Abstract P6-06-23: Glycogen-rich, clear cell breast cancer - An underestimated histopathological risk factor?

Abstract

Abstract Introduction: Glycogen-rich clear cell carcinoma (GRCCC) is a rare tumour and there is only few data on the prognosis of this subtype, the largest cases series ever published in literature comprising of 21 cases only. (1) Patients and methods: In a case-control study of 56 GRCCC early breast cancer cases with matched pairs we analyzed the features of this subtype and survival data regarding DFS and OS. 56 patients with GRCCC have been identified from the period 1992 until 2010 in a multicenter retrospective case cohort trial. To determine the incidence of glycogen-rich clear cell carcinoma in various age groups were stratified in 3 age groups: < 45 years, < 65 years and > 65 years. This was compared to incidence of all breast cancer subtypes due to epidemiological data of Robert-Koch-Institute of the German Ministry of Health. Results: Patients were in a range of 33-87 years, median 59,5 years, distributed to the following age groups: 14% (n = 8) of patients were < 45 years, 71,4% (n = 40) < 65 years and 28,6% (n = 16) > 65 years. In the epidemiological data set 10% were < 45 years, 50% < 65 years and 50% > 65 years. Thus patients with glycogen-rich clear cell carcinoma were younger compared to the epidemiological data of all breast cancers registered nationally (< 65 years: 71,4% vs. 50%; p < 0,002). Stage distribution was as follows: Stage T1 a: no cases, T1b: 2, T1c: 19, T2: 20, T3: 4, T4: 4, unknown T-stage in 7 cases. Nodal status was in 22 nodal-positive, 23 nodal-negative and 11 with unknown nodal status. The Grading was in G1 none, G2 24 and G3 29 and unknown in 3 cases. Approximated intrinsic tumour subtype was: Luminal A: 10, Luminal B 3, Luminal Her2 positive 16, non-luminal Her2 negative: 14, Triple-Negative Breast Cancer: 7; not further specified: 6. Chemotherapy was applied in 35 out of 56 patients (62,5%) in our study cohort. 5-years-(OS) was 84% and 5-years (DFS) was 80%. Recurrence rates at a mean time of follow-up of 8,5 years were significantly higher (11 recurrences out of 56 cases) in this specific subtype than in the matched control group (p<0,005). OS was significantly lower in the group with a local recurrence, dropping down from a 5-years OS-rate of 92% in the recurrence-free group to 48% in the group with a loco-regional recurrence. Conclusion: GRCCC of the breast is associated with a highly proliferative and aggressive receptor profile and unfavourable course of disease with significantly higher risk of recurrence (p< 0,005). This is - to our best knowledge - the largest cohort published in literature on this rare histological subtype of human early breast cancer. Evidence derived from this analysis suggests effective chemotherapy treatment to reduce the risk of recurrence and mortality from this aggressive tumour subtype. The poor prognosis of 48% in 5-years-overall-survival in case of a loco-regional recurrences of glycogen-rich clear cell carcinom also endorses a role of chemo-therapy in case of recurrence, with regards to the fact that survival rates in this tumor subtype of our cohort were even lower than in the cohort of the CALOR trial.(2) Literature: 1) Hayes MMM, Am J Surg Pathol. 1995;19:904-911. 2)Aebi S, S3-2. San Antonio Breast Cancer Symposium 2012. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-06-23.