P1-08-11: Differences in Recurrence Dynamics between Lobular and Ductal Invasive Breast Cancer.

Abstract

Abstract Introduction: Many studies investigated disease free survival after breast cancer treatment. A few studies focused on patterns of recurrence risk over time. However, they ignored the impact of histology. This study aimed to determine differences in recurrence dynamics on population-based data between patients with a ductal breast cancer (DBC) and lobular breast cancer (LBC). Methods: All surgically treated women diagnosed in 2003–2004 with invasive DBC or LBC, with no distant metastases or second primary breast cancer were selected from the Netherlands Cancer Registry. The recurrence patterns were studied using the life-table method to estimate the hazard rate for the first recurrence with the worst prognosis (locoregional (LRR) or distant metastases), that is, the conditional probability of manifesting recurrence in a time interval, given that the patient is clinically free of any recurrence at the beginning of the interval. The wilcoxon test was used to determine differences in recurrence patterns between DBC and LBC. Results: Of 16,231 women identified, 87% had DBC and 13% LBC. LRR was found in 4% of the DBC and in 3% of the LBC patients, whereas metastases were found in 11% and 10% of patients, respectively. Notably, in DBC patients a peak in recurrence rate was seen between 1–2 years after diagnosis, both for LRR and distant metastases. On the other hand, in LBC patients the recurrence pattern did not show major peaks: after 2 years the curve revealed an almost steady level for LRR and distant metastases. This recurrence pattern was significantly different (P=<0.001). Moreover, the influence of age, stage and treatment on recurrence differed between DBC and LBC. We also noticed a difference in localization of metastasis. Conclusion: Our study showed an overall equal number of recurrences after DBC and LBC, but with a totally different recurrence pattern, which could have implications on follow-up of the patients. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-08-11.