Making Decisions about Radiation Therapy for Limited Stage SCLC

Imprima English

Mitchell Machtay, MD
The Abramson Cancer Center of the University of Pennsylvania
Ultima Vez Modificado: 28 de abril del 2002

I have been diagnosed with limited stage SCLC and have started chemotherapy. The doctors tell me that radiation will be combined with the chemotherapy during the 4th round. They tell me that after radiation a lot of scar tissue will result and that I may be on oxygen for the rest of my life. I am seriously considering not having the radiation but continuing the chemotherapy. I am concerned with quality of life. How would this decision to not have radiation affect the outcome of my treatment and prognosis? The doctors have also told me that there is no cure.

Mitchell Machtay, MD, Assistant Professor of Radiation Oncology at the Hospital of the University of Pennsylvania, and Deputy Chairman of Radiation Therapy Oncology Group, responds:

According to a well-known radiation oncologist, untreated small cell lung cancer grows so quickly that "If you listen closely, you can actually hear it growing."

Small cell lung cancer is a very aggressive type of lung cancer, which is almost never treated with surgery. Unlike the more common non-small cell lung cancer, it is relatively sensitive to chemotherapy. This means that chemotherapy often shrinks the cancer; unfortunately, however, it usually grows back soon after chemotherapy and often eventually becomes "resistant" to chemotherapy. The term "limited" small cell lung cancer refers to cancer that has not spread beyond one side of the chest. If it has spread elsewhere, such as the liver or brain, it is considered "extensive stage."

While extensive stage small cell lung cancer is not considered curable, some patients with limited stage disease enjoy many years of cancer-free survival and even cure. The chance for prolonged remission and survival is significantly increased by the addition of thoracic (chest) radiotherapy to chemotherapy, as shown in a 1992 meta-analysis of older studies compiled by Pignon and colleagues1. In a more recent and large study by Turrisi on behalf of the Eastern Cooperative Oncology Group, approximately one third of patients treated with both chemotherapy and radiation survived for three years2. This is among the "best" results ever reported for this disease; most studies show that only about one in ten patients treated with chemotherapy alone survives for three years. In all studies (including Turrisi's), some patients suffered recurrences or new cancers (such as non-small cell lung cancers) after the 3-year mark, so it is difficult to determine what the true "cure" rate is.

As with all cancer therapies, the benefits of chest radiation must be weighed against its risks. As noted by the questioner, one of the side effects and risks of radiation to the chest is inflammation (pneumonitis) and/or scarring (fibrosis) of the lung, which can be permanent. Almost all patients who get chest radiation eventually have some of these side effects, but usually the symptoms are mild or even not noticeable at all. In its most severe form, however, radiation scarring can lead to permanent need for oxygen around the clock, even if the cancer is completely gone. The risk of such serious complications depends on many factors, including the size of the radiation "field" (area treated with radiation, which usually depends on the size of the cancer), radiation dose, and the extent of the patient's underlying medical conditions such as emphysema. In a study of lung cancer patients treated at the University of Pennsylvania (Robnett and colleagues), we found that the risk of serious lung complications was about 8%3. Patients who were extremely healthy before radiation (ECOG performance status 0) had only a 2% risk of severe lung damage, compared with 16% for patients who were generally healthy but had some other medical problems (ECOG performance status 1).

Pulmonary (Lung) function testing (spirometry and DLCO tests) is highly recommended before starting chest radiation. These laboratory tests, which are frequently done in people with asthma or emphysema, are done as an outpatient and are painless. Together with an assessment by a radiation oncologist and pulmonologist (lung specialist), these tests can help predict how strong a patient's lungs are prior to radiation. In general, if a patient with limited stage small cell lung cancer scores above 50% of "normal" on these tests, I think that the benefits of chest radiation outweigh the risks. Some patients with lower scores may still be candidates for carefully planned radiation, especially if one of the reasons for the bad score is the cancer itself. Sometimes, a patient's lung function can actually improve after radiation if the tumor shrinks.

In summary, there is a proven benefit to chest radiation for limited stage small cell lung cancer. But there are also proven side effects and risks. While some of these side effects can be extremely frightening, they are usually not as severe as the effects of an uncontrolled cancer within the chest. The decision on whether or not to go ahead and take chest radiation is admittedly difficult, but can usually be comfortably reached after appropriate tests, consultation with experts, and some soul-searching.

Pignon J, Arriagada R, Ihde D, et al: A meta-analysis of thoracic radiotherapy for small cell lung cancer. N Engl J Med 327:1618-1624, 1992
Turrisi ATr, Kim K, Blum R, et al: Twice-daily compared with once-daily thoracic radiotherapy in limited small cell lung cancer treated concurrently with cisplatin and etoposide. N Engl J Med 340:265-271, 1999
Robnett TJ, Machtay M, Vines EF, et al: Factors predicting severe radiation pneumonitis in patients receiving definitive chemoradiation for lung cancer. Int J Radiat Oncol Biol Phys 48:89-94, 2000