Cancer is a group of diseases that involve abnormal
growth of cells that can invade or spread to other parts of
the body. There are more than 200 types of cancer that
can affect different organs and tissues in the human body.
Cancer can cause various symptoms depending on its
location, stage and severity. Some common symptoms

– A lump or swelling in a part of the body
– Unexplained weight loss or gain
– Changes in skin color or texture
– Persistent cough or hoarseness

– Difficulty swallowing or breathing
– Changes in bowel or bladder habits
– Unusual bleeding or discharge
– Pain or discomfort in a specific area

However, these symptoms can also be caused by other
conditions that are not cancerous. Therefore, it is
important to consult a doctor if you notice any unusual or
persistent changes in your body.

## How is cancer classified?

Cancers are usually named according to the organ or
tissue where they start, such as breast cancer or lung
cancer. However, some cancers can start in more than one
type of cell or tissue, so they are further classified by the
type of cell they originate from. These types include:

– **Carcinoma**: Cancers that start in epithelial cells, which
are the cells that line the surfaces and cavities of the
body. This is the most common type of cancer and
includes cancers of the breast, prostate, lung, colon, skin
and many others.

– **Sarcoma**: Cancers that start in connective tissues,
such as bone, cartilage, fat, muscle and blood vessels.
These cancers are less common and include
osteosarcoma, chondrosarcoma, liposarcoma and others.

– **Lymphoma and leukemia**: Cancers that start in cells
of the immune system and blood. Lymphoma affects
lymphocytes, which are a type of white blood cell that
fight infections. Leukemia affects other types of blood
cells that are made in the bone marrow. These cancers are
more common in children than adults and include acute
lymphoblastic leukemia (ALL), chronic lymphocytic
leukemia (CLL), Hodgkin lymphoma and non-Hodgkin

– **Germ cell tumor**: Cancers that start in cells that
produce eggs or sperm. These cancers can occur in the
ovaries or testicles (ovarian germ cell tumors or testicular

cancer), or in other parts of the body where germ cells are
present (extragonadal germ cell tumors).

– **Blastoma**: Cancers that start in immature cells or
embryonic tissues. These cancers are more common in
children than adults and include neuroblastoma,
retinoblastoma, nephroblastoma and others.

Some cancers do not fit into these categories and have
their own names based on their features or location. For
example, melanoma is a type of skin cancer that starts in
melanocytes, which are cells that produce pigment. Kaposi
sarcoma is a type of soft tissue sarcoma that affects
people with weakened immune systems due to HIV/AIDS
or other causes.

## How is cancer diagnosed?

There is no single test that can diagnose cancer. Your
doctor will use various methods to find out whether your
symptoms are due to cancer or some other cause. These
methods may include:

– **Physical exam**: Your doctor will examine your body
for any lumps, swellings, changes in color or texture, or
other signs of cancer.

– **Laboratory tests**: Your doctor will order blood tests,
urine tests or other tests to measure the levels of certain
substances in your body that may indicate cancer. For

example, a complete blood count (CBC) can show
abnormal numbers or types of white blood cells in people
with leukemia.

– **Imaging tests**: Your doctor will use machines that
create pictures of the inside of your body to look for
tumors or abnormal areas. These tests may include X-rays,
CT scans, MRI scans, PET scans, ultrasound scans and

– **Biopsy**: Your doctor will take a small sample of tissue
from a suspicious area and send it to a laboratory for
analysis. This is often the only way to confirm if you have
cancer and what type it is. There are different ways of
taking a biopsy, such as using a needle, a scalpel, an
endoscope or a surgery.

– **Endoscopic exam**: Your doctor will insert a thin,
flexible tube with a light and a camera (endoscope) into
an opening in your body, such as your mouth, nose, anus
or vagina, to look for abnormal areas or take a biopsy.
This may be done for cancers of the digestive tract,
respiratory tract, urinary tract or reproductive tract.

– **Genetic test**: Your doctor may order a test to look for
changes (mutations) in your genes that may increase your
risk of developing certain types of cancer. This may be
done if you have a family history of cancer or if you have
certain syndromes that are linked to cancer.

## What happens if tests show you have cancer?

If your tests show that you have cancer, your doctor will
tell you the stage of your cancer. The stage describes how
much the cancer has grown and spread in your body. The
stage is based on the size and location of the tumor, the
involvement of nearby lymph nodes and the presence of
distant metastases (cancer cells that have spread to other
organs). The stage is usually indicated by numbers from 0
to 4 on TNM system by AJCC or by letters such as A, B or
C in group staging and staging by FIGO system. A higher
number or letter means a more advanced cancer.

The stage of your cancer helps your doctor determine
your treatment options and your chances of survival. Your
doctor will also consider other factors, such as your age,
general health, personal preferences and goals. You may
be offered one or more types of treatment, such as
surgery, radiation therapy, chemotherapy, immunotherapy,
targeted therapy or hormone therapy. You may also be
eligible to participate in clinical trials that test new or
experimental treatments.

Your doctor will explain the benefits and risks of each
treatment option and help you make an informed decision.
You may also seek a second opinion from another doctor
before starting treatment. It is important to ask questions
and express your concerns to your doctor and other
members of your health care team. They are there to
support you and provide you with information and

## Conclusion

Cancer is a complex and diverse group of diseases that
can affect any part of the body. There are many types of
cancer that are classified by their origin and features. To
diagnose cancer, doctors use various methods that
include physical exams, lab tests, imaging tests, biopsies,
endoscopic exams and genetic tests. The diagnosis
determines the stage of the cancer and guides the
treatment plan. Treatment options may vary depending on
the type and stage of the cancer and other factors. The
goal of treatment is to cure the cancer or control its
growth and symptoms.

I hope this article has helped you understand more about
cancer types and diagnosis. If you have any questions or
feedback, please feel free to contact me at


(1) A to Z List of Cancer Types – NCI – National Cancer
Institute. https://www.cancer.gov/types

(2) List of cancer types – Wikipedia.

(3) Types of cancer | Cancer Research UK.

(4) Cancer – Types, Causes, Diagnosis and Treatment of
Cancer – BYJU’S. https://byjus.com/biology/cancer/

(5) How Is Cancer Diagnosed? | Stanford Health Care.

(6) Cancer – Diagnosis and treatment – Mayo Clinic.

(7) Tests and Procedures Used to Diagnose Cancer – NCI.