Small cell lung cancer
small cell lung cancer (SCLC) Small-cell lung cancer), also called small cell lung carcinoma, is a form of lung cancer, usually classified as terminal. Studies have shown that this type of lung cancer has usually already spread by the time it is detected (although such spread cannot be seen on x-rays or other imaging tests), so SCLC usually does not has a cure
Epidemiology
SCLC accounts for about 15% of all cases of lung cancer. The most important risk factor in the development of small cell lung cancer is cigarette smoke, either from the same smoker or from another person. secondhand smoke[citation needed]. The association with chronic exposure to asbestos or radon is also important.
Pathology
Small cell tumors behave like hilar masses that are difficult to delineate radiologically, which in their growth encompass both bronchial and vascular hilar structures, progressively compressing their lumen, even without clear infiltrative lesions being seen endoscopically. More rarely, they present as nodules or parenchymal masses far from the hilum.
Origin
Electron microscopic studies show dense granules of neurosecretion in some of the tumor cells. The granules are similar to those found in Kulchistsky neuroendocrine argentaffin cells of the bronchial epithelium, especially in the fetus and neonate. The existence of neurosecretion granules, the ability of some of these tumors to secrete polypeptide hormones, and the presence of neuroendocrine markers in the immunohistochemical study, such as neuron-specific enolase, parathormone-like substances, and other products with hormonal activity, suggest that this Tumor derives from cells of the basal layer of the bronchial lining with neuroendocrine programming and is possibly an apudoma. Anaplastic oat cell carcinoma is the histological type most frequently associated with ectopic hormone production and paraneoplastic syndromes.
Histopathology
As its name indicates, small cell carcinoma is made up of small cells, round or oval in shape, with a lymphocytic appearance, although twice the size of a lymphocyte, with scant cytoplasm, round nuclei, and dense granular chromatin (in salt and pepper). Other small cell carcinomas are made up of spindle or polygonal cells (small spindle or polygonal cell carcinoma). The cells grow in masses that show neither glandular nor squamous differentiation.
Diagnosis
Physical examination and an individual's medical and family history can set the stage for an accurate diagnosis. Certain radiology tests, such as a chest X-ray, a CT scan of the brain, chest, and abdomen, as well as other tests including bronchoscopy, biopsies, and Pap smears confirm the diagnosis and stage of the cancer.
Treatment
In the limited stage, the most commonly used treatment is a combination of two or more chemotherapy drugs. These would be cisplatin or carboplatin combined with etoposide, usually given for about six months. Studies are currently underway to determine if the addition of topotecan or paclitaxel will improve survival.
Chest radiation therapy is not done in patients who have severe lung disease (other than cancer) or some other types of serious medical problems. Sometimes, if the SCLC is very localized, the cancer is removed by surgery and then adjuvant combination chemotherapy (polychemotherapy) is given.
In the advanced or disseminated stage, chemotherapy can treat the disease and allow the patient to live longer and better. The chance that the cancer will shrink with chemotherapy is about 70 to 80%. Again, carboplatin or cisplatin along with etoposide are the drugs that are usually given. However, eventually the cancer becomes resistant to treatment. Radiation therapy is sometimes used to control symptoms of growth within the lung or spread to the bones and brain. Sometimes they are treated with preventive radiation therapy to the brain.
Forecast
The one-year survival rate for people with limited-stage SCLC treated with chemotherapy and radiation therapy (this is the most favorable group) is 60%. At two years the rate decreases to 30%, and at 5 years it decreases from 15 to 10%. Due to the lack of satisfactory results, doctors are studying other methods to treat these cancers. Clinical trials of new chemotherapy drugs or other new treatments such as immunotherapy or gene therapy are a worthwhile option that can benefit both the individual patient and future patients.
Many studies have been done to find out if radiation therapy treatment to the chest (usually to the center, where the cancer spreads to the lymph nodes) will improve outcomes compared to chemotherapy alone. These studies have shown that radiation therapy provides little benefit. However, there will be more toxicity with radiation therapy in conjunction with chemotherapy. You may experience increased shortness of breath (dyspnea) due to damage to the lung, and difficulty swallowing (dysphagia) because the esophagus is in the radiation field.
About 20-30% of people with advanced-stage SCLC live for 1 year. At two years, only 5% remain alive. And only 1-2% of people with advanced-stage SCLC survive five years after the cancer is detected. If the patient is too sick to endure chemotherapy, the best plan is to provide palliative care. This would include treatment of any pain, breathing problems, and other symptoms the patient may be experiencing. In cases of advanced stage lung cancer the main problem may be pain. Cancer growth around certain nerves can cause severe pain. However, this pain can be relieved with medication. Radiation therapy may also be helpful.
Metastasis
It is fast growing and highly invasive. It characteristically invades the mediastinum and most frequently produces the superior vena cava syndrome. In general, the most frequent cause of superior vena cava syndrome is the oat cell and in second place would be lymphomas. SCLC commonly spreads to the brain. If preventive measures are not taken, approximately 50% of people with SCLC will have brain metastases. For this reason, if there is a good response to initial treatment, radiation therapy to the brain may be given to prevent brain metastasis. This may also slightly increase the chance of longer survival. One problem that doctors have reported is that patients receiving radiation therapy to the brain may suffer side effects such as memory problems and clumsiness. It is not fully clear whether these symptoms are the direct result of radiation. Most doctors will recommend radiation therapy to the brain if the patient has had a complete response (apparently all the cancer is gone) after chemotherapy. Such prophylactic (preventive) radiation to the brain has resulted in overall survival advantages, according to a recent review of several collated studies.