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Cancer Screening Tests - An Overview

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Cancer screening is highly valuable for early detection, treatment planning, and cancer prevention. Read this article to know more about cancer screening.

Written by

Dr. Ramji. R. K

Medically reviewed by

Dr. Rajesh Gulati

Published At September 28, 2022
Reviewed AtSeptember 28, 2022


History has seen many deadly cancers that reported a large number of deaths. The high mortality rate in cancers is mainly due to cancer undetected at an early stage. Early detection can help find out cancer before its symptomatic stage. It also helps reduce the risk of cancer development and treat it more effectively. Scientists discovered different screening tests that help in the early detection of cancer. Different screening tests are used in detecting different cancers.

What Is a Screening Test?

Screening tests detect any disease or health disorder before it exhibits any signs and symptoms in individuals. It is a preventive measure that helps in the early detection of any health disorders or reduces the risk of developing them.

Cancer screening tests aim to detect cancer early and help treat it more effectively. Scientific evidence has proven that cancer screening tests play a vital role in decreasing the mortality rate in cancer cases. Different cancer screening tests are used for detecting different cancers.

The “Pap test” was the first cancer screening test that was widely used. It was developed by George Papanicolaou. Initially, it was used as a research tool for understanding the menstrual cycle. But surprisingly, Papanicolaou found out its role in detecting cervical cancer. The Pap test was not widely accepted initially, but later in the 1960s, the American cancer society later promoted the test. From then onwards, it has been used widely as a cancer screening tool. Mortality rates in cervical cancers decreased gradually by more than 50 % due to its early detection by Pap test. In the late 1960s, other screening methods like mammography were developed. Mammograms were found to be more reliable in breast cancer screening.

What Is the Difference Between Screening Test and Diagnostic Test?

Screening tests are entirely different from diagnostic tests. Screening tests aim to early detection of the disease or identify the risk factors in developing the condition. At the same time, diagnostic tests help find the presence or absence of disease (diagnosis). Screening tests are simple and more affordable than diagnostic tests.

What Are the Different Screening Tests Used in Cancer Screening?

There are many cancer screening tests used. Cancer screening tests are only done under the advice of doctors. Do consult your doctor before having a cancer screening. Let us see in detail the different screening tests used in different cancers.

1. Lung Cancer Screening: Lung cancer screening is carried out using a “low-dose helical CT (computed tomography) scan” or “spiral CT scan.” It gives out 3-dimensional images of a tumor or abnormalities. These screening tests are recommended based on the age and smoking habit of the person. Screening tests in non-smokers (non high-risk individuals) are not usually recommended. But if recommended, it may be suggested to have a low-dose CT scan at an interval between five to ten years. Low-dose helical CT scans are safe and should be carried out only if your doctor suggests you. These screening tests have reduced the mortality rate in lung cancer cases through early detection and treating it better.

2. Breast Cancer Screening: Breast cancer screening includes:

  • Mammogram: It is an X-ray of the breast that helps in the early detection of breast cancer. A screening mammogram is a regular breast X-ray as part of a general checkup. Screening mammograms are different from diagnostic mammograms. It is done in women with no breast cancer symptoms but at a higher risk. Diagnostic mammograms are used in women who experience any symptoms of breast cancer or are carried out after an abnormal screening. Screening mammograms is done annually only if your doctor recommends doing it. Due to the early detection of breast cancer by screening, the mortality rate in breast cancer is highly reduced.

  • Breast MRI: Breast MRI (magnetic resonance imaging) as a screening tool is not used regularly. But it helps detect breast cancer in women who are at higher risk. Other screening tests for breast cancer include a clinical breast examination and breast self-examination. In clinical breast examination, your healthcare provider will look for any unusual changes in breast shape, size, and changes in the skin around the breast and nipples. In breast self-examination, a woman self-examines her breast to find any unusual changes. If any changes are noticed, then she should consult a doctor.

3.Cervical Cancer Screening:

  • Pap Test: Pap tests help in the early detection of cervical cancer, and they lead to a decline in the mortality rate of cervical cancer by about more than 50%. In a Pap test, the cells from in and around the woman's cervix are removed using a brush and sent for pathological examination to detect the presence of any abnormal cells (cancerous or precancerous).

  • Human Papillomavirus (HPV) Testing: HPV tests help detect strains of human papilloma virus in cells of a woman's cervix. Certain strains of HPV have a strong association with cervical cancer.

4. Prostate Cancer Screening:

  • Digital Rectal Examination (DRE): In DRE, the doctor checks for any irregularities on the surface of the prostate by inserting his gloved fingers into the rectum. DRE is not much preferred as a screening test by U.S Preventive Services Task Force because it is less effective and shows a lack of evidence in cervical cancer screening.

  • Prostate-specific Antigen Test ( PSA): In the PSA test, the levels of PSA in the blood are measured. Elevated levels of PSA are seen in prostate cancer, which helps detect prostate cancer early. High levels of PSA can even be seen in noncancerous conditions, so there may be some inaccuracy with the PSA test in prostate cancer detection.

4. Skin Cancer Screening: Skin cancer screening tests include a self-skin examination, skin examination by a dermatologist, and dermoscopy.

  • Dermoscopy: It is valuable in the early detection of conditions like melanoma. The procedure involves the examination of pigmented skin lesions using a device. It is also known as Epiluminoscopy or epiluminescence microscopy. Other screening tests like skin self-examination and skin examination by a doctor also help in early skin cancer detection. Consult your doctor if you find any abnormal skin changes through skin self-examination.

