Introduction
The only proven strategy to fight any form of cancer is early detection based on evidence and researchers. Based on current evidence, low-dose computed tomography (CT) is highly recommended for patients with high risk for lung cancer. Many researchers state the potential advantages of CT screening in such patients over conventional screening methods. The American Cancer Society and American Lung Cancer Association, early detection and CT screening is one of the best and only proven methods to fight lung cancer across all age groups. In the US, Lung Cancer is the lead cause of cancer-associated death with an alarming morbidity rate. In the US, 3 out of 4 patients have incurable lung cancer that is locally advanced and metastatic in nature. Most of the cases are advanced due to delayed diagnosis. Stage IV lung cancer is known to have a less than 5% chance of a 5-year survival rate. However, the survival rate can increase by up to 53% if the lung cancer is detected at an early stage followed by surgical removal. Furthermore, only 15% of patients are diagnosed at an early stage. Most patients benefit from low-dose CT which is at an early stage for lung cancer. Based on the report by the U.S. Preventive Services Task Force, most of the patients who benefit from early stage low-dose CT screening are between 55 and 88 years old with a history of smoking in the past 15 years or currently smoking. These patients have either smoked a pack per day in the past 30 years of 2 packs a day in the past 15 years (Marcus, P. M. 2015; Marshall, H. M., et al. 2013; and O’Brien, M. E. 2014).
Aim: With a keen interest in radiological sciences, radiological diagnostics, and Imaging Sciences, I would like to pursue a doctorate degree in Screening for Lung Cancer. The doctorate degree would help me enhance my knowledge in lung cancer screening since I have a strong academic background radiological sciences coupled with a broad experience in nuclear medicine. My vision is to utilize my expertise and knowledge to serve public health and improvise the quality of human life (Christensen, J. D., & Tong, B. C. 2013).
Review of Literature
Lung cancer is known to form in the inner cells of lungs, usually the tissues and linings of the air passages. There are two types of lung cancer based on cell physiology, small cell lung cancer and non-small-lung cancer. The type of lung cancer is confirmed upon microscopic evaluation of the cells. Lung cancer can be treated easily if diagnosed at an early stage before it spreads to other parts of the body. However, in most cases, lung cancer is known to have spread beyond the lung when diagnosed in over 25% of cases. As mentioned by the WHO, lung cancer is the prime cause of cancer related mortality in the US and the world. In more than 80% of lung cancer cases, patients are cigarette smokers. Based on the WHO and CDC, there are more than 90 million smokers in the US itself. Smokers are at a high probability of developing lung cancer (Islami, F., Torre, L. A., & Jemal, A. (2015).
Screening and Lung Cancer
Screening forms a crucial part in the control and effective management and treatment of diseases. It also helps in analysing lung cancer in asymptomatic conditions. The primary aim of early diagnosis is to detect the disease at an early and treatable stage. However, screening tests and examinations are often widely accepted by healthcare professionals only after it meets the set criteria. One of the main criteria of most screening methods includes reduction in the mortality rate due to early and precise detection of the disease. Screening examinations often include laboratory examinations that evaluate blood and fluids. Precise tests also include genetic testing in order to confirm any genetic links to cancer. Imaging tests help healthcare practitioners in assessing pictures inside the body. Most of the tests are readily available for the public. However, there are specific tests that are based on an individual’s requirements such as gender, family history, and age (Detterbeck, F. C., et al. 2013; Marshall, H. M., et al. 2013; and O’Brien, M. E. 2014).
Screening modalities are dependent on the medical condition of an individual. For individuals with asymptomatic conditions of lung cancer and a high risk of developing the disease are recommended low-dose computed tomography (LDCT) screening of the chest. The principle of CT scanning is based on the use of combined x-ray modalities along with computer technology to produce a series of high quality images of organs of the body. On the other hand, LDCT is known to produce good quality images that would help in detecting many lung disease. It also helps in assessing and diagnosing any abnormalities in the underlying cells of the lungs. Compared to a conventional chest CT scan, LDCT utilizes 90% lower ionizing radiation (Marshall, H. M., et al. 2013).
My keen interest in lung cancer screening and utilizing low-dose CT and helping patients for early stage detection. My thesis would include the potential of low-dose CT in the diagnosis of lung cancer in order to reduce the morbidity and mortality of lung cancer. One of the prime reasons for opting for the doctoral degree is to assess the potential of CT screening with respect to detection of nodules, patient safety and comfort, radiation risks involved, side-effects (if any), and image quality. These keep factors would help in assessing the potential benefits and risks of CT screening for lung cancer. Furthermore, my research would also include analysis of various types of CT scans available and the time taken for each patient (scanning, analysis, and report generation) in order to detect lung cancer (Detterbeck, F. C., et al. 2013 & Marshall, HM, et al. 2013)
Method
I am keen interest in radiological sciences and would like to enhance my knowledge in lung cancer screening using CT. Based on current evidence, I have found that CT screening is similar to that of x-ray examinations. They are a type of radiation that pass through the required body part after guidance. Based on the examination, x-rays vary differently.
CT scanning is a sophisticated screening method wherein many x-ray joist along with a series of x-ray detection equipment are rotated around the body to assess the amount of radiation absorbed by the body. However, within the same period, the investigational table is rotating in such a distinct way that it passes through the scanner allowing the x—ray beam to follow a spiral pathway. The best method to detect early stage lung cancer is CT screening that helps in detecting pulmonary nodules that are around 3 to 5 mm in diameter. In order to accurately detect such nodules, a thin slice CT examination of around 1mm is recommended. The thin slices are known to generate around 300 axial slices per scan which is mainly recommended by a thoracic radiologist. However, the entire process is known to be time-consuming with a high rate of missing nodules. Based on current evidence, a radiologist would now utilize assisted computer-aided detection (CAD) tools to detect missing nodules.
