Cancer can develop slowly over many years within the body, sometimes without a person knowing it. The cancer may only be at an advanced stage when a person notices symptoms.

However, doctors can diagnose many cancers early, even before symptoms develop.

This article explores how long a person can have cancer without knowing and the types of cancer that may have the potential to go undetected.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

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

Conversely, asymptomatic cancers may not trigger noticeable symptoms, even as they progress. In these instances, doctors may detect cancer incidentally 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.

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: This 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: In the early stages, lung cancer does not often produce significant symptoms. Symptoms may link to other respiratory issues, such as asthma, leading to a delayed diagnosis.
  • Ovarian cancer: This cancer is known for its silent nature. Symptoms may relate to other conditions, leading to delayed diagnosis and more challenging treatment.
  • Thyroid cancer: Some people may have a lump or pain in their throat, but many are asymptomatic.
  • Kidney cancer: Early stage kidney cancer may not cause symptoms, and doctors may detect it incidentally during imaging studies for unrelated reasons.
  • Colorectal cancer: Bowel cancer causes vague symptoms and can be hard to detect in the initial stages.
  • Liver cancer: Early stage liver cancer may not cause noticeable symptoms. A doctor may detect it incidentally during routine medical tests or when investigating unrelated conditions.

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

Screening programs are vital for detecting cancers at earlier stages when treatment options are more effective. By participating in these programs and monitoring for subtle signs or symptoms, individuals can contribute to the early detection and improved outcomes of various cancers.

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, other symptoms may include:

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. A person should talk with a doctor about any bothersome symptoms they experience, regardless of the possible cause.

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.

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.