Abstract P3-03-17: No relationship of axillary total tumor load (TTL) by PCR (OSNA) in early breast cancer and local and distant clinical outcomes
Authors: Tur R , Parra J , Martin R , Alés-Martinez JE 
Published: May 2019

Abstract
BACKGROUND
The study of sentinel lymph nodes (SLN) assessed by One Step Nucleic Acid Amplification (OSNA, Sysmex, Kobe, Japan) creates a new variable, Total Tumor Load (TTL). This variable is defined as the total number of CK19 mRNA copies in all positive SLN (copies/microL). The latest edition of the Spanish Oncological Gynecology Society (SEGO) Guideline (2017) proposes complete axillary lymph node dissection (ALND) when TTL is 15,000 copies or more in early breast cancer. In our center we are using OSNA to ascertain if there is axillary node involvement but the decision to proceed to ALND is based on Z0011 criteria. We want to determine if there is a correlation between clinical outcomes and TTL values, between TTL and pathological variables and if TTL is a useful tool to decide when to complete an ALND.
METHODS
Clinicopathological and follow up data were obtained from all patients with invasive breast cancer and SLN assessed by OSNA between 2011 and end of 2016 at our center.
RESULTS
A total of 277 patients underwent SNB assessed by OSNA with an average follow-up of 56.4 months. 276 were female and 1 male. Age range 27-88 years (mean 58,7). 86,2 % were ductal, 10,8 % lobular and 2,8 % other. 51.9% were luminal A, 51.98% luminal B, 28.51%, triple negative, 5% Her2 positive and 5% luminal B-Her2 positive. TTL was equal to 0 in 155 cases and greater than zero in 122 cases.68 cases showed a TTL higher than 15,000 copies. Only 19 cases met Z0011 criteria and had ALND. As of now, 3 patients have had locoregional relapse (TTL = 0 in 2 cases and 18,000 copies in one) and 5 metastatic disease (none with simultaneous locoregional recurrence). 7 patients have died (one from metastatic breast cancer, 1 febrile neutropenia, 2 septic shock unrelated to chemotherapy, 2 from other tumors, 1 encephalopathy).
BASELINE DATA N=277VARIABLE N%AGE,MEDIAN RANGE 58,7 (27-88) TUMOR TYPEDuctal23986,2 Lobular3010,8 Others82,8IMMUNOPHENOTYPELuminal A14451,98 Luminal B7928,51 Luminal B-HER2145 HER2 positive14 Triple Negative269,3TOTALL TUMORAL LOAD (TTL)=015556 &gt;012244AXILLARY LYMPH NODE DISECTIONS 196,8TTL&gt;15000 6824,5LOCOREGIONAL RELAPSES 31
CONCLUSIONS
1. Using Z0011 criteria, we have adequate clinical outcomes with a very low rate of ALND and locoregional recurrences.
2. If we had based the axillary management on TTL values we would have multiplied the number of ALND by a factor of 2,7 (from 18 to 50).
3. We have observed a tendency to higher TTL in luminal phenotypes and to lower TTL in HER2 positive and triple negative subtypes.
4. Work is in progress to increase our sample size.
Citation Format: Tur R, Parra J, Martin R, Alés-Martinez JE. No relationship of axillary total tumor load (TTL) by PCR (OSNA) in early breast cancer and local and distant clinical outcomes [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-03-17.