Anatomical distribution of small cell lung cancer: effects of lobe and gender on brain metastasis and survival.
BACKGROUND
Primary small cell lung cancer (SCLC) has a predilection for the right rather than the left lung. The aim of this study was to examine the association between gender and pulmonary location and to examine the effects of these variables on the incidence of brain metastasis and the survival rate of patients with SCLC.


METHODS
We conducted a retrospective review of medical charts of patients diagnosed with SCLC between January 1989 and December 2002 at MeritCare Hospital in Fargo, ND, USA. The effects of the anatomical site of SCLC, age, gender, body mass index, stage of SCLC and treatment of SCLC on the incidence of brain metastasis and survival were examined using univariate and multivariable Cox proportional-hazards regression models.


RESULTS
Two-hundred and thirty patients were identified with SCLC. One hundred and forty-eight (64%) were male and 82 (36%) were female. SCLC was significantly more common in the right upper lobe for females (51%) than for males (32%) (p-value=0.005) and in the left upper lobe for males (28%) compared to females (11%) (p-value=0.003). Survival was significantly longer in both younger patients (48 weeks vs. 26 weeks; log-rank p-value=0.03) and female patients (50 weeks vs. 36 weeks; log-rank p-value=0.01). The multivariable Cox model showed an adjusted HR of 1.52 (95% confidence interval 1.01-2.3) for the right lung relative to the left lung. We found no impact of anatomical distribution or pulmonary location on the incidence of brain metastasis.


CONCLUSIONS
In these data, SCLC is more common in the right upper lobe for females. Right lung and male gender are associated with a worse prognosis, which may suggest that more aggressive therapy is needed in these patients.
Sahmoun
Abe E
AE
University of North Dakota School of Medicine, Fargo, ND 58102, USA. asahmoun@medicine.nodak.edu
Case
L Douglas
LD
Santoro
Thomas J
TJ
Schwartz
Gary G
GG
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000473:pathology / Q000556:secondary*; D018288:Carcinoma, Small Cell / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012737:Sex Factors; D015996:Survival Rate