Abstract P4-02-03: Cancer phenotype is the key factor in axillary involvement and distant recurrence in early breast cancer
Authors: Alés-Martínez José Enrique , Tur Raquel , Parra Juan , De Castro Ana , Ceballos Jaime , Martín Rocío , Marcos Rosa Ana , Blanco Paz , Velasco MJose 
Published: March 2020

BACKGROUND: Factors by which breast cancer cells invade blood and lymphatic capillaries and metastasize regional lymph nodes and distant sites are not well understood. Genetics, molecular subtype, epidemiological, mechanical and pathological factors are being considered. Once breast cancer cells invade lymphatic or blood vessels the route of spread is still unclear. Cells could access the systemic circulation through the sentinel lymph node or directly avoiding the lymph node step. Molecular subtype is one of the most important factors associated with the risk of metastases. Our objective is to determine the influence of immunophenotype and the sentinel lymph node (SLN) status to predict the risk of locoregional relapses and distant metastases in early breast cancer. In our center we are using a molecular technique (OSNA) to ascertain if there is sentinel lymph node involvement, this technique creates a new continuous variable, Total Tumor Load (TTL), defined as the total number of CK19 mRNA copies in all positive SLN (copies/microL), indicating the total tumor volume of axillary tumor involvement.

METHODS: Clinicopathological and follow up data were obtained from all patients with early breast cancer treated with Tumorectomy (Tx) and Sentinel Lymph Node (SLN) assessed by OSNA with the decision to proceed to ALND based on Z0011 criteria and systemic therapy between 2011 and 2018 at our center (J Clin Oncol 37, 2019 (suppl; abstr 564))

RESULTS: 304 breast cancer patients underwent Tx and SLN assessed by OSNA followed by systemic therapy with an average follow-up of 64.9 months. SLN was positive in 122 cases and negative in 182. SLN negative patients were Luminal A (LA) 58%, Luminal B (LB) 14%, HER2 10% and Triple-Negative (TN) 7%. SLN positive patients were LA 52%, LB 35%, HER2 7% and TN 5%. Mean TTL was 136,244 copies (see table). As of now, 11 patients have had recurrence (locoregional relapse and distant disease): 6 of them with positive SLN (54,54%) and 5 with negative SLN (45,45%). A total of 4 patients have had locoregional relapse, two of them with negative SLN (50%) both non luminal tumors (1 HER2, 1 TN), and 7 have had distant disease, three of them with negative SLN (43%). Only one patient has died from metastatic breast cancer (HER2 positive, SLN negative).

CONCLUSIONS:

1. In our series, almost half of the patients (45%) with recurrence were negative SLN.

2. The probability of recurrence when the sentinel lymph node is negative is higher in HER2 and TN tumors (60%).

3. The probability of recurrence when the SLN is positive is higher in luminal tumors (66,6%).

4. Luminal tumors with positive SLN and large volume axillary involvement (median 1.419.450 copies) have a higher probability of recurrence (statistically significant) than luminal tumors with positive SLN and small volume axillary involvement (median 131.479 copies).

PATIENTS AND OUTCOMES

VARIABLE N=304Number of cases (n,%)Median age, range (years)LOCOREGIONAL RELAPSEMETASTASIC BREAST CANCEREXITUSMean TTL with NO recurrenceMean TTL with recurrencePOSITIVE SLN122 (40%)59,8 (33-87)2 (1,63%)4 (3,27%)0By ImmunophenotypeLuminal A64 (52,4%)59,3 (36-87)1 (1,5%)2 (3,1%)0371.5592.838.333Luminal B43 (35,2%)59,5 (36-84)1 (2,32%)00258.6221600HER29 (7,3%)61 (33-80)01 (11,1%)021.582640Triple Negative6 (5%)59,6 (50-80)01 (16,6%)0108.181184.000NEGATIVE SLN182 (60%)59,3 (27-89)2 (1,09%)3 (1,64%)1 (0,5%)By ImmunophenotypeLuminal A106 (58%)59,3 (33-82)000Luminal B43 (14,1%)59,5 (36-89)1 (2,32%)1 (2,32%)0HER219 (10,4%)59,3 (40-82)01 (5,2%)1 (5,2%)Triple Negative14 (7,7%)59,4 (27-85)1 (7,14%)1 (7,14%)0

Citation Format: José Enrique Alés-Martínez, Raquel Tur, Juan Parra, Ana De Castro, Jaime Ceballos, Rocío Martín, Rosa Ana Marcos, Paz Blanco, MJose Velasco. Cancer phenotype is the key factor in axillary involvement and distant recurrence in early breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-02-03.