Primary tumor and patient characteristics in breast cancer as predictors of adjuvant therapy regimen: a regression model.
OBJECTIVE
Adjuvant therapy reduces the risk of recurrence of breast cancer. This study was undertaken to determine characteristics guiding choice of adjuvant therapy.


METHODS
A retrospective review was completed of characteristics of patients with breast cancer (stages I-III) at a regional center from 2004 to 2007. Univariate analysis was used to select factors (P < 0.1) for entry into multivariate stepwise logistic regressions. Odds ratios with 95% confidence intervals were calculated. A P value of <0.05 was significant, and comparisons were two-tailed.


RESULTS
Model 1 (n = 744) assessed the prescription of any adjuvant regimen (hormonal or chemotherapy). Indicators of choice of any regimen were positive lymph nodes [OR 16.5, CI (6.2, 44.0)], grade [4.0, (2.5, 6.0)], size [3.2, (2.1, 4.6)], PR [0.3, (0.1, 0.6)], and multicentricity [0.2 (0.04, 0.66)]. Model 2 (n = 663) assessed chemotherapy in ER+ patients. Indicators of addition of chemotherapy were stage [8.9 (4.3, 18.6), grade [5.5 (3.1, 9.6)], positive nodes [2.7 (1.1, 6.4)], physician experience [1.1 (1.0, 1.2)], age [0.8 (0.79, 0.86)], and year of treatment [0.8, (0.4, 0.9)]. Model 3 (n = 867) assessed prescription of a more aggressive chemotherapy regimen and indicators were treatment by a breast specialist oncologist [8.6 (1.7, 43.1)], stage [3.6 (2.4, 5.4)], positive nodes [2.6 (1.7, 4.1)], year of treatment [1.5 (1.3, 1.8)], size [1.2 (1.1, 1.4)], age [0.91 (0.89, 0.93)], and PR [0.4 (0.3, 0.6)].


CONCLUSIONS
This study verifies known factors for choice of adjuvant therapy, excludes others thought to be important, and quantifies effects at our center. Further studies are required to compare these models where risk stratification is different.
Department of Surgery, McMaster University, Hamilton, ON, L8L 2X2, Canada.
Valerie
V
Francescutti
Forough
F
Farrokhyar
Richard
R
Tozer
Barbara
B
Heller
Peter
P
Lovrics
Graham
G
Jansz
Kamyar
K
Kahnamoui
D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology; D000970:Antineoplastic Agents / Q000627:therapeutic use; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D047072:Aromatase Inhibitors / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D017024:Chemotherapy, Adjuvant; D003131:Combined Modality Therapy; D003430:Cross-Sectional Studies; D005260:Female; D006728:Hormones / Q000627:therapeutic use; D006801:Humans; D016015:Logistic Models; D008198:Lymph Nodes / Q000473:pathology; D008875:Middle Aged; D015233:Models, Statistical; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control; D016017:Odds Ratio; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism; D012044:Regression Analysis; D012189:Retrospective Studies; D018570:Risk Assessment; D013629:Tamoxifen / Q000627:therapeutic use
D000970:Antineoplastic Agents; D018931:Antineoplastic Agents, Hormonal; D047072:Aromatase Inhibitors; D006728:Hormones; D011960:Receptors, Estrogen; D013629:Tamoxifen