Study of failure pattern among high-risk breast cancer patients with or without postmastectomy radiotherapy in addition to adjuvant systemic therapy: long-term results from the Danish Breast Cancer Cooperative Group DBCG 82 b and c randomized studies.
OBJECTIVE
Postmastectomy radiotherapy (RT) in high-risk breast cancer patients can reduce locoregional recurrences (LRRs) and improve disease-free and overall survival. The aim of this analysis was to examine the overall disease recurrence pattern among patients randomly assigned to receive treatment with or without RT.


METHODS
A long-term follow-up was performed among the 3,083 patients from the Danish Breast Cancer Cooperative Group 82 b and c trials, except in those already recorded with distant metastases (DM) or contralateral breast cancer (CBC). The end points were LRR, DM, and CBC, and the follow-up continued until DM, CBC, emigration, or death. Information was selected from medical records, general practitioners, and the National Causes of Death Registry. The median potential follow-up time was 18 years.


RESULTS
The 18-year probability of any first breast cancer event was 73% and 59% (P < .001) after no RT and RT, respectively (relative risk [RR], 0.68; 95% CI, 0.63 to 0.75). The 18-year probability of LRR (with or without DM) was 49% and 14% (P < .001) after no RT and RT, respectively (RR, 0.23; 95% CI, 0.19 to 0.27). The 18-year probability of DM subsequent to LRR was 35% and 6% (P < .001) after no RT and RT, respectively (RR, 0.15; 95% CI, 0.11 to 0.20), whereas the probability of any DM was 64% and 53% (P < .001) after no RT versus RT, respectively (RR, 0.78; 95% CI, 0.71 to 0.86).


CONCLUSIONS
Postmastectomy RT changes the disease recurrence pattern in high-risk breast cancer patients; fewer patients have LRR as first site of recurrence, and overall fewer patients have DM.
Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus C, Denmark. hmn@oncology.dk
Nielsen
Hanne M
HM
Overgaard
Marie
M
Grau
Cai
C
Jensen
Anni R
AR
Overgaard
Jens
J
D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001365:Axilla; D001943:Breast Neoplasms / Q000473:pathology / Q000628:therapy*; D017024:Chemotherapy, Adjuvant; D003131:Combined Modality Therapy; D003520:Cyclophosphamide / Q000627:therapeutic use; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use; D005500:Follow-Up Studies; D006801:Humans; D008197:Lymph Node Excision; D008408:Mastectomy; D008727:Methotrexate / Q000627:therapeutic use; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology / Q000517:prevention & control*; D009367:Neoplasm Staging; D018714:Radiotherapy, Adjuvant; D012306:Risk; D013629:Tamoxifen / Q000008:administration & dosage; D017211:Treatment Failure
D013629:Tamoxifen; D003520:Cyclophosphamide; D005472:Fluorouracil; D008727:Methotrexate