Metastatic lung cancer is a form of cancer that has spread to the lungs from other parts of the body. In metastatic lung cancer, cancer in other parts like the breast, colon, prostate, or bladder spreads to the lungs through the bloodstream and forms cancerous growth in the lungs.
This type of cancer in the lungs is called metastatic lung cancer. Thus, cancer that has spread to the lungs is said to have metastasized to the lungs. The symptoms of such lung cancer are cough, bloody sputum, shortness of breath, rib cage pain, weight loss and weakness.
Chest X-Ray, Chest CT Scan, cytology studies of pleural fluid or sputum, lung needle biopsy, surgical lung biopsy, and bronchoscopy are the methods available for the diagnosis of metastatic lung cancer.
Among them, the chest X-ray is the most commonly performed method to detect cancer. The procedure involves taking X-rays from the back to the front and also on the sides. For the detection of metastatic cancer, a CT scan is often used.
Diagnosis
To determine the extent of metastatic cancer in the brain, a CT scan is the preferred tool. This reveals the presence of metastatic cancer in the brain.
Other areas like the liver and adrenal glands can also be scanned with the CT scan. In certain circumstances, the lung cancer would have metastasized to the bones. In such cases, a bone scan is done to determine that.
The procedure for a bone scan involves the injection of radioactive material into the bloodstream. This radioactive material collects in the bones in the areas where metastatic tumours are present. The scanner detects these radioactive materials, and the image is recorded.
A blood test may also reveal the presence of metastatic cancer in the bones if an increased level of calcium or alkaline phosphatase is found. Similarly, an increased level of aspartate aminotransferase and alanine aminotransferase indicates the presence of metastatic cancer in the liver.
Treatment
Treatment for metastatic lung cancer is usually through chemotherapy. Metastatic lung cancer indicates that cancer has spread to the bloodstream, and due to this, cancer may be found in many places that are not detected by a CT scan.
Hence, chemotherapy is used for the treatment of such cancers. Sometimes metastases in the lungs can be removed by surgery as well. The brain is an important part that is affected by metastatic cancer.
Radiation therapy is given to the brain even if there is no cancer in the brain. This is to prevent any metastatic cancer in the brain. This kind of treatment to the brain is termed prophylactic cranial irradiation.
Consult your radiation oncologist regarding radiation therapy to your brain. Exposure of the brain to radiation may have side effects. The decision to have radiation therapy to the brain should be taken after the patient and the doctor discuss the possible risks and complications.
It is always better to prevent than to cure. Hence it is better to stop smoking and eat a healthy diet with regular exercise. Try to avoid alcohol or keep it at a minimum.
Genetic Mutations
Lung cancer patients who have never smoked are more likely than smokers to have one of two genetic mutations linked to the disease, according to researchers at UT Southwestern Medical Center. The results could help explain why some people with lung cancer respond very well to a certain type of targeted therapy while others don’t respond much or at all.
Mutations in the epidermal growth factor receptor (EGFR) gene are found primarily in adenocarcinomas, the most common type of lung cancer found in both smokers and nonsmokers, as well as in women and people under the age of 45. These mutations have increased sensitivity to the gene-targeting drugs gefitinib (Iressa) and erlotinib (Tarceva).
“This study describes the first known mutation to occur in lung cancer patients who have never smoked,”
said senior author Dr. Adi Gazdar, professor of pathology in the Nancy B. and Jake L. Hamon Center for Therapeutic Oncology Research.
KRAS vs. EGFR
Dr. Gazdar and his colleagues examined tissue samples from primary tumours of 519 patients from the United States, Japan, Taiwan, and Australia to understand better the role of the EGFR mutation in the development of lung cancer. Mutations in the DNA of nonmalignant lung tissue from many of these patients, as well as other cancer tissues, were investigated.
Mutations in the EGFR gene were found to be much more common in people with lung cancer who had never smoked compared to smokers (51 percent vs. 10%, 85 of 166 nonsmokers vs. 35 of 353 smokers); and in women compared to men (42 percent vs. 14 percent, 72 of 171 women vs. 48 of 348 men).
Eight percent of lung cancers had mutations in the KRAS gene, a gene involved in the EGFR signalling pathway, but none had the EGFR mutation. Males, Caucasians, and current or former smokers had a higher prevalence of this mutation.
GRN163L
A substance discovered by scientists at the University of Texas Southwestern Medical Center has the potential to stop the metastasis, or spread, of lung cancer. The compound inhibits an enzyme that is known to maintain cell immortality and is thought to be involved in almost all human cancers.
Based on findings in mice, they concluded that the substance, known as GRN163L, also operates quickly and in doses appropriate for therapy. To stop the spread of cancerous cells that remain after surgery, chemotherapy, or radiotherapy, it might be especially helpful.
GRN163L, which consists of 13 nucleotides — the building blocks of DNA — plus a fatty section that accelerates uptake by cells, was created, synthesized, and tested by the researchers. The telomere, a section of DNA at the end of each chromosome, is precisely matched by GRN163L. Telomeres typically get shorter and shorter as cells divide and get older. The cells stop dividing once they reach a specific length.
Cancerous Cells’ Telomeres
However, cancerous cells’ telomeres maintain their original length because of an enzyme called telomerase. Only a small percentage of non-cancerous cells and between 85% and 90% of tumors express the telomerase gene.
Although telomerase does not cause cancer, it does enable cancer cells to continue dividing. According to Dr. Shay, it is almost a universal target for cancer treatment, and its specificity is what attracts attackers.
Telomerase functions by attaching to DNA and preventing chromosome shortening with the help of a protein section. It appears that GRN163L prevents telomerase from binding.
Future animal experiments will combine GRN163L with other drugs, radiation therapy, and therapy to see how these other cancer treatments interact with it.
Last Updated on December 6, 2022