Clinical Presentation of Lung Cancer

Abstract

Radiation therapy’s goal is to eliminate the tumor mass, while sparing the surrounding healthy organs. Lung cancer is the leading cause of cancer death in the United States. This increase in cancer death is related to the significant use of tobacco related products. The primary routes of spread are through the lymphatic system and direct extension into surrounding organs. Lung cancer consists of three types: adenocarcinoma, squamous cell carcinoma, and large cell carcinoma.

Keywords: Radiation therapy, lung cancer, lymphatic system

Radiation therapy uses ionizing radiation to treat and destroy cancer cells. Radiation therapy’s goal is to destroy the tumor while sparing the healthy, surrounding tissues. Lung cancers are the most common invasive malignancy in the United States. In this clinical presentation, the information will show how lung cancer takes place within the body and how to treat.

Clinical Presentation

The patient in this case is a 53 – year-old African American lady, who was diagnosed with metastatic non-small cell lung cancer in January with presentation of chest pain and shortness of breath. CT chest scan from January 2019 demonstrated a mass in the right lower lobe, suspicious for malignancy. Patient had a lung biopsy, and pathology returned as adenocarcinoma with neuroendocrine differentiation. The patient has been receiving systemic therapy with Carboplatin. A recent rescan from May showed worsening of the disease in the chest. Patient is symptomatic with right chest pain. Patient has decreased appetite, fatigue, and cough. The patient is a heavy smoker, with no history of alcohol use. The patient has no family history of any types of cancer. Due to the extent of the disease, palliative radiation will be administered for 3-4 weeks at 30 Gy.

Epidemiology of Lung Cancer

Lung cancer is the leading cause of cancer death in the United States. Almost as many Americans die of lung cancer every year than die of prostate and breast combined (Cruz, Tanoue, & Matthay, 2011). According to the American Cancer Society, for the year 2019 about 228,150 new cases of lung cancer will be diagnosed and about 142, 670 deaths from lung cancer (2019). Lung cancer mainly occurs in older people around the age of 65, even though the average age of diagnosis is 70.

Etiology

The most common cause of lung cancer is significant tobacco exposures. For example, smoking more than one pack per day would be a significant exposure. The risk for lung cancer increases with the duration of smoking and the number of cigarettes smoked per day. (Cruz et al. 2011). Other forms of tobacco use, such as cigar and pipe smoking have been linked to an increase in lung cancer. This risk seems less than with cigarette smoking. In addition, exposure to secondhand smoke can increase chances of lung cancer. Lung cancer can also be related to occupational exposure, such exposures could include coal tar, nickel, chromium, and arsenic (Stinson & Lahaniatis, p. 623, 2016).

Pertinent anatomy & patterns of spread

The respiratory system consists of the nose, pharynx, larynx, trachea, and both lungs. The trachea begins at the inferior border of the larynx and extends to T5, where the trachea bifurcates into the carina (Washington and lever). At the bifurcation, the trachea branches into left and right bronchii. These bronchii direct air in the lungs. Within the lungs, the bronchii divide into small bronchioles, which the air flows from bronchioles into alveoli. The left lung contains two lobes, whereas the right contains three lobes. The hilum of the lung is the area in which the blood, lymphatics, and nerves enter and exit each lung. Around the alveoli, there are tiny capillaries. The lining of the capillaries is so thin that oxygen and carbon dioxide can move between the capillaries and alveoli. Carbon dioxide diffuses from the capillaries into the alveoli and is released from the body during exhalation (“Lung Cancer”, 2018). Oxygen diffuses in the opposite direction, from the alveoli into the blood, and is carried throughout the body by the circulatory system. (“Lung Cancer”, 2018).

The primary routes of spread for lung cancer are through the lymphatic vessels and direct extension. Involvement of the lymphatics tends to follow the flow of the bronchial tree within the lungs. The spread initially begins in the intrapulmonary nodes, then follows into the hilar nodes. The channel then flows to the mediastinal nodes and ultimately to the supraclavicular nodes.

With direct extension, the tumor mass can continue to grow and invade structures, such as, other parts of the lung, ribs, heart, esophagus, and vertebral column. Tumors that aren’t encapsulated have the ability to attach to structures, such as, the chest wall, diaphragm, and pericardium. (Hsu, Caluwe, Anderson, Nichol, Toriumi,& Ho, 2017).

