Outcomes of Post Mastectomy Radiation Therapy in Patients Receiving Axillary Lymph Node Dissection After Positive Sentinel Lymph Node Biopsy.
We sought to determine the rate of postmastectomy radiation therapy (PMRT) among women treated with axillary lymph node dissection (ALND) after positive sentinel lymph node (SLN) biopsy results and to establish the effect of negative ALND results and PMRT on locoregional recurrence (LRR) and overall survival (OS).



All patients were treated with mastectomy and ALND after positive SLN biopsy results. All patients had clinical N0 or NX disease at the time of mastectomy and received no neoadjuvant therapy. The presence of lymphovascular space invasion, presence of multifocality, number of positive SLNs and non-SLNs, clinical and pathologic stage, extranodal extension, age, and use of PMRT were evaluated for significance regarding the rates of OS and LRR.



A total of 345 patients were analyzed. ALND after positive SLN biopsy results was negative in 235 patients (68.1%), and a total of 112 patients (32.5%) received radiation therapy. On multivariate analysis, only pathologic stage III predicted for lower OS (hazard ratio, 3.32; P<.001). The rate of 10-year freedom from LRR was 87.9% and 95.3% in patients with positive ALND results and patients with negative ALND results, respectively. In patients with negative ALND results with ≥3 positive SLNs, the rate of freedom from LRR was 74.7% compared with 96.7% in those with <3 positive SLNs (P=.009). In patients with negative ALND results, ≥3 positive SLNs predicted for an increase in LRR on multivariate analysis (hazard ratio, 10.10; P=.034).



A low proportion of cT1-2, N0 patients with positive SLNs who undergo mastectomy receive PMRT after ALND. Even in this low-risk cohort, patients with ≥3 positive SLNs and negative ALND results are at increased risk of LRR and may benefit from PMRT.
Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas. Electronic address: mstauder@mdanderson.org.
Michael C
MC
Stauder
Department of Breast Surgical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas.
Abigail S
AS
Caudle
Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas.
Pamela K
PK
Allen
Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas.
Simona F
SF
Shaitelman
Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas.
Benjamin D
BD
Smith
Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas.
Karen E
KE
Hoffman
Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas.
Thomas A
TA
Buchholz
Department of Breast Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas.
Mariana
M
Chavez-Macgregor
Department of Breast Surgical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas.
Kelly K
KK
Hunt
Department of Breast Surgical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas.
Funda
F
Meric-Bernstam
Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas.
Wendy A
WA
Woodward
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla; D001943:Breast Neoplasms / Q000401:mortality* / Q000473:pathology / Q000628:therapy*; D003131:Combined Modality Therapy; D015897:Comorbidity; D005260:Female; D006801:Humans; D008197:Lymph Node Excision / Q000401:mortality* / Q000706:statistics & numerical data; D008408:Mastectomy / Q000401:mortality*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality* / Q000473:pathology / Q000517:prevention & control; D015995:Prevalence; D018714:Radiotherapy, Adjuvant / Q000401:mortality; D020266:Radiotherapy, Conformal / Q000401:mortality*; D012307:Risk Factors; D021701:Sentinel Lymph Node Biopsy / Q000706:statistics & numerical data; D015996:Survival Rate; D013781:Texas / Q000453:epidemiology; D016896:Treatment Outcome