Lung metastases: symptoms, healing, survival

When a tumor grows in a place other than where it started, this is called a metastasis. Most often, a cancer that becomes metastatic sends metastases to certain organs like lung, brain, bone or liver. 30% people with a solid tumor (all cancers are called a solid tumor except leukaemia, whose cancer cells circulate in the blood or the lymph) would develop lung metastases according to a 2019 study published in the Swiss Medical Review. What are the warning symptoms of lung metastases? Where are they located? How to diagnose them? With what treatments to treat them? What are the chances of recovery and life expectancy? Update with Dr. Paul Cottu, oncologist at the Institut Curie.

“A pulmonary metastasis is a tumor that has spread to the lung” defines in the preamble Dr. Paul Cottu, medical oncologist. The tumor can spread anywhere in the lung. It can colonize a single lung or both. The cancers that most often give pulmonary metastases are:

• THE colorectal cancer (a 2017 study shows that 5% of patients with colorectal cancer will develop lung metastases)
• THE bone cancer or osteosarcomas (about 85% of distant metastases from osteosarcoma are located in the lung)
• THE breast cancer
• THE kidney cancer (renal carcinoma)
• ENT cancers (head and neck, or VADS)
• testicular cancer
• Soft tissue sarcoma
• melanoma
• Thyroid cancer

>> Caution, breast cancer that gives metastases to the lung, for example, does not turn into lung cancer. We talk about “metastatic breast cancer”.

A tumor can metastasize anywhere in the lung or to regions outside but very close to the lung. Most often, it metastasizes:

• near the lung wall,
• in the lower lobes of the left or right lung (or both),
• in the upper lobes of the left or right lung (or both),
• in the pleura and mediastinum.

“Bones, liver, lung and brain are the organs most often prone to metastasis“, specifies the oncologist. In certain cases, a cancerous cell located at the level of the lung remains long silent and does not cause symptoms. In other cases, lung metastases are symptomatic and can lead to:

• episodes of fever,
• an intense and persistent cough,
• shortness of breath,
• coughing up blood,
• severe pain in the chest or chest”especially if the cancer cell has reached the pleura, the envelope of the lung which is very innervated“, specifies Dr Maurice Pérol, medical oncologist specializing in thoracic cancers at the Léon Bérard Center in Lyon,
• frequent bronchial or lung infections (bronchitis, pneumonia, etc.),
• sudden weight loss.

All cancers can metastasize, in other words, migrate away from their original location. The risk of cancer progressing to metastatic cancer depends on several parameters, including:

• the type of cancer,
• the size and location of the primary cancer,
• how quickly the primary cancer grows,
• the likelihood of it spreading,
• the time of presence of the primary tumor in the body.

>> To know : metastases can develop very quickly or several years after the initial diagnosis, while some cancers will never metastasize.

First of all, a clinical examination makes it possible to assess the symptoms and to look for the presence of metastases. Then, blood tests (complete blood count, oxygen saturation, dosage of tumor markers according to each patient) make it possible to check the overall state of health of the patient, to see if there is pulmonary insufficiency or if a primary cancer has spread to the lungs.

Imaging examinations: X-ray, CT, PET…

Imaging tests will guide the diagnosis:

• An x-ray of the lungs is the first test to be done to determine the cause of a persistent cough or shortness of breath. It can also detect the presence of cancerous cells in the lung.
• A computed tomography (CT) scan of the chest provides more accurate images than an x-ray of the lungs and is used to check for the presence of lung metastases, to accurately and reliably determine their size and location. It also allows you to see if there are metastases in nearby lymph nodes.
• A positron emission tomography of the lungs (PET) allows, thanks to the use of a radioactive material, to obtain 3D images that help to know how far the tumor has spread.

Biopsy and other examinations

A bronchoscopy allows you to examine the inside of the bronchi and lungs using an endoscope. Finally, a biopsy confirms the diagnosis and clarifies the nature of the cancerous lesion. It is based on the removal by puncture or by endoscopy of a sample of suspicious tissue. This sample is then examined under a microscope. If the pulmonary metastases are detected before the primary cancer has been diagnosed, the doctor may request the realization other exams to determine the original location of the primary cancer and check for metastases in other parts of the body: mammogram if breast cancer is suspected, CT scan of the abdomen if colorectal cancer is suspected , a thyroid ultrasound if thyroid cancer is suspected…

“THE treatment plan is defined by the medical team. It is adapted to each patient according to their age, their general state of health, their preferences in terms of treatments, the location of their primary tumour, the extent, the number and the size of the metastases, the symptoms, the treatments already received…” list the oncologist. This plan is based on the combination of several treatments including:

>> Chemotherapy: reference drug treatment for pulmonary metastases, it reduces the size of tumors and limits their spread.

>> Targeted treatment which involves giving drugs (which contain certain proteins) that slow the growth and spread of lung metastases. The choice of drug depends on the location of the primary cancer. Targeted therapy is often combined with chemotherapy.

>> Hormone therapy which blocks certain hormones in order to slow the growth of certain metastases. This treatment is particularly used if the metastases come from breast or thyroid cancer.

>> Immunotherapy strengthens the patient’s immunity: his immune system is better able to detect cancer cells and destroy them.

>> Surgery involves removing a small part of the lung (the tumor and a small part of the healthy tissue around the cancer cells). This technique, performed by a thoracic surgeon, is particularly indicated if the metastases are isolated (ie if they have colonized only part of the lung) as well as to treat lung metastases from colorectal cancer, bone cancer or soft tissue sarcoma. “Not everyone with lung metastases can have surgery. The indication will depend on the size of the metastases, their location, their number and other factors related to the patient (age, history, etc.)“, specifies the expert. The surgeon can also extract the metastases by radio frequency (an electric current produces heat capable of destroying the tumour) or by laser (a very high intensity light beam produces heat capable of destroying the tumour). Complete disappearance of metastases is very rare. Nevertheless, treatments manage to make them regress and control their spread.

>> Supportive treatments do not treat metastases but can relieve certain associated symptoms such as respiratory problems, coughing up blood or accumulation of fluid in the pleura. This may be oxygen therapy (in case of breathing difficulties), a thoracentesis (in case of pleural effusion), external radiotherapy Or stereotactic radiotherapy (in case of coughing or bleeding).

Lung metastases have a better prognosis than lung cancers. Globally, “the 5-year survival rate for all stages of lung cancer is around 17-18%“, says Dr Pérol. For lung metastases:

• The largest collection of data to date from the “International Registry of Lung Metastases” of the European Society for Thoracic Surgery, indicates that cancer that has spread to the lungs is linked to the survival of 36% at 5 years And between 11 and 34% at 10 years.
• I’study “Lung metastases” published in 2017 on “Swiss Medical Forum” shows that pulmonary metastases from a colorectal cancer are associated with survival of 45 to 60% at 5 years and that those from a renal cell carcinoma are associated with a survival of approximately 40% at 5 years.

Thanks to Dr. Paul Cottu, medical oncologist at the Institut Curie in Paris and Dr. Maurice Pérol, medical oncologist specializing in thoracic cancers at the Center Léon Bérard in Lyon.