Abstract P2-14-12: Impact of the time interval between neoadjuvant chemotherapy and surgery in Latin-Americans breast cancer patients
Authors: Rebaza LP , Galarreta JA , Castañeda C , Cotrina JM , Vilchez S , de la Cruz M , Ponce J , Aguilar A , Flores C , Castillo M , Galvez M , Vigil C 
Published: May 2019

Background: Few studies have evaluated the impact of the time interval between neoadjuvant chemotherapy (NAC) and surgery in breast cancer. In Latin America, where the vast majority of hospitals are oversaturated, it is important to define which patients to give priority and to be clear about ideal time or maximum to schedule surgery after NAC without altering the prognosis. The objective of this work is to establish the ideal time interval for post-neoadjuvant surgery and evaluate the impact on patient survival.

Methods: We reviewed the clinical histories of breast cancer with clinical stage II and III who received NAC between 2005 and 2014. Patients were divided into 3 groups according to the time interval to surgery: &lt;4, 4-8 and &gt;8 weeks. Overall survival (OS) and recurrence-free survival (RFS) were estimated using the Kaplan-Meier method, and comparisons of survival curves using the logrank or Breslow test, both globally and by molecular subtypes. The optimal time to surgery has been determined by the Cox model.

Results: During the study period, 583 patients who had post NA surgery before six months were registered. The median age was 49 years (range: 24-85), 82% had clinical stage III, 53% histological grade III, 32.7% were luminal A, 15.6% luminal B, 24.4% Her2 and 27.3% TN. According to the time interval to surgery, 67 (11.5%) patients had surgery before 4 weeks, 204 (35.0%) between 4 to 8 weeks, and 312 (53.5%) after 8 weeks. The groups do not present differences in relation to the clinical characteristics (p&gt; 0.05). The median follow-up time was 4.8 years. The 5-year OS rate according to the time interval was 57.9, 61.5, and 62.7% (p = 0.581) and the RFS rate was 40.6, 52.3, and 51.1% (p = 0.411). No differences were found in the survival curves by molecular subtypes , except for luminal b like . In the multivariate analysis, the effect of the time interval to surgery was not significant in OS and RFS; however, the HR curve suggests that the appropriate cut-off point for surgical time would be 8 weeks.

Table 1:Time Interval :OS - RFS  RFS  OS  MEDIAN5 - yearsPMEDIAN5 - yearsPWeeks for NAC to Surgery      &lt;4 weeks3.240.6 6.157.9 4-8 weeks6.352.3 9.161.5 &gt;8 weeks5.151.10.416.762.70.581       Weeks for NAC to Surgery      &lt;8 weeks549.5 9.160.7 &gt;8 weeks5.151.10.5856.762.70.414

Table 2 :Time Interval - Molecular Subtype  RFS  OS  MEDIAN5 - yearsPMEDIAN5 - yearsPLUMINAL A LIKE      &lt; 8 weeks----74.1 ----84 &gt;8 weeks7.163.80.719.973.90.236       *LUMINAL B LIKE      &lt; 8 weeks2.336.8 5.460.5 &gt;8 weeks5.857.60.46----820.08       HER2      &lt;8 weeks2.228.7 3.938.4 &gt;8weeks3.645.90.57.26.261.30.616       TRIPLE NEGATIVE      &lt;8 weeks3.144.2 3.448.4 &gt;8 weeks2.041.80.9143.743.90.516* ER + PR &gt;20% KI67&gt;14% , HER2 NEGATIVE

Conclusion: The time interval between the end of neoadjuvant period and surgery has no impact on recurrence-free survival or on overall survival, despite this we suggest that the period of time between neoadjuvant and surgery not be greater than 8 weeks. More studies will be required to determine the ideal time interval and which cases should be prioritized according to the characteristics of our patients.

Citation Format: Rebaza LP, Galarreta JA, Castañeda C, Cotrina JM, Vilchez S, de la Cruz M, Ponce J, Aguilar A, Flores C, Castillo M, Galvez M, Vigil C. Impact of the time interval between neoadjuvant chemotherapy and surgery in Latin-Americans breast cancer patients [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 P2-14-12.