Unfortunately, patients with lung cancer often develop brain metastases. Once discovered, brain metastases are most often treated with radiation therapy, sometimes preceded by surgery.
For non-small cell lung cancer (NSCLC) patients with a solitary brain metastasis, that is, only one identifiable “spot” in the brain, surgery is often used in combination with radiation therapy. For NSCLC patients with multiple brain metastases, surgery offers less benefit. However, if the diagnosis is not clear, or if one of multiple lesions in particular is causing symptoms, surgery can helpful for both diagnosis and relief of symptoms. Relieving symptoms with surgery depends on the location of the lesion in regard to accessibility and function. If the lesion is in a non-critical brain area, it often may be surgically removed; however, if it is in a critical area (for example, the brain area that controls motor function of the right leg), surgery can lead to even worse function (of the right leg).
After surgery for NSCLC brain metastasis, radiation therapy is used to decrease the risk of brain metastases reoccurring or causing symptoms. Multiple options for radiotherapy treatment exist – mainly, whole brain irradiation and stereotactic radiosurgery. They can be used alone or together. For decades, standard treatment for lung cancer brain metastases has been whole brain irradiation. In more recent years, stereotactic radiosurgery has increased in availability and has been used increasingly.
Choosing the right treatment depends dramatically on patient circumstances. Let me describe a few situations:
Case #1: Mr. W is a 70 year old gentleman diagnosed with locally advanced squamous cell carcinoma of the lung, stage IIIB. He undergoes treatment with chemotherapy and radiation and the cancer generally responds well. Two months later, he develops a headache and brain imaging demonstrates three lesions in the brain, consistent with brain metastasis, with some associated swelling.
For Mr. W, proceeding to whole brain irradiation would be my general recommendation. Given the multiple brain metastases and short interval in which they developed, he is at high risk for development of additional brain metastases.
Case #2: Ms. X is a 36 year old woman with early stage adenocarcinoma of the right lung (T1N0). She underwent a surgery for removal of the right upper lobe of the lung containing the cancer and has no evidence of disease for 2 years. Then, she develops some very subtle weakness in the right leg. Her physician obtains a brain MRI which identifies a 2 cm mass in the region of the brain controlling the right leg, with some swelling. Restaging scans of the chest, abdomen, and pelvis identify no other areas of disease recurrence. She continues to work full time.
For Ms. X, I would recommend focused, single session, stereotactic radiosurgery treatment. Surgical resection is likely not a good option given the location of the metastasis. Whole brain irradiation is an option in this case; however, given the early stage of lung cancer initially and long interval before development of the brain metastasis, I would favor stereotactic radiosurgery, as Ms. X likely has less than the traditional 50% risk of developing additional brain metastasis. As well, in the short term, she will be able to obviate 2 to 3 weeks of daily whole brain treatment, and avoid the possible short term side effects of fatigue, nausea, vomiting, hair loss, and sore throat. She also will be able to keep working, with minimal interruption. In the long term, while whole brain radiation is generally safe, she may avoid the potential long term side effects of whole brain irradiation, such has some decrease in short term memory or ability to multi-task, which may also interfere with her job. If she opts for focused stereotactic treatment, she will particularly need close neurological follow-up and scheduled repeat surveillance brain MRIs.
Case #3: Mr. Y is a 49 year old gentleman diagnosed with stage IV lung cancer, with a large mass in the chest, liver, bone, and brain metastases. He has lost 60 pounds and getting out of bed is difficult.
For Mr. Y, I would recommend no aggressive directed therapy of brain metastases. I would encourage comfort and quality of life related care, with consideration of steroid medications to ease any symptoms related to brain metastases.
Case #4: Ms. Z is a 64 year old woman treated two years ago for a T2N2M0, Stage IIIA non-small cell lung cancer. She underwent surgery, then chemotherapy, then radiation therapy. Three months later, she was restaged with a brain MRI which detected a solitary 1cm brain lesion in the cerebellum (the lower, back part of the brain). She has no other sites of active disease.
Patients like Ms. Z face multiple reasonable choices regarding brain metastasis treatment. First, surgery is not an unreasonable option, given the lesion is likely surgically accessible. Second, whole brain irradiation, alone or in combination with surgery, is also good treatment – Ms. Z is at high risk of developing additional brain metastases, and will likely benefit from whole brain irradiation. Finally, stereotactic radiosurgery is also an option – the important thing to realize however is stereotactic radiosurgery that may only be prolonging an inevitable need for whole brain irradiation, although may cause less in terms of side effects.
In general, whole brain irradiation is safe and effective in suppressing known brain metastases as well as subclinical (no symptoms) and subradiographic (not visible on scans) disease. Stereotactic radiosurgery offers some benefits as a high dose focused treatment which is often only a single day of treatment, with potentially little to no time required for recovery. Altogether, it is important for patients and physicians to discuss these various options for treatment, their effectiveness, their limitations, and their optimal selection given individual circumstances.