Basal phenotype: a powerful prognostic factor in small screen-detected invasive breast cancer with long-term follow-up.
OBJECTIVE
To assess the frequency and prognostic significance of a basal phenotype in a group of women with screen-detected invasive breast cancers with long-term follow-up and to focus particularly on women with small ( < 15 mm) breast cancers.


METHODS
The study group was derived by finding women common to a consecutive series of 1944 invasive breast cancers diagnosed in Nottingham between 1986 and 1998 with a known basal phenotype status and a prospectively collected database of all screen-detected breast cancers. In total, 356 women constituted the study group. Pathological and radiological features were recorded. Basal cell markers used were CK5/6 (cloneD5/16134) and CK14 (clone LL002). Tumours were classified as of basal phenotype if > or = 10% staining was seen with either marker.


RESULTS
Of all screen-detected lesions, 43 (12%) had a basal immunophenotype and 313 (88%) were non-basal. There were 15 (35%) and 40 (13%) breast cancer deaths in the basal group and nonbasal groups, respectively ( P = 0.0006). On univariate analysis, nodal stage, histological grade, lympho-vascular invasion (LVI) status, invasive size and basal phenotype had prognostic significance. On multivariate analysis, basal phenotype, LVI and nodal stage maintain prognostic significance. Of the 189 women with < 15 mm lesions, eight of 20 (40%) of the basal group and eight of 169 (5%) of the non-basal group died of breast cancer ( P < 0.0001). On multivariate analysis, basal phenotype was the only factor to maintain independent prognostic significance.


CONCLUSIONS
Basal phenotype is a powerful prognostic factor for women with small screen-detected invasive breast cancer.
Evans
A J
AJ
Radiology, Breast Institute, Nottingham City Hospital, Nottingham, UK. andrew.evans@nuh.nhs.uk
Rakha
E A
EA
Pinder
S E
SE
Green
A R
AR
Paish
C
C
Ellis
I O
IO
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000401:mortality / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D053547:Keratin-14 / Q000032:analysis; D053555:Keratin-5 / Q000032:analysis; D053553:Keratin-6 / Q000032:analysis; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D010641:Phenotype; D011379:Prognosis; D012042:Registries; D016019:Survival Analysis; D013997:Time Factors
D053547:Keratin-14; D053555:Keratin-5; D053553:Keratin-6