Prognostic value of detection mode in over 1000 consecutively treated grade 2 breast cancers

ABSTRACT Background In histological grade 2 BC molecular classification is of high value (JNCI 2006; 98:262), but clinical, pathological and immunohistochemical variables may be useful as well. We here assess the prognostic value of ‘mode of detection’ and ‘palpability’ in grade 2 BC. Patients and methods The disease free interval in all primary operable grade 2 BC from UZ Leuven (01/2000 – 05/2005) was studied. Patients with missing variables (n = 17) were excluded. Univariable and multivariable proportional hazards Cox regression using the Firth's penalization method to reduce bias in the parameter estimates were used. The assessed prognostic variables were age at diagnosis, tumor size, nodal status, BC subtype, method of detection, lobular versus other histology, systemic adjuvant therapy, nuclear grade, architectural grade, mitotic count. Estimated hazard rates (HR) are presented (only for significant variables, see table). Results 1010 patients were included. Median follow-up: 7 years 10 months. 144 events (14.3%) were observed: 52 local and 92 metastatic. In univariable analysis and compared with palpable non-screen detected BC, HR for relapse was 0.34 (95% CI 0.17-0.62) for screen detected not palpable and 0.75 (95% CI 0.49-1.12) for screen detected palpable BC. The beneficial univariable effect of ‘screen detected not palpable’ remained in the multivariable analysis, together with significant prognostic value for lymph node status and BC subtype (see Table 1 ). Table 1 . Multivariable proportional hazards Cox regression Variable HR (95% CI) Positive lymph nodes 0 Reference 1 1.11 (0.63,1.86) 2-4 1.66 (0.97,2.75) >4 3.32 (1.83, 5.85) * NNP vs other 5.63 (1.90, 14.2) Screen and Palpable Non screen - Palpable Reference Screen – Not palpable 0.38 (0.19, 0.70) Screen - Palpable 0.87 (0.56, 1.33) * ER-negative, PgR-negative, HER-2 positive Conclusion Screen-detected not-palpable BCs were found to be independently associated with a better disease free interval among women with a primary operable grade 2 invasive BC. Method of detection should be taken into account when estimating prognosis in early BC. Disclosure All authors have declared no conflicts of interest.