Thursday, April 24, 2014

Adenocarcinoma of the Lung and Brain Metastases

Definition

Article updated and reviewed by Kevin Knopf, MD, MPH; Director of Clinical Research, Annapolis Oncology Center and Associate Staff, Johns Hopkins Oncology Center on July 7, 2005.

Adenocarcinoma is a type of cancer, and adenocarcinoma of the lung is one type of non-small cell lung cancer that often develops along the outer edges of the lung and under the membranes lining the bronchi. It is the most common type of non-small cell lung cancer.

Metastasis (or metastases, pleural) means that a cancer has left its primary site and spread to a different part of a body.

Brain metastasis refers to when a cancer has spread to the brain from another site in the body, most commonly the lung or breast. There can be one or more than one metastases to the brain, and the cancer can go to different parts of the brain.

Description

Adenocarcinoma of the lung is the most common type of lung cancer and accounts for 30 to 35 percent of primary lung tumors.

The most common source of intracranial (within the brain) metastasis is cancer of the lung. Other primary cancers that can go to the brain include breast, kidney, melanoma, and cancers of the gastrointestinal tract (e.g., stomach, colon, and rectum).

Symptoms

Metastatic brian tumors manifest in a similar way as do primary brain tumors. They can cause increased pressure in the brain which can create headaches, nausea, vomiting, and tiredness. Because each part of the brain affects different parts of the body, metastatic cancer to the brain can cause changes in the nervous system such as weakness of part of the body, difficulty walking or speaking, or changes in sight. Some metastases can increase the chance for a seizure. Brain metastases almost never cause pain.

Adenocarcinoma of the lung manifests as do most lung cancers. Patients can develop shortness of breath, persistent cough, voice changes, weakness, or occasionally some bleeding with cough. Patients with lung cancer can also manifest signs of weakness, loss of appetite, and weight loss. Unfortunately most lung cancers are recognized at a late (advanced) stage.

Diagnosis

The diagnosis relies upon the medical history, physical examination, and radiological studies such as a chest CT (computed tomography) scan for lung cancer. Imaging of the brain is with a head CT or a head MRI (magnetic resonance imaging). CT scans and MRIs are often administered with a contrast agent by vein (IV contrast) which allows for better definition of suspicious areas that could be cancer.

Treatment

The treatment of brain metastases depends on factors such as the tumor of origin (for example, adenocarcinoma of the lung), the number and location of the lesions within the brain, and the extent of cancer in places other than the brain. Most patients are placed on steroids (Decadron) to relieve significant brain swelling that can cause severe symptoms. Patients may also take an anti-seizure medicine, since seizures are a common complication, although there is no evidence that anti-seizure medicines benefit patients who have not had a seizure.

The blood supply of the brain has a “barrier” which does not allow for chemotherapy to reach brain tumors. For this reason, radiation therapy is a cornerstone of treatment of brain metastases.

The standard approach with brain metastases of any other origin is to decide whether the tumor can be removed. A head CT scan or a head MRI is helpful in determining if there is more than one tumor and to define the specific sites in the brain where the tumor or tumors are located. In patients with only a single brain tumor, or two or three different sites of metastases, who are otherwise healthy, it may be possible to surgically remove the tumor and then treat with irradiation.

A newer technique available in specialized medical centers is called stereotactic radiation. This uses radiation therapy which is precisely localized to the site of brain metastases. This is sometimes referred to as “stereotactic radiosurgery”.

In patients with multiple brain metastases or widespread disease outside of the brain, the prognosis is often gloomy and treatment is palliative (reducing the severity of symptoms).

Adenocarcinoma of the lung is treated according to the stage of the cancer. For early-stage lung cancers, surgery can often be performed with curative intent, often followed by chemotherapy which increases the chance of cure. For more advanced lung cancers, radiation and chemotherapy are sometimes used. Lung cancers that have metastasized are treated with chemotherapy and/or radiation therapy.

There are newer agents called tyrosine kinase inhibitors that are given as pills that have a role in lung cancer; there is a suggestion that adenocarcinomas may be more sensitive to these agents. A newer type of chemotherapy called targeted therapy is exemplified by Tarceva, a pill with less side effects than traditional chemotherapy used in refractory cases of lung cancer.

Questions

What is the staging of the primary cancer?

What are treatment options?

Is surgery indicated?

Would chemotherapy or radiation therapy help?

What are benefits and risks of the treatment options?

Should participating in clinical trials be considered?

What is the short-term prognosis?

What is the long-term prognosis?

What are the side effects of treatment?

Are any clinical trials available for me?

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Editorial review provided by VeriMed Healthcare Network.

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