Advanced Oncology Certified Nurse Practitioner (AOCNP) Certification Practice Test

Which type of lung cancer accounts for 75-80% of SIADH cases?

1. Non-small cell lung cancer

2. Small cell lung cancer

3. Squamous cell carcinoma

4. Adenocarcinoma

The correct answer is: Small cell lung cancer

Small cell lung cancer is associated with the development of the paraneoplastic syndrome known as Syndrome of Inappropriate Antidiuretic Hormone secretion (SIADH). This syndrome arises when cancer cells produce antidiuretic hormone (ADH) or similar substances, leading to water retention and electrolyte imbalances, particularly hyponatremia. Small cell lung cancer typically has a more aggressive clinical course and a higher correlation with paraneoplastic syndromes than other types of lung cancer. It occurs more frequently in patients with a history of heavy smoking and can progress rapidly, emphasizing the need for vigilant monitoring for complications such as SIADH. In contrast, while non-small cell lung cancer can also lead to paraneoplastic syndromes, it does not account for as significant a proportion of SIADH cases as small cell lung cancer. Similarly, squamous cell carcinoma and adenocarcinoma, being subtypes of non-small cell lung cancer, exhibit a lower incidence of SIADH compared to small cell lung cancer. This distinction highlights the specific role of small cell lung cancer in the development of SIADH among lung cancer types.