Proliferation accurately identifies the high-risk patients among small, low-grade, lymph node-negative invasive breast cancers.
BACKGROUND
The proliferation factor mitotic activity index (MAI) is the strongest prognosticator in lymph node-negative invasive breast cancer patients under age 71. The question remains, whether this also holds for 'favourable prognosis' subgroups.


METHODS
The study was a multicentre prospective analysis of the MAI for recurrence-free survival and overall cancer-related survival of grade, MAI, and other prognosticators in 853 long-term follow-up, T1-3N0M0 breast cancer patients under 71 years.


RESULTS
In all tumours together (N = 853), in grade 3 (n = 269), in tumours <1 cm all grades (n = 84), 1-2 cm, grades 1 + 2 (n = 300), and 2-3 cm, grades 1 + 2 (n = 124), the MAI is prognostically superior. Other features [grade, estrogen receptor (ER), diameter, and age] did not enhance its prognostic value except in grades 1 + 2 tumours 2-3 cm diameter with MAI <10, where ER has an additional prognostic value.


CONCLUSIONS
In women <71 years with T1-3N0M0 small or low-grade invasive breast cancer usually not receiving systemic treatment, MAI > or =10 accurately identifies those at high risk. These high-risk patients should be considered for adjuvant systemic therapy.
Baak
J P A
JP
Department of Pathology, VU University Medical Center, Amsterdam, The Netherlands. baja@sus.no
van Diest
P J
PJ
Janssen
E A M
EA
Gudlaugsson
E
E
Voorhorst
F J
FJ
van der Wall
E
E
Vermorken
J B
JB
D000328:Adult; D000367:Age Factors; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D001943:Breast Neoplasms / Q000737:chemistry / Q000401:mortality / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000737:chemistry / Q000401:mortality / Q000473:pathology*; D049109:Cell Proliferation; D015986:Confounding Factors, Epidemiologic; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008875:Middle Aged; D008940:Mitotic Index; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D011960:Receptors, Estrogen / Q000032:analysis; D018570:Risk Assessment; D012307:Risk Factors
D014408:Biomarkers, Tumor; D011960:Receptors, Estrogen