worsening health issues or symptoms, they should consult their doctor.

Many medical conditions unrelated to cancer can cause worrying symptoms. Regardless of the possible cause, people should talk with a doctor about any bothersome symptoms they experience.

Anyone with a family history of cancer should discuss their screening and preventive options with a doctor. Early detection and treatment play a crucial role in improving cancer outcomes.

Summary

There is no one answer to how long someone can have cancer without knowing. It depends on various factors, including the type of cancer, its growth rate, individual health conditions, and screening practices.

While some cancers may cause clear signs and symptoms, others can be asymptomatic, especially in the early stages. Examples of potentially asymptomatic cancers include lung, prostate, pancreatic, and brain cancers.

People should have regular checkups and screenings and undertake self-examinations to identify potential cancer-related concerns as early as possible.