Effect of Time Interval between Breast-Conserving Surgery and Radiation Therapy on Outcomes of Node-Positive Breast Cancer Patients Treated with Adjuvant Doxorubicin/Cyclophosphamide Followed by Taxane

Abstract

PurposeThis study evaluated the effect of surgery-radiotherapy interval (SRI) on outcomes in patients treated with adjuvant radiotherapy (RT) after breast-conserving surgery (BCS) and adjuvant four cycles of doxorubicin/cyclophosphamide (AC) followed by four cycles of taxane.Materials and MethodsFrom 1999 to 2007, 397 eligible patients were diagnosed. The effect of SRI on outcomes was analyzed using a Cox proportional hazards model, and a maximal chi-square method was used to identify optimal cut-off value of SRI for each outcome.ResultsThe median SRI was 6.7 months (range, 5.6 to 10.3 months). A SRI of 7 months was the significant cut-off value for distant metastasis-free survival (DMFS) and disease-free survival (DFS) using a maximal chi-square method. For overall survival, a significant cut-off value was not found. The patients with SRI > 7 months had worse 6-year DMFS and DFS than those with SRI ≤ 7 months on univariate analysis (DMFS, 81% vs. 91%, p=0.003; DFS, 78% vs. 89%, p=0.002). On multivariate analysis, SRI > 7 months did not affect DMFS and DFS.ConclusionRT delayed for more than 7 months after BCS and adjuvant four cycles of AC followed by four cycles of taxane did not compromise clinical outcomes.

How Does the Interval Between Completion of Adjuvant Chemotherapy and Initiation of Radiotherapy Impact Clinical Outcomes in Operable Breast Cancer Patients?

“… 14 In a retrospective study of 397 patients, TTR after surgery of >7 months was associated with significantly compromised 6-year DFS (78% vs. 89%, p = 0.002) and DRFS (81% vs. 91%, p = 0.003) on univariate analysis, but such significances were missing on multivariable analysis. 15 Significant differences in DRFS and DFS were consistently observed in our study across the TTR after surgery groups on univariable analysis, but no significant impact was retained after adjusting for potential confounders on multivariate analysis. Intervals between surgery and RT depends on various patient-, tumor-, and treatment-related factors.…”

Saving the Breast Saves the Lives of Breast Cancer Patients

“…is supports the evidence that receiving radiation or not could be considered as an independent variable. e time of radiation therapy after surgery is another challenging issue, which is not approved in many independent studies [40][41][42][43]. In a trial with 16 years follow-up, RT confirmed no increased risk of local recurrence when administered 2, 4, and 7 months after surgery and initial systemic therapy [44].…”

Timing of Chemotherapy and Radiotherapy Following Breast-Conserving Surgery for Early-Stage Breast Cancer: A Retrospective Analysis

“…The addition of paclitaxel to anthracycline-based regimens was associated with better local control for node-positive disease ( 16 ). One study showed no effect on clinical outcomes of delaying radiotherapy for more than 32 weeks after BCS and completing four adjuvant cycles of doxorubicin/cyclophosphamide and four cycles of taxane ( 17 ). A study from the MD Anderson Cancer Center also showed no significant difference in recurrence-free survival between patients with node-negative disease who started radiotherapy < 25 weeks and ≥ 25 weeks after BCS when chemotherapy was delivered ( 25 ).…”

“…To address the imbalance of potential confounders of pretreatment variables, one-to-one patient matching without replacement was performed to pair cohorts of each group with a caliper size of 0.001 by propensity-score matching (PSM). We also used the Maxstat method to identify the optimal cut-off value of SCIT for outcomes ( 17 ). Statistical analyses were performed using SPSS Statistics v25.0 (IBM Corp., Armonk, NY, United States) and the “Maxstat” and “Matching” packages in R v3.4.4 1 .…”

“…As for sequential treatment, only one small randomized trial has yet evaluated the effect of sequencing radiotherapy and chemotherapy with an anthracycline-based regimen in breast cancer after BCS, and found no significant differences in the rates of freedom from any adverse event or death (11). In addition, retrospective studies demonstrated inconsistent findings owing to a heterogeneous population in terms of patient characteristics, chemotherapy regimens, and radiation techniques (12)(13)(14)(15)(16)(17). Improvements in both chemotherapy and radiotherapy, such as taxane-based chemotherapy and hypofractionated radiotherapy, have changed early breast cancer treatment practice (16,18).…”