Lung Metastasis Explained

Lung metastases are one of the most common secondary cancers and often the most fatal one too. These cancers, which have their origin in another part of the body, actually spread from their original site through lymphatic or blood circulation to places the blood flows. Once they set in lungs, they create real dangers to life.

LUNG METASTASIS is a CANCER tissue that has spread to lung from another part of the body, where it originally developed.

An Introduction to Metastasis: Spreading of Cancer in the Body

METASTASIS refers to spread of cancer from the place it originated to a new place within the body. It is one of the characteristic features of cancer and can be considered the major difference between a malignant and non-malignant tumor.

Metastasis means the cancer cells which are growing uncontrollably are not restricted to one place in the body, and because of their spread to different parts of the body, they are no more amenable to surgical removal. Once the cancer cells have undergone metastasis, one or more secondary tumors will start developing in different parts of body like lymph node, lung, liver and bone.

The cancer cells spread through lymph. The growing cancer cells invade a local lymph vessel and damage its wall, from where they enter lymph and reach lymph nodes. For some time, they are restricted there, and after some time, they enter the blood stream and spread all over the body. Since all blood passes through the lungs for oxygenation, lungs are one of the most common places where the metastasis is deposited leading to growth of a secondary tumor.

A metastasis can be found in the lungs almost 40% of times the cancer has spread.

Cancers which Commonly Lead to Lung Metastasis

Any cancer can lead to lung metastasis. However, cancers arising in intestines spread more commonly to the liver, as the blood from stomach and intestines first goes to liver, and so cancers of stomach and intestines are more likely to result in metastasis in liver. Most other organs have a greater chance of metastasis in lung. The most common cancers that cause lung metastasis are Breast Cancer, Colon Cancer, Prostate Cancer, Stomach Cancer, Ovarian Cancer, Kidney Cancer, Malignant Melanoma, Esophageal Cancer, Head and Neck Cancers and Testis Cancer.

Symptoms & Signs of Lung Metastasis

In most patients, the lung metastasis is detected while the patient is being investigated or treated for the primary cancer. Most such cases of secondary tumor have no symptoms of their own and are detected by the investigating physician. In some cases, however, it can be the other way round, when a primary cancer remains silent and the secondary tumor in lung resulting from metastasis leads to symptoms because of which primary tumor is detected.

The usual symptoms of lung metastasis include cough, bleeding in sputum, pain in chest and difficulty in breathing. Most of these symptoms will however be present only in advanced stage of secondary tumor.

Detection & Diagnosis of Lung Metastases

Whenever a cancer is detected, the patient is subjected to complete testing and profiling that include X-ray of chest, and sometimes CT scan of the chest. The secondary tumor is detected by these tests.

Treatment of Lung Metastases

In case of a solitary metastasis, surgery can be attempted. One of the most famous patients who survived a lung metastasis removed by surgery was Winston Churchill, who was operated for a solitary metastasis from cancer of kidney in 1939 and survived for long thereafter. In most cases, however, surgery may not be feasible because of multiple metastases, and hence the only viable option may be chemotherapy. External beam radiotherapy may be used as adjunct to chemotherapy is some cases.