Purpose: To investigate the relationship between spiculated masses at mammography and marginal adipose tissue invasion at histologic examination.
Materials and methods: The institutional review board approved this retrospective study, and the requirement to obtain informed consent was waived. A total of 478 patients with invasive breast cancer who underwent surgery between 1999 and 2009 were included in this study. Clinical-pathologic findings from patients with spiculated masses on mammograms were compared with those from patients without spiculated masses by using logistic regression models, Cox proportional hazards regression models, and the Kaplan-Meier method.
Results: There were 136 spiculated tumors and 342 nonspiculated tumors. All 136 spiculated tumors (100%) were positive for adipose tissue invasion, whereas only 264 of the 342 nonspiculated tumors (77%) were positive for adipose tissue invasion (P < .001). Multivariate analysis revealed that adipose tissue invasion (P < .001), histologic grade (P < .001), dense breast (P = .002), and body mass index (P = .02) were independent factors associated with spiculation. With regard to survival, although many patients with spiculated tumors had a hormone-sensitive (estrogen receptor positive: P = .004; progesterone receptor positive: P = .001) or low-grade (P < .001) tumor, in contrast to the patients without spiculated masses, the prognosis in the two groups was similar (disease-free survival: P = .09; overall survival: P = .23).
Conclusion: Cancer cell interaction with adipose tissue is crucial for the finding of spiculation at mammography.