Important facts about the most common cancers

Skin cancer, lung cancer, prostate, breast cancer, and colorectal cancer are the top five most common cancers in the United States. For this reason, you should know some of the most important facts about the tests to diagnose them, what the most common types are, and which are most easily detectable and which are not, as well as which are the most treatable. This may help those of you who have not been screened or monitoring their health understand how important it is to use any means of preventive measures to reduce your risk. Always remember that with any type of cancer, early detection can be a life-saver. 

Tests used to diagnose these cancers

Only a biopsy can confirm the diagnosis of cancer. However, there are often other tests used before, in conjunction with, or after the biopsy to get a bigger picture of the diagnosis. 

• Skin cancer: Skin biopsy

• Breast cancer: Mammogram, breast ultrasound, MRI, breast biopsy

• Prostate cancer: PSA test, digital rectal exam, prostate biopsy

• Lung cancer: X-ray, CT scan, sputum cytology, lung biopsy

• Colorectal cancer: Colonoscopy, biopsy, CT scan, MRI, ultrasound, PET scan, complete blood count blood test, carcinoembryonic antigen blood test

Most common types and stages these cancers are diagnosed

All cancers are diagnosed at different stages. It depends on when a person gets screened. Certain risk factors increase a person’s risk for more advanced disease. For example, African-Americans (men and women) are more likely to be diagnosed with these types of cancer when they are advanced.

Skin cancer: Basal cell carcinoma is the most common cancer among Caucasians, Hispanics, Chinese Asians and Japanese people. Among African Americans and Asian Indians, squamous cell carcinoma is the most common type of skin cancer. 

• Stage 0: Cancer cells are confined to top layer of skin and have not spread. 

• Stage 1: Cancer cells have grown to a deeper layer of the skin, but have not spread to the lymph nodes or distant parts of the body. 

• Stage 2: Cancer cells have grown deeper, or have more high-risk features, but have not spread to lymph nodes or distant parts of the body. 

• Stage 3: Cancer cells have spread to nearby lymph nodes, but has not spread to distant parts of the body. 

• Stage 4: Cancer has spread beyond the skin and lymph nodes to distant organs within the body (i.e. liver, lungs, brain) or distant lymph nodes or other areas of the skin. 

Breast cancer: Invasive ductal carcinoma is the most common type of breast cancer. About 80% of all breast cancers are invasive ductal carcinomas.

• Stage 0: Non-invasive (in-situ) breast cancer.

• Stage I: Early stage invasive breast cancer; has not spread outside breast

• Stage 2: Still in early stages, but cancer has begun to grow and spread. Still confined to breast. 

• Stage 3: Advanced; cancer is invading surrounding tissues near breast. 

• Stage 4: Cancer has spread beyond the breast to other areas of the body.

Prostate cancer: Acinar adenocarcinoma is the most common type of prostate cancer. 90% of prostate cancers are acinar adenocarcinomas. 

• Stage 1: cancer is small and has not grown outside prostate.

• Stage 2: Cancer has not yet grown outside of the prostate, but are larger, have higher Gleason scores, and/or have higher PSA levels than stage I tumors.

• Stage 3: Cancer has grown outside of the prostate but has not reached the bladder or rectum. Has not spread to lymph nodes or distant organs. More likely to recur. 

• Stage 4: Cancer has spread to nearby areas such as the bladder or rectum, to nearby lymph nodes, or to distant organs such as the bones.

Lung cancer: Non-small cell lung cancer is the most common type of lung cancer. About 85% of lung cancers are non-small cell lung cancers. 

• Stage 1: Cancer is located only in the lungs and has not spread to any lymph nodes.

• Stage 2: Cancer is in the lung and nearby lymph nodes.

• Stage 3: Locally advanced; cancer is found in the lung and in the lymph nodes in the middle of the chest. 

• Stage 4: Advanced lung cancer; cancer has spread to both lungs, to fluid in the area around the lungs, or to another part of the body, such as the liver or other organs.

Colorectal cancer: Adenocarcinoma is the most common type of colorectal cancer.

• Stage 1: Cancer has spread beyond the inner lining of the colon to the second and third layers and involves the inside wall of the colon. Has not spread to the outer wall of the colon or outside the colon.

• Stage 2: Cancer is larger and extends through the muscular wall of the colon, but there is no cancer in the lymph nodes.

• Stage 3: Cancer has spread outside the colon to one or more lymph nodes.

• Stage 4: Cancer has spread outside the colon to other parts of the body, such as the liver or the lungs.

Not all cancers are as easily detected as others. However, for most cancers, early detection and early treatment can make a significant difference. It many cases, early treatment is a matter of life or death. Breast cancer, prostate cancer, skin cancer, and colorectal cancer are more easily detectable compared to lung cancer. This is because these types of cancers have routine screening tools to catch them in their early stages which are used as a preventive method. 

For breast cancer, there is a mammogram. For prostate cancer, there is a PSA test and digital rectal exam. For skin cancer, active monitoring of your skin to check for any abnormal changes in moles or spots. And for colorectal cancer, there is a colonoscopy. However, for lung cancer, there is no screening tool for early stage lung cancer except a low-dose computed tomography for smokers and former smokers at high risk. Most lung cancers are first diagnosed based on symptoms.

With early detection and treatment, these types of cancer are often highly treatable. In regards to lung cancer, it is a bit more challenging because lung cancer is difficult to catch in its early stage. However, if it is caught early, it is possible to treat and cure as long as the cancer has not spread to any lymph nodes. 

Many cancers often don’t show significant symptoms until the cancer is advanced. Once symptoms appear, the cancer may have already spread elsewhere in the body. This is why it’s important to get regular checkups and the recommended preventive routine screenings.