Small cell lung cancer is very aggressive
Lung cancer is one of the most common types of cancer. Each year, around 46,000 people in the UK are diagnosed with lung cancer. Lung cancer can be divided into two groups, depending on its appearance under a microscope; small cell lung cancer and non-small cell lung cancer. This article is about the small cell lung cancer type, which accounts for roughly 20 % - that is 9,200 – of all lung cancer cases. The cause is almost always smoking. Small cell lung cancer is very aggressive, and without treatment, the outlook for the condition isn't as good as it is for many other types of cancer. The prognosis depends on how early the diagnosis is made, and the prognosis will usually be worse if the tumour has spread. (1) In around 40 % of all cases, small cell lung cancer is discovered before spreading to other parts of the body, and here, the average survival is 16-24 months. In contrast, the average survival in cases where the cancer is discovered once it has spread to the opposite side of the chest or outside the chest is 6-12 months.
The most common treatment for small cell lung cancer is chemotherapy. Chemotherapy is a treatment method killing cells which divide frequently. The treatment is injected into the body which means that it is sent through the entire body, thereby killing cancer cells all over the body. Small cell lung cancer consists of cancer cells which grow quickly, and which often spread to other parts of the body, and therefore, chemotherapy is an effective treatment method. In fact, small cell lung cancer is the most aggressive type of lung cancer, and it often spreads in the early stages of the disease. This means that surgery is rarely an option once the disease is diagnosed. Patients often experience side effects during chemotherapy, because it also kills healthy cells. Other cells which divide quickly as well include bone marrow cells, and for this reason, patients undergoing chemotherapy must be checked for anaemia regularly. Small cell lung cancer often responds well to chemotherapy at first, but after a while when the tumour has shrunken and the symptoms are reduced, the cancer will often return. In fact, only around 10 % remain disease free for two years after the treatment. (2)
A research subject offers hope for other lung cancer patients
An American study has examined the effect of the drug nivolumab. This drug blocks the effect of a molecule called PD-1, which is a protein that affects cells in the immune system called T cells. PD-1 affects T cells so they do not recognize the cancer cells, as the T cell will not notice that the cancer cells are different from healthy cells. Because of this, T cells will not kill the cancer cells.
One of the patients from this study is 63-year-old Nina Beaty. At the beginning, she received traditional chemotherapy and radiation therapy. Her tumour responded well to the treatment, but within a year, it turned out that her tumour was starting to grow, and that it had spread to other parts of the body.
Nina Beaty’s doctor suggested that she enrol in the study testing nivolumab. Within just four weeks of being treated with nivolumab, the lung tumour had shrunk by almost half. This is a major step forward within the treatment of small cell lung cancer. She has thus benefited tremendously from participating in the study. Two years later, she continues to benefit from the treatment, despite the fact that she prepared to survive for only 6-12 months.
The effect is limited to a small group of patients
However, not all patients with small cell lung cancer respond as well to the treatment as Nina Beaty. In the study, only 10 % of patients, who experienced recurring small cell lung cancer after traditional chemotherapy, responded well to the treatment. If nivolumab was taken in combination with a drug called ipilimumab the response rate rose to 21 %. Still, a relatively small percentage benefit from the treatment, but for those who do respond well, it could mean the world.
Other medications
Other drugs for treating small cell lung cancer exist as well. These include the so-called “PARP inhibitors”. These drugs disturb important processes in the cancer cells, so they end up dying. Early clinical studies of PARP inhibitors have shown that the drug’s effect is comparable to that of traditional chemotherapy. When the two treatments were combined, the effect was even bigger – in some cases even tripled. (2)
The development of new drugs and treatment methods for the very aggressive kind of small cell lung cancer, which causes many deaths every year, draws a lot of attention at the moment. Hopefully, researchers will soon be able to find a drug or a combination of treatments which prolong patients’ lives or perhaps even heal patients altogether.
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