title: Long-term survival of T1 and T2 lymph node-negative breast cancer patients according to Mitotic Activity Index: a population-based study.
abstract: Node-negative breast cancer patients have a relatively good prognosis, but eventually one-third will die of the disease. Thus, prognostic factors to identify the high-risk group among these patients are needed. We retrospectively determined the Mitotic Activity Index (MAI) for a large series of node-negative breast cancer patients (n = 468) with tumours smaller than 5 cm, who only received locoregional treatment. Patients were followed for up to 29 years; crude and relative survival were calculated, both univariate and multivariate. Relative survival differed significantly according to MAI (p = 0.05), the difference occurred in the first 5 years after diagnosis and remained constant thereafter. After adjustment, MAI still significantly affected relative survival (RER, 1.9; 95% CI, 1.1-3.5). Tumour size also increased the risk, but this was not statistically significant (RER, 1.5; 95% CI, 0.8-2.7). Survival of patients with a T1 tumour and MAI < 10 was similar to that for the general population in the first 5 years after diagnosis. In conclusion, MAI significantly predicted long-term survival for T1/T2N0 breast cancer. Adjuvant systemic therapy appears to have little benefit for node-negative breast cancer patients with a T1 tumour, regardless of the MAI. For those with a T2 tumour and a MAI > or = 10 systemic therapy might have reduced mortality. The need for close surveillance of node-negative breast cancer patients with a T1 tumour and MAI < 10 seems limited.
authors.affiliation: Eindhoven Cancer Registry, Comprehensive Cancer Centre South (IKZ), Eindhoven, The Netherlands. research@ikz.nl
authors.forename: W J
authors.initials: WJ
authors.lastname: Louwman
authors.forename: M W P M
authors.initials: MW
authors.lastname: van Beek
authors.forename: R F M
authors.initials: RF
authors.lastname: Schapers
authors.forename: M B C J E Tutein
authors.initials: MB
authors.lastname: Nolthenius-Puylaert
authors.forename: P J
authors.initials: PJ
authors.lastname: van Diest
authors.forename: R M
authors.initials: RM
authors.lastname: Roumen
authors.forename: J W W
authors.initials: JW
authors.lastname: Coebergh
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D008875:Middle Aged; D008940:Mitotic Index; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D016019:Survival Analysis