Wasim (name changed on request), a 52-year-old man from Coimbatore, was diagnosed with small cell lung cancer in 2020. He had earlier experienced recurrent cough, one of the primary symptoms of the condition that is also known as small cell carcinoma or oat cell carcinoma.
“The tumor was found in the lymph nodes surrounding his lung,” says Dr T Sujit, consultant radiation oncologist, American Oncology Institute, Coimbatore, Tamil Nadu, his treating doctor.
Treated with chemotherapy and radiation, Wasim got better but the cancer relapsed in the lung and neck nodes in two years.
While his lung responded well to chemotherapy, the neck nodes were adamant. “The neck nodes were big enough to cause severe pain when touched,” says Dr Sujit. “They were located close to the blood vessel going from the neck to his right hand.”
Radiation was performed on the neck nodes to relieve the pain. It caused the nodes to shrink, giving respite from the pain.
Small cell lung cancer: Rapid growth
“Lung cancer is primarily divided into small cell carcinoma and non-small cell carcinoma based on their appearance under the microscope,” says Dr Sujit. “While most lung cancers are of the non-small cell variant, small cell carcinoma is rare, with a prevalence of around 15%.”
What makes small cell carcinoma peculiar is its ability to grow and spread rapidly.
“By the time a person notices symptoms and attains a diagnosis, 80% of the time the tumor has metastasised or spread to other body parts,” Dr Sujit adds.
Stages of small cell carcinoma
“Small cell carcinoma is divided into two stages depending on the spread: limited stage and extensive stage,” says Dr Udaya Sureshkumar, associate consultant pulmonologist, Hosmat Hospitals, Bengaluru.
Dr Udaya elaborates on the stages:
- Limited stage: The cancer is restricted to one side of the chest — that is, the lung where the cancer originated and the surrounding lymph nodes.
- Extensive stage: The cancer has spread beyond the affected lung to the other lung or lymph nodes of the other lung, and to other organs of the body. There is a greater predisposition to spread to areas like bones, liver, brain and adrenal glands.
Symptoms of oat cell carcinoma
According to Dr Udaya, small cell carcinoma usually begins in the centre of the lung, entering the major airway and causing irritation and obstruction, which leads to cough, breathlessness, chest pain and blood in cough.
“As it progresses further, it can cause complications like pneumonia, infections and recurrent fevers,” she adds.
Dr Sujit says that when the cancer spreads to other organs, the symptoms will correspond to the organ of spread. For instance, if it spreads to the bone, there can be bone pain. If the cancer has metastasised to the brain (brain mets), one may see changes in vision, hearing and seizures.
Facial swelling and puffiness can also be indicators of a growing tumor.
“The tumor obstructs blood flow of the superior vena cava, a vein that carries blood from the head, neck, arms and chest to the heart, causing pressure and swelling in the upper body,” says Dr Udaya. This condition is called superior vena cava syndrome and causes swelling, puffiness of the face, upper lips and neck, she adds.
Diagnosing small cell carcinoma
According to Dr Kamlesh Pandey, consultant chest physician, Wockhardt Hospitals, Mumbai, diagnosis usually happens in the extensive stage. “Diagnosis is done using a tissue biopsy, where a sample of the tissue is removed and studied under the microscope to look for the presence of cancer cells,” he says.
Dr Udaya adds that bronchoscopy, a test to view the airways, and CT scans are also done to diagnose the cancer.
Paraneoplastic syndrome
Paraneoplastic syndrome, which is seen in some people with cancer, is a group of rare conditions caused when the cancer-fighting antibodies mistakenly attack the healthy cells of the nervous system, causing symptoms like muscle weakness and electrolyte disorders.
“The person may initially receive a diagnosis of paraneoplastic syndrome and then, on further evaluations, a lung mass may be spotted, indicating small cell lung cancer,” says Dr Sujit.
Smoking: A major risk factor
“Tobacco smoking is a major risk factor for small cell lung cancer. Over 95% of people with small cell lung cancer have a history of smoking,” says Dr Pandey.
Dr Udaya notes that historically this cancer was more common among men between 60 and 80 years, but the gender gap has narrowed with smoking becoming common among women.
“Women are also more susceptible to the cancerous effects of smoking than men, causing an increasing incidence of lung cancer in women,” says Dr Udaya.
Treating small cell lung cancer
Dr Udaya says the cancer can be surgically removed if it is in the limited stage and if the tumor size is less than 3cm. Chemotherapy with radiation is the primary treatment and can also help reverse cancer in the limited stage.
“In the extensive stage, the cancer cannot be reversed, and the aim of treatment is to improve the quality of life and prolong survival,” Dr Pandey says. Chemoradiation reduces the size of tumor and releases the pressure on the nearby organs.
Another mode of treatment is targeted cell therapy, where the gene that causes the cancer to grow is targeted with antibodies, according to Dr Udaya.
Takeaways
Small cell lung cancer is a rare but aggressive form of lung cancer and is mostly seen in smokers. It is divided into two stages: limited and extensive. Treatment involves surgery, chemoradiation and targeted cell therapy. Typical symptoms are persistent cough, breathlessness, chest pain and blood in cough.
