Postmastectomy electron-beam-rotation irradiation in locally advanced breast cancer prognostic factors of locoregional tumor control.
BACKGROUND
Different radiotherapy techniques are used for postmastectomy irradiation. We review the results with the electron-beam-rotation technique in advanced breast cancer patients. Main endpoint was local tumor control.


METHODS
From 1990 to 1998 119 patients with adverse pathology features (pT3 17% of patients, pT4 42%, multicentricity 36%, pN >/= 3 positive nodes and/or pN1biii 81%, close margins 30%) underwent electron-beam-rotation irradiation of the chest wall with daily fractions of 2.0-2.5 Gy per day to 50 Gy total dose after modified radical mastectomy and axillary lymph node dissection. A local boost of 10 Gy and/or irradiation of locoregional lymph nodes were applied depending on the completeness of resection and lymph node involvement.


RESULTS
After a median follow-up of 73 months for patients at risk the 5-year local tumor control, local tumor control first event, disease-free, and overall survival were 82%, 92%, 57%, and 63% (Kaplen Meier analysis), respectively. Significant predictors of poor local tumor control were maximal tumor diameter >/= 5 cm (p = 0.01), "close margins" or residual tumor (p < 0.01), four or more involved axillary lymph nodes (p = 0.02), two or more involved lymph node levels (p = 0.04), negative estrogen receptor status (p = 0.03), and high-grade histopathology (GIIb-III, p < 0.01). The subgroup analysis showed a high local failure rate of 37% for high-grade (GIIb-III) and estrogen receptor negative tumors, whereas no local recurrence was found in low-grade (GI-Iia) and receptor positive tumors (p = 0.01). The multivariate analysis revealed maximal tumor diameter >/= 5 cm, four or more involved axillary lymph nodes and high-grade histopathology (GIIb-III) as independent predictors of poor local tumor control.


CONCLUSIONS
In high-risk breast cancer patients postmastectomy irradiation with the electron-beam-rotation technique is an effective therapy, resulting in a 5-year local failure rate of 8%. Intensified local therapy needs further investigation in subgroups of patients with additional risk factors.
Hehr
Thomas
T
Department of Radiation Oncology, University of Tuebingen, Germany. Thomas.Hehr@med.uni-tuebingen.de
Budach
Wilfried
W
Durst
Ilona
I
Glocker
Stefan
S
Classen
Johannes
J
Weinmann
Martin
M
Christ
Gunter
G
Bamberg
Michael
M
D001943:Breast Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D003131:Combined Modality Therapy; D019583:Dose Fractionation, Radiation; D004583:Electrons / Q000627:therapeutic use*; D005260:Female; D005858:Germany; D006801:Humans; D008197:Lymph Node Excision; D015182:Lymphatic Irradiation; D008207:Lymphatic Metastasis; D015411:Mastectomy, Modified Radical; D009367:Neoplasm Staging; D011379:Prognosis; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies; D012307:Risk Factors; D016019:Survival Analysis