Answer 3
- SIADH/SCLC.
SIADH is most commonly associated with SCLC. While only 1% to 5% of lung cancer patients have symptomatic SIADH, combination chemotherapy can lead to resolution of SIADH in more than 80% of patients with SCLC.1 Hypercalcemia typically occurs as a result of bony metastases and is most commonly associated with squamous cell carcinoma.2 Ectopic Cushing’s syndrome results from uncontrolled secretion of adrenocorticotropic hormone (ACTH) and its precursors from nonpituitary tissue. Lung tumors account for approximately half of all cases of ectopic Cushing’s syndrome, and a majority are attributed to ACTH production by SCLC cells.11 Unfortunately, most patients with Cushing’s syndrome from SCLC present with extensive disease and have a poor response to chemotherapy.1 LEMS develops through autoimmune mechanisms almost exclusively associated with SCLC. Effective chemotherapy in SCLC patients with neurologic paraneoplastic syndromes such as LEMS may result in improvements in neurologic symptoms.1 Hypertrophic pulmonary osteoarthropathy and digital clubbing are most frequently associated with non–small cell lung cancer (NSCLC), primarily the adenocarcinoma subtype.12 The exact mechanism for this syndrome is unknown, although contributory mechanisms may include neurogenic, hormonal, and vascular pathophysiologies.1
REFERENCES
1. Mazzone PJ, Arroliga AC. Endocrine paraneoplastic syndromes in lung cancer. Curr Opinion Pulm Med 2003;9:313–20.
2. Beckles MA, Spiro SG, Colice GL, Rudd RM. Initial evaluation of the patient with lung cancer: symptoms, signs, laboratory tests, and paraneoplastic syndromes. Chest 2003;123(1 Suppl):97S–104S.
11. Spiro SG, Gould MK, Colice GL; American College of Chest Physicians. Initial evaluation of the patient with lung cancer: symptoms, signs, laboratory tests, and paraneoplastic syndromes: ACCP evidenced-based clinical practice guidelines (2nd edition). Chest 2007;132(3 Suppl):149S–160S.
12. Sridhar KS, Lobo CF, Altman RD. Digital clubbing and lung cancer. Chest 1998;114:1535–7.
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