title: Impact of Tumor Size on Probability of Pathologic Complete Response After Neoadjuvant Chemotherapy.
abstract: BACKGROUND
  The prospective Neoadjuvant Breast Symphony Trial (NBRST) study found that MammaPrint/BluePrint functional molecular subtype is superior to conventional immunohistochemistry/fluorescence in situ hybridization subtyping for predicting pathologic complete response (pCR) to neoadjuvant chemotherapy. The purpose of this substudy was to determine if the rate of pCR is affected by tumor size.
  
  
  METHODS
  The NBRST study includes breast cancer patients who received neoadjuvant chemotherapy. MammaPrint/BluePrint subtyping classified patients into four molecular subgroups: Luminal A, Luminal B, HER2 (human epidermal growth factor receptor 2), and Basal type. Probability of pCR (ypT0/isN0) as a function of tumor size and molecular subgroup was evaluated.
  
  
  RESULTS
  A total of 608 patients were evaluable with overall pCR rates of 28.5 %. Luminal A and B patients had significantly lower rates of pCR (6.1 and 8.7 %, respectively) than either basal (37.1 %) or HER2 (55.0 %) patients (p < 0.001). The probability of pCR significantly decreased with tumor size >5 cm [p = 0.022, odds ratio (OR) 0.58, 95 % confidence interval (CI) 0.36, 0.93]. This relationship was statistically significant in the Basal (p = 0.026, OR 0.46, 95 % CI 0.23, 0.91) and HER2 (p = 0.039, OR 0.36, 95 % CI 0.14, 0.95) subgroups. In multivariate logistic regression analyses, the dichotomized tumor size variable was not significant in any of the molecular subgroups.
  
  
  CONCLUSIONS
  Even though tumor size would intuitively be a clinical determinant of pCR, the current analysis showed that the adjusted OR for tumor size was not statistically significant in any of the molecular subgroups. Factors significantly associated with pCR were PR status, grade, lymph node status, and BluePrint molecular subtyping, which had the strongest correlation.
authors.affiliation: Department of Surgery, Breast and Melanoma Specialists of Charleston, Charleston, SC, USA. baronpl@gmail.com.
authors.forename: Paul
authors.initials: P
authors.lastname: Baron
authors.affiliation: Department of Surgery, Dallas Surgical Group, Dallas, TX, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Beitsch
authors.affiliation: Department of Biostatistics, Levine Cancer Institute, Charlotte, NC, USA.
authors.forename: Danielle
authors.initials: D
authors.lastname: Boselli
authors.affiliation: Department of Biostatistics, Levine Cancer Institute, Charlotte, NC, USA.
authors.forename: James
authors.initials: J
authors.lastname: Symanowski
authors.affiliation: Department of Surgery, Virginia Breast Center, Bon Secours Cancer Institute, Richmond, VA, USA.
authors.forename: James V
authors.initials: JV
authors.lastname: Pellicane
authors.affiliation: Department of Surgery, The Breast Place, Charleston, SC, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Beatty
authors.affiliation: Department of Surgery, Blue Ridge Cancer Care, Roanoke, VA, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Richards
authors.affiliation: Department of Surgery, Coastal Carolina Breast Center, Murrells Inlet, SC, USA.
authors.forename: Angela
authors.initials: A
authors.lastname: Mislowsky
authors.affiliation: Department of Surgery, Northeast Georgia Medical Center, Gainesville, GA, USA.
authors.forename: Charles
authors.initials: C
authors.lastname: Nash
authors.affiliation: Department of Surgery, Comprehensive Cancer Center, Palm Springs, CA, USA.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Lee
authors.affiliation: Department of Surgery, Akron General Hospital, Akron, OH, USA.
authors.forename: Mary
authors.initials: M
authors.lastname: Murray
authors.affiliation: Department of Medical Affairs, Agendia Inc, Irvine, CA, USA.
authors.forename: Femke A
authors.initials: FA
authors.lastname: de Snoo
authors.affiliation: Department of Medical Affairs, Agendia Inc, Irvine, CA, USA.
authors.forename: Lisette
authors.initials: L
authors.lastname: Stork-Sloots
authors.affiliation: Department of Surgery, Breast Care Specialists, Allentown, PA, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Gittleman
authors.affiliation: Department of Surgery, Virginia Hospital Center, Arlington, VA, USA.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Akbari
authors.affiliation: Department of Surgery, Nashville Breast Center, Nashville, TN, USA.
authors.forename: Pat
authors.initials: P
authors.lastname: Whitworth
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D014408:Biomarkers, Tumor; D001943:Breast Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007124:Immunoenzyme Techniques; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012074:Remission Induction; D015996:Survival Rate; D047368:Tumor Burden; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human