Ectopic corticotropin syndrome and small-cell carcinoma of the lung. Clinical features, outcome, and complications.
BACKGROUND
Ectopic corticotropin syndrome is a rare complication of small-cell lung cancer (SCLC). There is little information concerning this syndrome available in the literature. We therefore reviewed all cases of ectopic corticotropin syndrome seen at our institution during a 20-year period.


METHODS
Cases were identified by searching a computerized database and reviewing the charts of all 840 patients with SCLC seen between 1971 and 1991. Patients were included if they met at least two of the following criteria: spontaneous hypokalemia (potassium level, < 3.2 mmol/L); plasma cortisol level greater than 600 nmol/L; 24-hour urinary free cortisol level greater than 400 nmol/d; and plasma corticotropin level greater than 22 pmol/L. Data were abstracted from the patients' medical records.


RESULTS
Of 840 patients with SCLC, 14 (1.6%) had ectopic corticotropin production. This was diagnosed at the time of presentation with SCLC in seven patients and from 3 to 19 months later in the remainder. Five patients had limited disease and nine had extensive disease. One or more features of Cushing's syndrome were observed in 57% of patients, but the entire syndrome occurred rarely. Spontaneous hypokalemia was present in all patients, and 10 patients (71%) had hyperglycemia. There were two complete responses and one partial response to chemotherapy, giving an overall response rate of 21%, and the median survival was 5.5 months. Ten patients died of progressive growth of tumor, while three patients died of infections. In one other patient, infection probably contributed to death. A high rate of nonfatal infections was also seen.


CONCLUSIONS
The occurrence of SCLC with ectopic corticotropin syndrome is associated with poor survival, and a high incidence of infective complications, in patients treated with chemotherapy.
Department of Medicine, Princess Margaret Hospital, Toronto, Ontario.
L
L
Delisle
M J
MJ
Boyer
D
D
Warr
D
D
Killinger
D
D
Payne
J L
JL
Yeoh
R
R
Feld
D000182:ACTH Syndrome, Ectopic / Q000209:etiology*; D000328:Adult; D000368:Aged; D018288:Carcinoma, Small Cell / Q000188:drug therapy / Q000378:metabolism*; D003480:Cushing Syndrome / Q000209:etiology; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D016896:Treatment Outcome