The key difference between small cell and non small cell lung cancer is in their origin. The small cell lung cancer is a type of lung cancer arising from the neuroendocrine cells whereas the non-small cell lung cancer arises due to varied reasons and has three main varieties based on the origin; the squamous cell carcinoma, adenocarcinoma and large cell carcinoma. Carcinomas is the medical term for serious invasive cancer of epithelial origin.
Lung cancers are one of the commonest malignancies with a high rate of incidence and account for millions of deaths annually all around the globe. Smoking is identified as the main risk factor for lung cancers, but it is not the sole contributory factor. These cancers can be divided into two broad categories as small cell cancers and non-small cell cancers. Small cell cancers arise from neuroendocrine cells and are therefore associate with different paraneoplastic syndromes. The non small cell cancers have three main subtypes; the squamous cell cancers, adenocarcinomas, and large cell cancers. Squamous cell cancers and adenocarcinomas originate from the epithelial cells and glandular tissues respectively, but the origin of large cell cancers cannot be ascertained because they are poorly differentiated.
CONTENTS
1. Overview and Key Difference
2. What is a Small Cell Lung Cancer
3. What is a Non Small Cell Lung Cancer
4. Similarities Between Small Cell and Non Small Cell Lung Cancer
5. Side by Side Comparison – Small Cell vs Non Small Cell Lung Cancer in Tabular Form
6. Summary
What is a Small Cell Lung Cancer?
Small cell carcinomas are a type of lung cancers arising from the neuroendocrine cells. They usually occur in the central regions of the lungs and are associated with early metastasis.
Since they arise from the neuroendocrine cells, they secrete different hormones.
What is Non Small Cell Lung Cancer?
There are three main varieties of non-small cell carcinomas such as squamous cell carcinoma, adenocarcinoma, and large cell carcinoma.
Squamous Cell Cancers
Squamous cell cancers arise from the epithelial cells and are associated with keratin production. The tumor can cavitate and often causes airway obstruction along with post obstructive infections.
Adenocarcinomas
Adenocarcinomas arise from the mucus-secreting glandular cells. These are the commonest type of lung cancers among nonsmokers. They usually develop in the peripheral zones of the lungs.
Figure 01: Non Small Cell Cancer
Large Cell Carcinoma
Large cell carcinomas are often poorly differentiated and metastasize in their early stage.
What are the Similarities Between Small Cell and Non Small Cell Lung Cancer?
Etiological Factors – all the types of lung cancers share common etiological factors which include the followings,
- Smoking
- Exposure to radiatio
- Asbestos
- Aromatic hydrocarbons
- Exposure to chemicals such as arsenic
Host factors – such as immunodeficiency and chronic lung diseases have also been identified as risk factors for both lung cancers.
Clinical Features – although there are different varieties of lung cancers, they all have a similar clinical picture,
- Symptoms due to the local spread- cough, dyspnea, hemoptysis, chest pain, hoarseness of voice, recurrent chest infections, pleural effusions
- Symptoms due to metastatic spread-Generalized pruritus, jaundice, bleeding manifestations, intractable backache, recent onset seizures, early morning headache.
Investigations – the set of investigations below are done for the diagnosis of lung cancers,
- Chest x-ray
- CT
- MRI
- PET
- Bronchoscopy
- Endobronchial USS
Management of lung cancers – in the early stages of the lung cancers, surgery remains as the most effective curative therapy. Radiotherapy has also been proven effective in curing early-stage lung cancers. Palliative care is considered for the advanced malignancies or when the patient is unfit to undergo surgery.
What is the Difference Between Small Cell and Non Small Cell Lung Cancer?
Small cell carcinomas are a type of lung cancers arising from the neuroendocrine cells. On the other hand, there are three main varieties of non- small cell carcinomas based on their origin; namely, squamous cell carcinoma, adenocarcinoma, and large cell carcinoma. They arise due to varied reasons. This is the key difference between small cell and non small cell lung cancer.
Moreover, another difference between small cell and non small cell lung cancer is that the small cell carcinomas usually associate with paraneoplastic manifestations. But, on the contrary, it is rare for the non small cell carcinomas to have paraneoplastic manifestations.
Summary – Small Cell vs Non Small Cell Lung Cancer
There are two main groups of lung cancers as small cell carcinomas and large cell carcinomas. There are three subtypes of non-small cell cancers like squamous cell cancers, adenocarcinomas, and large cell carcinomas. Small cell carcinomas arise from the neuroendocrine cells. Squamous cell carcinomas and adenocarcinomas originate from the epithelial cells and glandular tissues respectively, but the origin of large cell cancers cannot be ascertained because they are poorly differentiated. This is the main difference between these groups of lung cancers.
Reference:
1. Kumar, Parveen J., and Michael L. Clark. Kumar & Clark clinical medicine. Edinburgh: W.B. Saunders, 2012. Print. Ser. 8.
Image Courtesy:
1.’2168601′ by janekszy46 (CC0) via pixabay
2.’33372380900′ by Oregon State University (CC BY-SA 2.0) via Flickr