Based on my experience and expertise with respect to radiological sciences, I would cater to over 20 patients a day. I would ideally utilize low-dose CT for patients at high risk for lung cancer. Other modalities for lung cancer screening include chest x-ray and sputum cytology. 2-D images of the body are produced with the help of a sophisticated computerized program. The images are displayed on the screen and such a technique is known as spiral or helical CT. In the case of a chest X-ray, an experienced technologist would place the patient flat on his/her back (in some case on one side or on the stomach). In order to maintain the perfect position for an accurate diagnosis, pillows and straps are used in order to remain still throughout the examination. In most cases, the patients are asked to move their arms above their shoulders. In order to determine an accurate beginning position for the scan, the examination table would move swiftly through the scanner. Once the position is established, the table would enter into the scanner (Christensen, J. D., & Tong, B. C. 2013).
Screening Analysis
The most common form of lung cancer is that of a lung nodule which is a round lesion found in the abnormal tissue of the lungs. However, more than 93% of the nodules do not indicate cancer but a characteristic features of tissue scarring and past infection of the lymph nodes. Most medical practitioners would recommend a second round of LDCT if the first round recognizes a nodule. However, the later would confirm cancer diagnosis if there is abnormal growth of the nodules. Furthermore, doctors would not make the final diagnosis of lung cancer unless (PET) is conducted.
Based on current CT screening guidelines, I would assess the pulmonary nodules based on site and size. If upon examination with low-dose CT, the nodule size is >5mm, it is recommended to send it across to pathological examination. However, if the nodule size is <5mm upon low-dose CT screening, an annual screening of the same is recommended.
Based on the recommended guidelines, the nodules of the thin-section CT scan are classified into three types which are as follows: Solid nodule, mixed GGO, and pure GGO type. Low-dose CT is recommended at intervals of 3,6,9, and 12 months if the initial size of the nodule is found to be >10mm. The same is recommended if an intra-pulmonary nodule is detected upon initial scan. The entire process is recommended for individuals with a solid type nodule. In the case of mixed GGO type, CT scans ideally present pneumonia and a 3-month follow up for the same is recommended. If the size of the nodule remains unchanged or reduces over a span of 3 months, low-dose CT scan is still recommended. In the case of a pure GGO type, if the size of the nodule is >15mm, follow-up CT is recommended at 3, 6, 9, and 12 months. However, if there is an increase in the density and size of the nodule, 24-month follow-up CT is recommended. In order to utilize the low-dose CT screening for optimal results with respect to image size and quality, single size and multi-size CT is recommended.
The PET imaging maybe preceded or followed by a cell biopsy. It is easy to analyse a biopsy and confirm if the cells are malignant or benign. If the path lab test confirms cancerous nodules, further serological and visual tests are conducted. These tests would help in determining the phase of the tumour (Christensen, J. D., & Tong, B. C. 2013). Lastly, the imaging tests often conducted to confirm the diagnosis of lung cancer include CT along with a series of bone scans with or without PET/CT scan. The therapy or treatment of lung cancer is dependent on the stage, gender, and age of the individual (Gutierrez, A., et al. 2013; Christensen, J. D., & Tong, B. C. 2013; and Detterbeck, F. C., et al. 2013).
Figure 1. Scanning and Reconstruction Protocol for Multisite CT
Figure 2. Exposure Dose
Thus, with an extensive academic background in radiological sciences and diagnostics, coupled with board certifications from The American Registry of Radiologic Technologists (ARRT) and Nuclear Medicine Technology Certification Board (NMTCB) and Board Certified Positron Emission Tomography Technologist by NMTCB, I would like to pursue a doctorate degree in CT screening for lung cancer.
References
Christensen, J. D., & Tong, B. C. (2013). Computed Tomography Screening for Lung
Cancer:: Where Are We Now? North Carolina Medical Journal, 74(5), 406–410.
Detterbeck, F. C., Mazzone, P. J., Naidich, D. P., & Bach, P. B. (2013). Screening for Lung
Cancer: Diagnosis and Management of Lung Cancer, 3rd ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest, 143(5 Suppl), e78S–e92S. http://doi.org/10.1378/chest.12-2350
Gutierrez, A., Suh, R., Abtin, F., Genshaft, S., & Brown, K. (2013). Lung Cancer Screening.
Seminars in Interventional Radiology, 30(2), 114–120. http://doi.org/10.1055/s-0033-1342951
Islami, F., Torre, L. A., & Jemal, A. (2015). Global trends of lung cancer mortality and
smoking prevalence. Translational Lung Cancer Research, 4(4), 327–338. http://doi.org/10.3978/j.issn.2218-6751.2015.08.04
Marcus, P. M. (2015). Lung cancer screening with low dose computed tomography (LDCT):
looking back and moving forward. Annals of Translational Medicine, 3(Suppl 1), S41. http://doi.org/10.3978/j.issn.2305-5839.2015.03.36
Marshall, H. M., Bowman, R. V., Yang, I. A., Fong, K. M., & Berg, C. D. (2013). Screening
for lung cancer with low-dose computed tomography: a review of current status. Journal of Thoracic Disease, 5(Suppl 5), S524–S539. http://doi.org/10.3978/j.issn.2072-1439.2013.09.06
O’Brien, M. E. (2014). Lung cancer screening: Is there a future? Indian Journal of Medical
and Paediatric Oncology : Official Journal of Indian Society of Medical & Paediatric Oncology, 35(4), 249–252. http://doi.org/10.4103/0971-5851.144984
