
Clinical assessment

Mammography

Breast ultrasound



ITT (n = 28)

PP (n = 24)

ITT (n = 21)

PP (n = 17)

ITT (n = 27)

PP (n = 23)


Pearson correlation

r = 0.3146

r = 0.4003

r = 0.2396

r = 0.2956

r = 0.2099

r = 0.3188


p = .1030

p = .0526

p = .2955

p = .2494

p = .2934

p = .1382

Spearman correlation

r = 0.3839

r = 0.5092

r = 0.1037

r = +0.0409

r = 0.4111

r = 0.3371


p = .0437

p = .0110

p = .6548

p = .8761

p = .0331

p = .1158

Multiple regression analysis

F = 1.96

F = 1.66

F = 0.87

F = 0.60

F = 0.73

F = 1.05


p = 0.1471

p = 0.2070

p = 0.4748

p = 0.6278

p = 0.5465

p = 0.3928


R^{2} = 0.1967

R^{2} = 0.1996

R^{2} = 0.1334

R^{2} = 0.1212

R^{2} = 0.0866

R^{2} = 0.1424


R^{2}* = 0.0963

R^{2}* = 0.0795

R^{2}* = 0.0195

R^{2}* = 0.0816

R^{2}* = 0.0326

R^{2}* = 0.0070

 * adjusted.
 Threefold statistical analysis performed for clinical tumor assessment, MG, and breast US included: a) Pearson correlation of percent change in tumor size from baseline to Individual End vs. days on letrozole treatment; b) Spearman correlation of tumor response categories (1 = CR to 4 = PD) at Individual End vs. days on letrozole treatment; and c) multiple regression analysis of percent change in tumor size as criterion vs. days on treatment, age, and tumor size at baseline as predictors (3 degrees of freedom). Deviations in ITT and PP population sizes from 29 and 25, respectively, were due to nonanalyzable patients.