Early Signs of Insidious Cancers That Are Often Overlooked

Cancer refers to a diverse, complex group of diseases. They can grow and develop silently in the body, often without obvious symptoms. This can make early detection and diagnosis difficult.

However, informed cooperation between patients and doctors can enable early cancer detection, even before symptoms appear.

How Long Do You Have Cancer Before Diagnosis?

The time between cancer starting to develop in the body and being noticed varies according to its type, location, and rate of growth and spread.

Whether this period is longer or shorter may depend on:

• Cancer type
• The cancer's site and location
• How quickly it grows and spreads

It is difficult to give an exact figure for the time between a cancer cell forming and a visible tumor developing, for example one measuring 5 mm in diameter. This may take months or years. We know, however, that the time from cancer-cell formation to a tumor reaching a noticeable size can vary greatly according to cancer type, growth rate, and a range of other factors.

For example, some types, such as carcinoid tumors, can grow extremely slowly and insidiously, taking years or even decades to cause obvious symptoms. During that time, the cancer may be difficult to detect.

Another example is lung cancer. Lung tumors have been found, on average, to double in size within four to five months. This provides an important indication of how quickly lung cancer can progress. However, the interval varies across lung cancer subtypes. One study found that non-small cell lung cancer (NSCLC) tumors took an average of 191 days to double in size. This indicates that NSCLC grows substantially more slowly than small cell lung tumors. It also notes that tumors in smokers grow faster than those in people who have never smoked or who have quit.

Failure to detect cancer early may relate to a person's overall health. Symptoms resembling those of other diseases can also lead people to consider those conditions before cancer. In such situations, rather than thinking of cancer, people try to relieve symptoms based on the condition they initially suspect.

Symptomatic and Asymptomatic Cancers

Symptomatic cancers cause noticeable symptoms even in their early stages. Although common cancer symptoms vary according to the cancer's type and location, they may mainly include:

• Pain
• Exhaustion and fatigue
• Unexplained weight loss
• Abnormal lumps, bumps, or growths in the body

By contrast, asymptomatic cancers may not cause noticeable symptoms even at very advanced stages. They may be detected during routine checkups or screening, or incidentally when a patient attends hospital for another reason. To detect these cancers at an early stage, when more treatment options are available, routine cancer screening is very important. In particular, people with a family history of cancer need screening at regular intervals.

Some cancers are also difficult to detect because they cause milder symptoms rather than the usual or common signs of cancer. These symptoms may be overlooked or attributed to other causes.

Cancers that can generally be described as insidious include:

• Pancreatic cancer: This cancer often goes unnoticed until it reaches advanced stages because it lies deep in the abdomen and does not cause noticeable early symptoms.
• Lung cancer: Early-stage lung cancer often causes no significant symptoms. Symptoms may be attributed to other respiratory problems, such as asthma, delaying diagnosis.
• Ovarian cancer: This cancer is known for its silent nature. Symptoms may be linked to other conditions, leading to delayed diagnosis and more difficult treatment.
• Thyroid cancer: Although some cases cause a lump or pain in the throat, most thyroid cancers cause no symptoms.
• Kidney cancer: Early-stage kidney cancer may cause no symptoms. In some cases, it is found incidentally on medical imaging performed for other complaints.
• Colorectal cancer: The symptoms of large bowel cancer may also be attributed to other causes, making early detection difficult.
• Liver cancer: Early signs of liver cancer may be overlooked. It may be found incidentally during routine screening or on medical imaging requested for other reasons.

Cancers that may cause no symptoms until advanced stages can include:

• Brain cancer: Uncommon signs of a brain tumor may include persistent headaches, unexplained seizures, visual changes, or cognitive and behavioral changes.
• Testicular cancer: Regular testicular self-examination is important for early diagnosis. During these examinations, people should look for abnormal lumps, swelling, or changes and note whether they feel any pain.
• Breast cancer: In some cases, breast cancer may cause no abnormal lump or obvious symptom. People therefore need to perform breast self-examinations and watch for changes, which can be very important for early diagnosis if a problem arises.
• Prostate cancer: Men should take time to understand their risk factors and undergo recommended screening, such as prostate-specific antigen blood tests and digital rectal examinations.
• Skin cancer: Certain skin cancers, including melanoma, may be asymptomatic. They may cause subtle, overlooked signs until advanced stages. During regular skin self-examinations, people should watch for changes in the size, shape, or color of moles. They should also look for any new mole, spot, or tissue change.

The most important precaution against these insidious cancers, which cause no symptoms or only subtle signs that may be overlooked or attributed to another disease, is to be aware of your body, take new and persistent symptoms seriously, and see a doctor for an examination. Regular screening at healthcare facilities is also very important. In particular, people with a family history of cancer need these potentially lifesaving checks to support early diagnosis. Early diagnosis can save lives in many cases, provide more treatment options, and help make treatment easier to tolerate. People should not miss or postpone routine screening if they are to benefit from opportunities for early diagnosis of a possible cancer.

Early Cancer Symptoms That Are Often Overlooked

Cancer can cause different symptoms depending on its type, location, and a person's health. However, some cancers cause no symptoms until advanced stages, or cause only very mild symptoms that may be ignored. These may also be attributed to other health problems, leaving the possibility of cancer in the background.

Subtle, mild, and easily overlooked signs of cancer may include:

• Swollen lymph nodes
• Unexplained weight loss or weight gain
• Nausea and vomiting
• Abdominal pain
• Abnormal lumps, bumps, or swelling
• Persistent pain
• Unusual bruising or bleeding
• Changes in bowel or urinary habits
• A persistent cough
• Difficulty swallowing
• Skin changes
• Fever
• Night sweats
• Vision or hearing problems
• Headache

New complaints, symptoms, and signs lasting longer than 2-4 weeks must be taken seriously and assessed by a doctor.

When Should You See a Doctor?

Anyone experiencing new or worsening health problems is advised to consult a specialist.

Many medical conditions unrelated to cancer can cause concern. Expert assessment is therefore important for any troubling problem, whatever its cause.

Everyone with a family history of cancer should consult a specialist for screening and prevention assessments. Early diagnosis and treatment play a very important role in all conditions that cancer may cause.

Why Are Cancers Described as Insidious? A Summary

Cancer may develop silently and unnoticed, making early detection and diagnosis difficult. The interval between cancer developing and symptoms appearing depends on many factors, but some cancers may cause no symptoms for years or even decades.

Routine health screening is important for detecting early-stage cancers. Some cancers also cause subtle symptoms resembling other diseases, making self-examination and regular health checkups important. Symptoms may differ according to cancer type, location, and a person's health. Specialist advice is recommended for suspicious findings or worsening health problems. In particular, people with a family history of cancer should consult specialists for screening and prevention assessments.

Early diagnosis and treatment are critical in cancer-related conditions.