TABLE 3.

Multivariate logistic regression model results for occult primary breast cancer pooled analysis

Regression model outcome/independent variable	Odds ratio (OR)	95 % CI	p value
Receiving breast surgery
Being from Asiaa	5.98	2.02–17.65	0.0012
Receiving radiation therapyb	0.23	0.09–0.59	0.0033
Receiving chemotherapy
Being from Asiac	0.32	0.13–0.82	0.0167
Being from the United Statesd	13.08	2.64–64.78	0.0016
Receiving radiation therapy
Study published ≥ 2004e	3.86	1.41–10.55	0.0084
Receiving breast surgerye	0.23	0.09–0.60	0.0027
Distant/metastatic recurrence
Receiving chemotherapyf	9.77	1.10–87.21	0.0412

CI confidence interval

^aMultivariate logistic regression model included the following variables (variable values in parentheses with reference group italicized): geography (from Asia, not from Asia), year of publication (≥2004, ≤2003), chemotherapy (received, did not receive), radiation therapy (received, did not receive)

^bMultivariate logistic regression model included the following variables (variable values in parentheses with reference group italicized): geography (from United States, not from United States), year of publication (≥2004, ≤2003), chemotherapy (received, did not receive), radiation therapy (received, did not receive). Similar point estimates and CIs obtained from models in which geography variable values were Asia versus Not from Asia and Europe versus Not from Europe

^cMultivariate logistic regression model included the following variables (variable values in parentheses with reference group italicized): geography (from Asia, not from Asia), year of publication (≥2004, ≤2003), breast surgery (received, did not receive), radiation therapy (received, did not receive)

^dMultivariate logistic regression model included the following variables (variable values in parentheses with reference group italicized): geography (from United States, not from United States), year of publication (≥2004, ≤2003), breast surgery (received, did not receive), radiation therapy (received, did not receive)

^eMultivariate logistic regression model included the following variables (variable values in parentheses with reference group italicized): geography (from United States, not from United States), year of publication (≥2004, ≤2003), breast surgery (received, did not receive), chemotherapy (received, did not receive). Similar point estimates and CIs obtained from models in which geography variable values were Asia versus Not from Asia and Europe versus Not from Europe

^fMultivariate logistic regression model included the following variables (variable values in parentheses with reference group italicized): geography (from United States, not from United States), year of publication (≥2004, ≤2003), breast surgery (received, did not receive), chemotherapy (received, did not receive), radiation therapy (received, did not receive). Similar point estimates and CIs obtained from models in which geography variable values were Asia versus Not from Asia and Europe versus Not from Europe