How Cancer Is Diagnosed

How Cancer Is Diagnosed

David Hinds, Histotechnologist

Histotechnologist David Hinds is on MSK’s pathology team that helps diagnose cancer.

An accurate diagnosis is very important to choosing the best care plan for you. It can confirm if you have cancer, or another disease with similar symptoms.

Doctors use the results of many tests to diagnose the type of cancer. They also find out the stage of the cancer, and whether it has spread to other parts of the body.

Memorial Sloan Kettering Cancer Center (MSK) diagnoses cancer using many new technologies that were developed or improved here. We’re always researching ways to diagnose cancer with greater accuracy so we can improve cancer treatment results.

MSK Rapid Diagnosis for fast cancer treatment

MSK Rapid Diagnosis is a cancer diagnosis service. It’s for people who don’t know yet if they have cancer. They have imaging scans that show signs of cancer, but they don’t have an initial diagnosis.

The first step is a biopsy, a procedure done to take samples of tissue or cells to check for cancer. If your biopsy or other tests results show signs of cancer, the Rapid Diagnosis team will:

  • Give you an accurate diagnosis right away.
  • Quickly refer you to MSK medical, surgical, or radiation oncology experts for treatment.

Learn more about MSK Rapid Diagnosis of cancer.

We’re experts at diagnosing cancer

MSK treats cancer and diseases related to cancer. We diagnose thousands of cancers a year. Our experts have deep experience in diagnosing all types of cancer, including rare cancers.

Our radiologists and pathologists focus only on their area of cancer. For example, the pathologists on our Hematopathology Service team only diagnose diseases of the blood, blood-forming cells, and the lymphatic system.

MSK uses many types of tests and procedures to diagnose cancer. They include:

  • Imaging tests
  • Pathology and lab tests
  • Diagnostic procedures, such as endoscopy and biopsy
  • Genetic tests

Who diagnoses cancer at MSK

Radiologists perform imaging tests

Radiologists are doctors who use imaging tests to look for cancer. Examples are X-rays and MRIs.

Learn more about the role of imaging tests in finding and diagnosing cancer.

Pathologists use microscopes to look at cancer cells

Pathologists are doctors who use a microscope to make a diagnosis.

A pathologist also finds out the stage of the cancer. Staging is part of the diagnosis process. It tells us how advanced a cancer is. It describes the tumor’s size, location, and how far it has spread. Staging helps your care team choose the best treatment and follow-up care for you.

Learn more about the role of pathology in diagnosing cancer.

Diagnostic procedures

To diagnose cancer, we sometimes must use a procedure instead of a test. We may need to take a sample of your tissues or cells, or look inside your body.


Doctors often recommend a biopsy if a physical exam or diagnostic test suggests cancer. A biopsy is a procedure done to take samples of tissue or cells to check for cancer. During a biopsy, your doctor removes a small number of cells or tissue so a pathologist can examine it.

Learn more about MSK Rapid Diagnosis of cancer.


During an endoscopy, your healthcare provider uses a flexible tube called an endoscope to see the inside of your body. During this procedure, they can also take a small tissue sample or remove a polyp (growth of tissue).

Testing cancer tumors for genetic mutations

Genetic testing is important for diagnosing cancer and for treating cancer. Genetic information helps us target a tumor with drugs that work best on that kind of cancer.

It also lets us predict how well a tumor may respond to treatment options. If testing suggests a treatment approach may not work well, we can pivot to a different therapy.

We use a testing tool only offered at MSK called MSK-IMPACT®. It’s for people with advanced cancer, and also for some early-stage cancers.

This test looks at about 500 genes for genetic changes (mutations or variants) and other tumor traits.

MSK also uses tumor genomic testing for certain early-stage cancers. We can confirm the tumor subtype and learn if there’s a risk the cancer was inherited.

Some cancers are caused by the genes you were born with. If so, your family also may be at higher risk for the same or other kinds of cancers.

Screening for cancer

Cancer screening is checking for cancer in people who don’t have symptoms. Screenings can help find cancer early, when it’s easier to treat. Screening can save lives by lowering chances of dying from cancer.

There are several kinds of screening tests. Screening can be done with blood tests, which are a type of pathology test. Some screenings are done with imaging tests, such as computed tomography (CT) scans. Cancer screenings have benefits and risks. Experts agree that for most people, screenings have more benefits than risks. 

Learn more about MSK’s screening guidelines and services.

People who are uninsured or underinsured can be screened for cervical, breast, prostate, and colorectal cancers at MSK Ralph Lauren Center in Harlem.

Second opinions on cancer diagnosis & treatment

MSK’s remote second opinion service brings together our experts in pathology, imaging, and cancer. A second opinion can help you be sure you have the most accurate cancer diagnosis and the best care plan.

Even if you cannot travel to New York for an appointment, MSK experts can give you their medical opinion. They review your pathology reports, imaging tests, and other medical information. They will make sure you have an accurate diagnosis and treatment plan.

Getting a cancer second opinion at MSK

MSK experts offer second opinions wherever you are, no matter where you’re getting treatment.

Getting a second opinion can help you be sure you have the most accurate diagnosis and the best care plan.

Please call our care advisors at 800-525-2225. They are available from 8 a.m. to 6 p.m. (Eastern time), 7 days a week.

You can also request an appointment online. The form will ask for your personal information and some basic questions about your diagnosis. After you fill out the form, you can schedule a time to talk with a care advisor.

MSK’s Patient Access Service will match you with the best healthcare provider for your diagnosis. The first time you call, we will pair you with an expert who is familiar with your type of diagnosis.

Learn more about MSK second opinions for a breast cancer diagnosis.

Learn more about MSK second opinions for brain cancer or a benign (not cancer) tumor diagnosis.