What Are The Most Common Cancer Types?
Cancer is not a single weed in the garden — it is more like an entire overgrowth of more than 100 different plant species. Each one grows in its own way, reacts differently to its environment, and responds differently to treatment.
Some grow quietly and slowly among the flowers.
Others spread quickly and take over large areas of the garden.
In this post, we will walk through the most common “plants” in this cancer garden. You will learn where they tend to grow in the body, how they behave, and how doctors name and classify them.
Because once you start to recognise these patterns, medical conversations become much easier to understand.
The Most Common
Cancer Types Worldwide
According to the World Health Organization, the most frequently diagnosed cancers globally include:
- Lung cancer
- Breast cancer
- Colorectal cancer
- Prostate cancer
- Skin cancer (non-melanoma)
- Stomach cancer
Other common types include:
- Melanoma (a more serious form of skin cancer)
- Blood cancers (such as leukemia, lymphoma, and myeloma)
- Brain cancers
Each of these cancers is different.
They grow differently, cause different symptoms, and require different treatments.
During this blog, we will deep dive into each of these cancer types at a later stage.
But, for now I would like to give you a brief introduction.
Common Cancer Types – Brief Description
Breast cancer
Breast cancer begins in the cells of the breast. While it mainly affects women, it can also occur in men.
There are different types, depending on where the cancer starts:
- Ductal carcinoma – starts in the milk ducts (most common)
- Lobular carcinoma – starts in the milk-producing glands
- Triple-negative breast cancer – a more aggressive form without common receptors
Common symptoms may include:
- A lump in the breast or underarm
- Changes in breast shape or size
- Skin changes or redness
- Nipple changes or discharge
You may want to listen to the MedTalk with Andrea – a breast cancer survivor.
Here, we discuss different breast cancer types in more detail, and you can learn about her treatment journey.
Lung Cancer
Lung cancer develops in the lungs and is often linked to smoking, although non-smokers can also be affected.
The two main groups are:
- Non-small cell lung cancer (NSCLC) – the most common, usually slower growing
- Small cell lung cancer (SCLC) – faster growing and more aggressive
Common symptoms:
- Persistent cough
- Shortness of breath
- Chest pain
- Coughing up blood
Colorectal Cancer
This cancer starts in the colon or rectum and is often linked to diet, inflammation, and family history.
Common types are:
- Adenocarcinoma – this is the most common type of colorectal cancer. It starts in the cells that make mucus and other fluids in the colon and rectum.
- Carcinoid tumors – these start in hormone-producing cells and usually grow slowly.
- Squamous cell carcinoma – a rare type that starts in the flat cells lining some parts of the rectum.
Common symptoms:
- Changes in bowel habits
- Blood in stool
- Abdominal pain
- Fatigue
Listen to this MedTalk with Dave Chuter and his friends about digestive cancer. He is a survivor and shares some valuable information with us.
Common Cancer Types – Brief Description
Prostate Cancer
Prostate cancer develops in the prostate gland and usually grows slowly.
The most common types are:
- Adenocarcinoma – this is the most common type of prostate cancer. It starts in the cells that make prostate fluid, which is part of semen.
- Small cell carcinoma – a rare, aggressive type that grows quickly and can spread early.
Common symptoms:
- Difficulty urinating
- Frequent urination (especially at night)
- Blood in urine
Skin Cancer
Skin cancer develops from abnormal skin cells, often due to sun exposure.
Main types include:
- Basal cell carcinoma – slow growing
- Squamous cell carcinoma – faster growing
- Melanoma – more serious and more likely to spread
Common signs:
- Changes in moles
- New skin growths
- Non-healing sores
Blood Cancers – The “Hidden” Cancers
Not all cancers form a visible tumour.
Blood cancers are different.
They are like changes in the water that nourishes the garden rather than a plant growing in one place.
They affect the blood, bone marrow, or lymphatic system.
The three main types are:
- Leukemia – affects blood-forming cells in the bone marrow
- Lymphoma – affects the lymphatic system
- Myeloma – affects plasma cells in the bone marrow
These cancers do not usually form a lump but can affect the whole body.
Blood cancers are a large and complex group with many different types and subtypes. Because they deserve a closer and more careful look, I will dedicate a separate blog post to them very soon.
Why This Can Feel Confusing
The word “cancer” is used for many very different diseases.
Some cancers:
- grow slowly
- stay in one place
Others:
- spread quickly
- affect the whole body
That’s why two people with “cancer” can have completely different experiences.
If this feels overwhelming — that’s completely normal.
Why Understanding Types of Cancer Matters
When you understand the different types of cancer:
- medical terms become clearer
- conversations with doctors feel less overwhelming
- you can ask better questions
- you feel more in control
Understanding is the first step toward feeling less lost.
Want to dig deeper?
If you’d like to understand terms like tumour, benign, or metastasis more clearly, you’ll soon find more dedicated articles here on the blog — each one breaking down a single concept in a simple, visual way.
If you want the whole structured journey, where everything connects step by step, you can also explore my book How to Speak Cancer.
It brings these topics together step by step and supports you in navigating the language of cancer at your own pace. Along the way, you will also find additional support, including links to patient organisations, glossaries of cancer and clinical trial terms, and a notes section where you can write down your own thoughts, questions, and key points to help you prepare for your next appointment with your healthcare team.