Feb 08, 2023
How Cancer Spreads
Cancer describes an abnormal process where healthy cells lose their ability to control their growth. As a result, they start growing chaotically and uncontrollably.
It begins with one cell, which initially multiplies until it forms a small bump. We call this the primary location. Without proper treatment, the cancer cells will keep growing and taking over space from healthy tissues. If the tumour is still confined within the basal membrane of the primary site, we call it carcinoma in situ. Stages I, II, and III of cancer depict the spread of malignant cells to different tissues. However, all of these stages still describe a local or regional.
When cancer spreads beyond its primary site to infiltrate distant organs and tissues, we give it stage IV. Doctors call this stage metastasis.
The most common areas that develop secondary tumours include:
- Lung bones
- Lymph nodes
How cancer spreads
Cancer metastasizes in the body following one or more of these routes:
- Direct invasion of nearby tissues
- Travelling via blood vessels to reach distant parts of the body
- Infiltrating a lymph node to travel via the lymphatic circulation to other organs
Once it reaches a secondary location, it grows until it forms a new tumour. It will also stimulate the angiogenesis process, allowing new blood vessels to surround the tumour and supply it with oxygen and nutrients.
Fortunately, most metastatic cancer cells die before achieving a secondary location. However, some cases may favour the spread of cancer, leading to the invasion of different body parts.
While every cancer can metastasize, the following tumours are most likely to:
- And Bone cancer.
We should note that when cancer spreads from one part of the body to another does not mean it is contagious to other people.
There is a common myth that surgery and exposure to external elements (e.g., oxygen) may contribute to the spread. However, researchers couldn’t find concrete evidence to support this hypothesis, especially with today’s advanced equipment. With that said, surgery could spread cancer in extremely rare situations.
Common spreading sites of cancer
While cancer can spread anywhere in the body, specific locations are more prone to hosting. Additionally, particular tumours tend to prefer some areas to metastasize. For instance, breast cancer often travels through the lymphatic circulation to distant lymph nodes.
The following sections will cover the most common cancers that spread to these organs, as well as the general signs and symptoms to expect:
Metastasis in the bones
When cancer spreads to the bones, it will cause severe bone pain and weaken your bones’ structure. In addition, some patients discover metastasis after enduring a bone fracture.
Metastasis in the brain
Unfortunately, the brain is a common site for metastasis. It also has one of the poorest outcomes.
Patients with brain metastasis report the following symptoms:
- Severe headaches
- Possible seizures
- Behaviour changes
- Vision problems
- Difficulty walking
Metastasis in the lungs
Following the bloodstream, cancer cells often find themselves within the pulmonary tissues. This may trigger chest pain, a chronic cough, hoarseness, dyspnea (i.e., shortness of breath), and hemoptysis (i.e., coughing up blood).
Metastasis in the liver
Breast cancer often travels to the liver, leading to an array of symptoms, such as:
- Weight loss
- Nausea and vomiting
- Abdominal pain
- Pain near the scapula
- Jaundice (i.e., yellowish colour of the skin and mucosa)
- Itchiness all over the skin
- A feeling of fullness under the ribs
Metastatic cancer symptoms
The symptoms mainly depend on the affected organ(s). For example, cancer growing large enough may only cause local symptoms at the primary tumour site. Alternatively, you may experience other symptoms in remote areas, such as the brain, lungs, or liver.
Watch out for these symptoms as they may indicate that the cancer is back:
- Weight loss
- Lost appetite
- Persistent headache
- Lethargy (i.e., extreme fatigue)
- Persistent cough
- Blood in the stool
- Urinary symptoms
- Post-menopausal bleeding
- Swollen lymph nodes
- Digestive problems
- Breast lump
- Chronic pain
- Random skin bruising
- Difficulty swallowing
The treatment of cancer
The treatment of metastasis focuses on stopping the growth and spread. However, it will also consider the type, location, size, and origin.
In many cases, your doctor will focus on systemic treatments. This is because the cancer is not located in a confined area. Therefore, it would be futile to focus solely on one site. These therapies include chemotherapy, hormone therapy, targeted therapy, and immunotherapy. Your doctor may also suggest radiation therapy and surgery in some cases.
The eligibility to participate in ongoing clinical trials makes treatment somewhat unique. These treatments are under development, and many target advanced cases (e.g., metastasis).
If you fulfil all the criteria set by the clinical trial authors, you will get access to novel treatments. While these therapies do not guarantee your recovery, they are significantly better than standard-of-care options.
Aside from these therapeutic modalities, there is another category called palliative treatment.
What is the palliative treatment?
Palliative treatment aims to relieve the symptoms and side effects experienced by patients with cancer. In principle, this treatment focuses on improving patients’ quality of life.
Your doctor will recommend palliative treatments only when other therapies stop working. Then, you can receive palliative treatment at home or in a palliative care unit.
Metastatic cancer is the IV stage of malignant tumours. Treating these cancers is challenging. However, recent advances in hormonal therapy and targeted therapy have made it possible to increase the survival rates of patients.
We hope this article highlights the major aspects of cancer metastasis and how we can identify and treat it.
If you have any questions about metastatic cancer, we recommend you consult the oncologist for tailored medical advice.