Cancer tests and scans are essential for diagnosing, staging, and monitoring the progression of cancer. There are various types of tests and scans used depending on the type of cancer and the clinical situation. Here's a breakdown of the most commonly used ones:

1. Biopsy

* What it is: A biopsy is the removal of a small piece of tissue for examination under a microscope. It's the most definitive way to diagnose cancer.

Types:
* Needle biopsy: A needle is used to extract tissue or fluid.
* Surgical biopsy: Tissue is removed through a small incision.
* Endoscopic biopsy: Tissue is collected during an endoscopy.

2. Blood Tests

* Complete Blood Count (CBC): Measures levels of different blood cells. Some cancers, like leukemia, affect blood cell counts.
* Tumor Markers: Certain proteins, enzymes, or substances in the blood may indicate cancer.

Examples:
* PSA (Prostate-Specific Antigen) for prostate cancer.
* CA-125 for ovarian cancer.
* CEA (Carcinoembryonic Antigen) for colon and other cancers.

3. Imaging Scans

A - X-Ray
* What it is: A quick and simple imaging technique that uses radiation to create images of structures inside the body.
* Usage: Often used for bone cancer, lung cancer, or to detect fractures or abnormalities.

B - CT (Computed Tomography) Scan
* What it is: A detailed, cross-sectional imaging technique that uses X-rays from different angles.
* Usage: Commonly used to detect tumors, determine their size, location, and whether cancer has spread to lymph nodes or other organs.

C. MRI (Magnetic Resonance Imaging)
* What it is: Uses strong magnetic fields and radio waves to create detailed images of the inside of the body.
* Usage: Particularly good for imaging soft tissues, such as the brain, spinal cord, muscles, and organs like the liver.

D - Ultrasound
* What it is: High-frequency sound waves create images of the inside of the body.
* Usage: Often used for breast cancer, liver cancer, and reproductive organ tumors.

E. PET (Positron Emission Tomography) Scan
* What it is: A type of nuclear medicine imaging that uses a radioactive substance to detect active, growing cancer cells.
* Usage: Often used to find cancer spread or recurrence.

F. Bone Scan
* What it is: A nuclear medicine scan that detects bone abnormalities using a small amount of radioactive material.
* Usage: Often used to detect bone metastasis (cancer spread to the bones).

4. Endoscopy

* What it is: A procedure using a thin tube with a camera to view the inside of organs or take samples (biopsies).
Types:
Colonoscopy: Used for colon cancer screening.
Gastroscopy: For stomach and esophagus cancer.
Bronchoscopy: To examine the lungs and airways.

5. Genetic Testing

* What it is: Analyzing DNA to identify genetic mutations associated with certain types of cancer.
* Usage: Helps to determine if someone has a higher risk for cancers such as breast, ovarian, or colon cancer (e.g., BRCA1 and BRCA2 for breast cancer).

6. Molecular Testing

* What it is: Examining tumor tissue to look for specific mutations, proteins, or other markers that may guide treatment.
* Usage: Common in targeted therapy for cancers like lung, colorectal, and melanoma.

7. Pap Smear and HPV Testing

* What it is: A screening test for cervical cancer that detects abnormal cells in the cervix.
* HPV testing: Detects human papillomavirus, which is associated with a high risk of cervical cancer.

8. Mammography

* What it is: A specialized X-ray of the breast.
* Usage: Used to detect early signs of breast cancer.

9. Colon Screening Tests

* Colonoscopy: As mentioned, used for colorectal cancer screening.
* Fecal Occult Blood Test (FOBT): Tests for blood in the stool, which could indicate colorectal cancer.
* Stool DNA Test: Detects abnormal DNA associated with colorectal cancer in stool samples.

10. Liquid Biopsy

* What it is: A blood test that detects cancer cells or fragments of tumor DNA circulating in the bloodstream.
* Usage: Being increasingly used for monitoring cancer progression or recurrence without the need for invasive tissue biopsies.

These tests and scans are crucial not only for diagnosing cancer but also for staging it (determining how far it has spread), monitoring response to treatment, and detecting recurrence after treatment is complete. Your doctor will choose which tests are appropriate based on your symptoms, cancer type, and other factors.