ESMO Asia Virtual Congress 2020

Abstract 27P

Background

Breast cancer prognostic factors vary from pathological grades, hormonal sensitivity, stage and LN metastasis. Results from recent studies discuss primary location as survival indicator but its significance still unclear. With SEER database registry in place, a rich source for data collection with differentiating breast cancer sites and primary location. With analysis of these data, the effect of cancer's primary origin on breast cancer survivorship would be more comprehensive.

Methods

Using SEER*stat 8.3.6 program, Based on Incidence - SEER Research Data, 9 Registries, Nov 2019 Sub (1975-2017), patients diagnosed with breast cancer (site recode ICD-O-3) between 1975-2017 are selected. Case listing session was done with extraction patients year of diagnosis, survival time in months, laterality, and primary site. Cox regression was done using IBM SPSS statistics 25. p-value <0.001 is considered significant.

Results

720272 patients were involved in analysis (50.9% left:49.1% right origin of primary). Median survival time for the cohort was 185 months(95% CI:184.4:185.5). Left side malignancy showed a significantly less positive effect on survival than right originated ones (HR, 0.988; 95% CI, 0.982–0.995). The upper and lower inner quadrants show a significantly higher effect on survival (HR, 1.877; 95% CI, 1.797–1.960) and 1.761(1.685). (HR, 1.761; 95% CI, 1.685–:1.842) respectively P-value <0.001. Table: 27P

	P-value	HR	95.0% CI for HR
Lower	Upper
Nipple	Reference
Central portion of breast	<0.001	1.454	1.391	1.521
Upper-inner quadrant of breast	<0.001	1.877	1.797	1.960
Lower-inner quadrant of breast	<0.001	1.761	1.685	1.842
Upper-outer quadrant of breast	<0.001	1.567	1.501	1.635
Lower-outer quadrant of breast	<0.001	1.711	1.637	1.788
Axillary tail of breast	<0.001	1.142	1.078	1.211
Overlapping lesion of breast	<0.001	1.680	1.610	1.754
Breast, NOS	<0.001	1.350	1.293	1.410

Hazard ratios for primary site of breast cancer: Cox regression analysis Optimal cut-offs were determined with a maximal chi-square method.HR: hazard ratio; CI: confidence interval; NOS: not otherwise specified

Conclusions

Upper and lower inner quadrants show the best survival for patients diagnosed with breast cancer. The primary site of malignancy in breast cancer appears to be a good predictive value of survival and can be used as a rough method to predict patients` prognosis. More Data extraction, analysis, and interpretation of overall and cause-specific survival are recommended for more knowledge about the primary site in depth.