5. Colorectal Cancer Screening: Both of these procedures help in the early detection of colorectal cancer. In a colonoscopy, a colonoscope is used to look for any polyps or cancer in the colon. And in sigmoidoscopy, a sigmoidoscope is used to detect any cancer or polyp in the colon.

  • Stool DNA Test: In the stool DNA test,stool samples are collected and analyzed for any DNA changes in the cells of a stool sample. This helps detect colon cancer or polyps by looking for any abnormal DNA associated with it.

  • Double-contrast Barium Enema (DCBE): In DBCE, the individual who needs to be screened is asked to lie on an examination table, then a lubricated tube is inserted carefully into the rectum, and a bag containing barium is allowed to flow into the colon. When sufficient barium has filled the colon, then many X-rays are taken. This provides images of the colon that can detect colorectal cancer. Doctors recommend this screening technique in people for whom colonoscopy cannot be performed. Besides all the above-mentioned screening techniques, the fecal occult blood test is another screening test that helps in colorectal cancer detection. It detects the presence of blood in feces or stool. Blood-tinged stools and feces are warning signs of colorectal cancer.

What Are the Risks Associated With Cancer Screening Tests?

Even though cancer screening tests are highly valuable, they also have risks. The risks include

  • It may give out false-positive results in some cases.

  • It can have some harmful effects too. Screening tests like endoscopy can lead to bleeding in some cases. Radiation exposure as an output of cancer screening can induce cancer at times.

  • Sometimes cases may be misdiagnosed.


People often get misguided by contradictory information about cancer screening. Proper guidance from your healthcare provider gives you clarity. They are intrigued with questions like whether I need a screening test? If yes, then when and how to get it done?. The healthcare provider can only give answers to such questions properly. So consulting your healthcare provider before having a screening test is highly advisable.

Frequently Asked Questions


Can Blood Test Detect Cancer?

Most cancers cannot be detected in a routine blood test like a complete blood count or hemoglobin test. However, leukemia can be diagnosed with a blood test. Specific blood tests that are used to detect specific tumor markers can give indications of cancer. Imaging studies, laboratory tests (including tests for tumor markers), tumor biopsy, endoscopic examination, surgery, or genetic testing are used to detect cancer in the human body.


Can a Full Body Checkup Detect Cancer?

A full body checkup involves a series of tests and physical examinations to check the entire body. It can be used to find underlying conditions like cancer and other medical issues. These tests are done in authorized centers using specialized equipment. 


How Can One Detect Cancer Early?

A thorough physical examination helps to detect lumps and tumors and diagnose them early. Laboratory tests like blood and urine tests can help to understand abnormalities in the specimen, which can be suspicious of cancer. Imaging studies help to understand the exact location of cancer. Biopsies help to understand the type and other details of the cancer.


What Is the Best Full Body Scan for Cancer?

Positron emission tomography and computed tomography (PET-CT) help to check the full body for cancer. In this, PTE and CT scans are combined to evaluate the body. This helps to know the correct location to perform a biopsy. Hence the accurate type and stage of cancer can be understood. It can also be used to assess the treatment, and whether the body responds to the treatment, and helps in planning radiotherapy.


Can Full Body MRI Detect Cancer?

Yes, a full-body MRI will help to detect cancer. In addition, it can be used to detect aneurysms, bone and joint issues, and problems related to the spine. Tumors in the spine, pinched nerves, herniated discs, fractures, and spinal cord compression can be detected by an MRI. The procedure has a specificity ranging from 93 to 95 percent.


Does Protein in Urine Indicate Cancer?

Severe cases of cancer cause proteinuria. A urine test called the Bence-Jones is used to detect a type of cancer called multiple myeloma. Cancers like renal carcinoma, lung cancer, breast cancer, etc can cause proteinuria. Unexplained weight loss, fatigue, fever, pain, etc can be seen along with proteinuria.


Can an X-ray Show Cancer?

An X-ray can show changes in the parts of the body, that can be indicative of cancer. Pneumonia, lung cancer, tuberculosis, etc can be seen in a chest X-ray. Mammography is a special type of X-ray that helps to detect breast cancer. 


How Accurate Is CT Scan for Cancer?

A CT scan helps to give an idea of the tumor’s size, shape, and location. They even reveal the blood vessels that supply the tumor. Hence they are considered accurate. However, a CT alone cannot be used to confirm the diagnosis of cancer, as it can give false positive and false negative results.


What Cancer Is Related to Urine?

Bladder cancer occurs when the cells in the bladder begin to proliferate uncontrollably. Some other cancers detected in urine can include cancers in the kidney, prostate, and cervix. Cancer can reach the urine in two ways-through the kidneys or through the urinary system.


How to Detect Kidney Cancer?

Imaging studies are useful in detecting tumors or enlargement of the kidneys. Imaging studies can include ultrasound, X-ray, CT, or MRI scans. A biopsy helps to get detect the type and stage of cancer. Blood in urine, pain in the abdomen that does not go away, fatigue, unexplained weight loss, etc., can be indicative of kidney cancer.


How Much RBC in Urine Is Normal?

A very small amount of RBCs are normally found in urine. 4 blood cells per high-power field are the normal amount of RBCs in a sample of urine. If blood in urine persists for a long time, medical attention can be sought. Medical sought must be taken if associated with weight loss and discomfort during urination.


What Color Urine Is Abnormal?

The normal color of urine in a healthy person will be straw color. Cloudy, dark, or blood-colored, blue or green can be considered abnormal. Any deviation from the normal straw-colored can be considered abnormal. Cloudy urine can be a sign of a urinary tract infection. 
Dr. Rajesh Gulati
Dr. Rajesh Gulati

Family Physician


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