Timing of radiotherapy and survival benefit in breast cancer.
OBJECTIVE
To look at the optimum timing of radiotherapy in breast-conserving therapy (BCT) in relation to outcome in breast cancer.


METHODS
We analyzed 1473 BCT on 1446 breast cancer patients from our prospective cohort, stage I or II, node-negative, and without adjuvant systemic therapy. Timing was defined as time from lumpectomy till radiotherapy. Patients were categorized into three timing tertiles: 1-36 days, 37-53 days, and 54-112 days.


RESULTS
The 10-year local relapse-free survival rates did not show significant differences between the three groups. The 10-year Distant Metastasis-Free Survival (DMFS) was 78.9% for the first tertile, versus 86.1% (HR 0.6; P = 0.009) for the second, and 90.7% (HR 0.3; P < 0.001) for the third. The 10-year Disease-specific Survival (DSS) was 83.8% for the first tertile, versus 90.6% (HR 0.5; P = 0.007) for the second, and 97.2% (HR 02; P < 0.001) for the third. Also in multivariate Cox regression analysis the second (HR 0.6; P = 0.053) and the third tertile (HR 0.3; P = 0.002) had significantly better DSS.


CONCLUSIONS
Timing of radiotherapy in BCT for breast cancer seems to be highly important in relation to survival. This study shows a 40-70% relative survival benefit with timing after 36 days.
Jobsen
Jan J
JJ
Department of Radiation Oncology, Medisch Spectrum Twente, Haaksbergerstraat 55, 7513 ER, Enschede, The Netherlands. j.jobsen@ziekenhuis-mst.nl
van der Palen
Job
J
Ong
Francisca
F
Meerwaldt
Jacobus H
JH
D000328:Adult; D001943:Breast Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D015331:Cohort Studies; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D015412:Mastectomy, Segmental; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018714:Radiotherapy, Adjuvant / Q000379:methods; D013997:Time Factors