Radiotherapy or Surgery of the Axilla after a Positive Sentinel Node in Breast Cancer

The AMAROS trial:
- Randomized 4806 clinically node-negative women with T1 to T2 tumors to:
  - Completion axillary lymph node dissection (ALND) or axillary radiation (AR) if they had positive nodes
- Of the 1425 patients with positive sentinel nodes:
  - 744 had been randomly assigned to ALND
  - 681 to AR
- Initially:
  - Patients with tumors 3 cm or smaller were eligible, but the protocol was later modified to include:
    - Tumors up to 5 cm, multifocal tumors, or both
- In the AR arm:
  - 21% of patients had T2 lesions
- There were no age limits for eligibility:
  - Patients ranged from age 48 to 64 years.
- In the AR arm:
  - 42% of women were premenopausal
- Patients who had either partial or total mastectomy were enrolled in the trial:
  - 18% of women had mastectomy
- There was no limit on the number of positive nodes for the radiation arm:
  - But the majority of patients had 1 or 2 positive nodes:
    - 95% of patients having only 1 to 2 positive sentinel nodes
- Crossover was allowed for patients:
  - With extensive axillary disease from the radiation arm to the dissection arm
  - And in the dissection arm who had 4 or more positive nodes were allowed to have axillary radiation
- Four percent of patients who stayed in the radiation arm:
  - Had 3 positive nodes
- One percent of patients who stayed in the radiation arm:
  - Had 4 or more positive nodes
- Importantly:
  - In the axillary dissection arm 25% of patients had an additional 1 to 3 positive nodes (in addition to the positive sentinel nodes) at dissection, and 8% had 4 or more additional positive nodes:
    - Since it was a randomized trial:
      - We can assume the same numbers were present in the radiation arm:
        
        So these patients did not necessarily have low-volume axillary disease.
- Axillary radiotherapy (RT) included:
  - The contents of all three levels of the axilla and the medial part of the supraclavicular fossa
  - The prescribed dose was:
    - 25 fractions of 2 Gy each
- For patients in the AR arm who had mastectomy:
  - Radiation to the chest wall in addition to the axilla was optional but not mandatory
- There were no significant differences in 5-year overall survival or disease-free survival between the two arms
- At 6.1 years of follow-up:
  - There was no significant difference in the rate of axillary failure:
    - 0.43% ALND vs 1.19% RT
- At 5-year follow-up there was a significant difference in:
  - Clinical signs of lymphedema between the groups:
    - 23% in ALND vs. 11% in AR
      - There was greater than a 10% difference in arm size compared to the contralateral arm in:
        
        13% of the ALND arm and 5% of the AR arm
The AMAROS study findings would suggest that axillary RT is an appropriate alternative to ALND in patients with a positive sentinel node:
- However, the clinical characteristics of the AMAROS cohort are remarkably similar to the American College of Surgeons Oncology Group (ACOSOG) Z0011 cohort:
  - With 80% of AMAROS patients having a tumor less than 2 cm
  - 90% patients receiving any systemic therapy
  - 95% of patients having only 1 to 2 positive sentinel nodes
- Patients in ACOSOG Z0011 treated with sentinel lymph node biopsy only demonstrated similar 5-year rates of regional recurrence as the AMAROS patients receiving axillary RT:
  - 0.9% [ACOSOG Z0011] vs 1.19% [AMAROS – AR Arm]
- Thus, while AMAROS indicates that sentinel node biopsy and nodal RT is an alternative to ALND:
  - It does not demonstrate that RT is necessary in all patients with a positive sentinel node, particularly in those treated with breast-conserving surgery.
  - The decision to include axillary RT in patients with 1 to 2 positive sentinel nodes should be tailored to the individual taking into account other clinical factors which may place the patient at higher risk for locoregional recurrence

👉Rodrigo Arrangoiz MS, MD, FACS es cirujano oncólogo experto en mamá y es miembro de la Sociedad Quirúrgica S.C en el Hospital ABC en la Ciudad de México:   

👉Es un experto en el manejo del cáncer de seno.   

👉Si tiene alguna pregunta sobre el examen de detección de cáncer de seno, no dude en comunicarse con el Dr. Arrangoiz.

👉Rodrigo Arrangoiz MS, MD, FACS a surgical oncologist and is a member of Sociedad Quirúrgica S.C at the America British Cowdray Medical Center in Mexico City:

👉He is an expert in the management of breast cancer.

👉If you have any questions about the screening for breast cancer please fill free to contact Dr. Arrangoiz.