Detection & diagnosis

When identifying if a person is experiencing symptoms that could indicate lung cancer, there are several diagnostic tests available to confirm the diagnosis. The principal method of lung cancer detection is a conventional x-ray. Other imaging modalities helpful for diagnosis, CT scan and PET scan, which might reveal areas of lung tissue with cancer. Bone scans can also indicate cancerous growth (p. 626). CT scans are often crucial in determining sites for biopsy. PET scans are frequently used for determining whether lesions are malignant of benign based on their metabolic activity. In addition to imaging, laboratory studies should be performed to evaluate complete blood count, serum calcium, alkaline phosphatase, lactic dehydrogenase, and serum glutamic oxaloacetic transaminase values. For surgery, to determine the tumor histology, a flexible bronchoscope can be used in diagnosis and management of lung cancer. The bronchoscope can obtain a specimen for biopsy of remove a foreign body (p628). A mediastinoscopy can be used as well to visualize and examine the mediastinum ( p 628).

Histopathology

The different types of lung cancer are classified by non-small cell and small cell lung cancer, while about 85% are non-small cell lung cancer. There are three major types of non-small cell lung cancer: adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. Squamous cell carcinoma occurs more centrally in the proximal bronchi and caused by tobacco consumption. Adenocarcinoma are located more peripherally, arising in bronchioles or alveoli. Small and large cell carcinomas represent the remaining 20% of lesions. Small cell carcinomas are more centrally located, and large cell carcinomas appear more peripherally. Small cell lung cancer is prone to spread early, and fewer than 10% are diagnosed. (p 628).

Simulation and treatment

Patients with lung cancer are simulated in the supine position with their arms above their head using an immobilization device. The immobilization device ensures that the patient is setup accurately for each treatment. After CT images are taken, thoracic structures are outlined. The lung structures become the combined lung and is used to evaluate the V20. (w/l 634)

The treatment plan is based off the tumor size, location, and stage. For 3D radiation therapy, has the potential to deliver high dose radiation around 70 Gy to the primary tumor while sparing the healthy, surrounding organs. A 4D radiation therapy, which includes respiratory motion, integrates techniques to account for movement during breathing. Sterotactic Body Radiation Therapy is an image guided approach that uses multiple beams to deliver high doses of radiation, in fewer fractions compared to traditional dose.

For treating lung cancers, there are different ranges of dose. Pre-operative doses range from 45-50 Gy in 1.8-2.0 fractions. Definitive radiation ranges from 60-70 Gy in 1.8-2.0 fractions. Post-operative doses range from 50-54 Gy in 1.8-2.0 fractions to the tumor bed.

Assessment and management of side effects

Each patient responds to radiation therapy treatments differently, and it is important to monitor and assess the patient daily before and after treatment. Short term side effects may show up within the first few weeks of treatment, while long term side effects can appear months of even years after treatment.

Some short-term side effects could be skin irritation around the treatment area, fatigue, esophagitis (inflammation of esophagus), or a cough. To manage these short-term effects, it is important to educate the patient on self-care. For skin irritation, Aquaphor can relieve any redness or dry skin, but the patient cannot apply before treatment. Encourage the patient to rest and consume proper nutrition. For esophagitis, if it’s difficult for the patient to eat, enough Ensure or Boost drinks for nutrition supplementation. Some long-term side effects include radiation pneumonitis, pulmonary fibrosis, cardiac toxicity, and secondary cancers. For these side effects, it is important to continue follow ups with physician, so these issues can be prevented.

In conclusion, lung cancer continues to be prominent disease that takes the lives of many people each year. Research should continue in finding a cure for lung cancer due to the increasing number of people who smoke, and earlier age of smoking. As a future radiation therapist, this provides insight to educate and to treat the patients with lung cancer.

References

• Dela Cruz, C. S., Tanoue, L. T., & Matthay, R. A. (2011, December). Lung cancer: Epidemiology, etiology, and prevention. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3864624/
• Hsu, F., Caluwe, A. D., Anderson, D., Nichol, A., Toriumi, T., & Ho, C. (2017). Patterns of spread and prognostic implications of lung cancer metastasis in an era of driver mutations. Current Oncology,24(4), 228. doi:10.3747/co.24.3496
• Lung Cancer. (2018). Retrieved from https://www.cancerquest.org/patients/cancer-type/lung-cancer#anatomy-of-the-lungs