Background:It is well known that mammographic screening reducesbreast cancer mortality. One possible explanation for this effect is thatscreening makes it possible to detect smaller breast cancers with fewerinvolved nodes, but another hypothesis is that some screening-detected tumorsare in a pathologically and biologically different phase of evolution fromthose that are detected clinically. The aim of the present study was tocompare the biological, pathological and clinical characteristics ofsymptomatic vs. asymptomatic breast cancers.
Patients and methods:The study considers a series of 1916consecutive patients who underwent surgery for stage I and II infiltratingbreast cancer at Verona hospitals after having undergone ultrasound andmammography (at least one of which was positive). They were divided into twogroups on the basis of why they decided to undergo the imaging examinations:group A refers to the 1247 patients with a palpable lump, and group B to the616 who were asymptomatic.
Results:The patients in group A were older, and had larger tumorsand a higher percentage of positive nodes than those in group B; they also hadsignificantly higher grade tumors, higher Ki-67 levels, and a higherpercentage of ER and PgR negative and c-erbB-2 positive tumors (allof the P-values were significant). A logistic regression analysisadjusted for tumor diameter and age showed a reduction in the significance ofeach of the considered variables, but all of them remained significantlyassociated with the modality of diagnosis except ER, PgR andc-erbB-2.
Conclusions:Our results suggest that asymptomatic tumors arebiologically different from their clinically presenting counterparts, thusconfirming the hypothesis that progression towards greater malignancy mayoccur during the natural history of breast cancer.