Introduction: Various factors affect breast cancer prognosis; however, little information is available regarding the role of primary tumor site. The purpose of this study was to compare the survival and clinicopathologic characteristics of patients with breast cancer by primary tumor location.
Materials and methods: We analyzed a prospectively collected single-institution breast cancer registry. Univariate and multivariable analyses were used to evaluate the association of tumor site with positive lymph node status, presence of metastasis, time to recurrence or death, and events of recurrence or death. Patients with tumors originating from the upper-outer quadrant were the reference group.
Results: From 2003 to 2015, 5295 patients with breast cancer were identified. Tumors originated from the upper-outer quadrant (36.2%), upper-inner quadrant (13.1%), lower-outer quadrant (9.8%), lower-inner quadrant (7.6%), nipple (1.2%), axillary tail (0.3%), or overlapping (24.7%). Tumors originated from overlapping lesions (odds ratio [OR], 1.58; 95% confidence interval [CI], 1.36-1.83) had higher odds of positive axillary lymph nodes, whereas tumors from the upper-inner (OR, 0.68; 95% CI, 0.56-0.84) and lower-inner quadrant (OR, 0.72; 95% CI, 0.56-0.93) had lower odds. Tumors from the lower-outer quadrant were associated with lower risk of death (hazard ratio, 0.64; 95% CI, 0.46-0.88), whereas tumors from overlapping lesions had higher risk (hazard ratio, 1.28; 95% CI, 1.05-1.55).
Conclusion: The site of primary tumor may be an important characteristic affecting the prognosis of patients with breast cancer.
Keywords: Humans; Primary tumor site; Recurrences; Registries; Survival.
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