The Impact of Regional Nodal Radiation In Patients With Early-Stage Breast Cancer with Clinically Negative Nodes Treated with Breast-Conserving Therapy

Reviewer: John Wilson, MD
Abramson Cancer Center of the University of Pennsylvania
Last Modified: October 21, 2003

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Presenter: T. Vu
Presenter's Affiliation: CHUQ, Pavillon Hotel-Dieu de Quebec
Type of Session: Scientific

Background

  • Breast cancer is the most common cancer in women
  • Axillary dissection is often part of breast conservation therapy (BCT) because it can decrease axillary recurrence, it helps with staging and prognosis, it guides medical oncologists in choosing systemic therapy, and it helps radiation oncologists in designing radiation fields
  • There have been few studies on how to treat breast cancer patients with radiotherapy if they have not undergone an axillary dissection
  • One study performed in Milan by Zurrida et al (Annals of Surgical Oncology. 9(2):156-60, 2002 Mar) enrolled over 400 patients with tumors <1.2 cm and no axillary dissection and randomized them to BCT with or without axillary radiation. Only 2 patients in the no axillary radiation arm and only 1 patient in the axillary radiation arm developed axillary metastases at a median follow-up of 42 months.
  • This study was performed to evaluate the benefit of nodal irradiation in patients with larger tumors then the Milan trial

Materials and Methods

  • 673 women with T1-2, clinically node negative (cN0) invasive breast cancer were treated from 1972 to 1994 in Quebec
  • Patients underwent lumpectomy without axillary dissection followed by tangential breast irradiation
  • 285 women also received regional nodal radiation (R-XRT) of the axillary and supraclavicular nodes at the discretion of the treating radiation oncologist
  • Tangential radiation consisted of 50 Gy over 25 fractions or 45 Gy over 20 fractions, while R-XRT consisted of 40-44 Gy over 20-22 fractions
  • The median age was 63 years and 72% had T1 tumors
  • Median follow-up was 5 years

Results

  • 10% and 71% of patients received tamoxifen in the R-XRT and no R-XRT arm, respectively
  • 40% had T2 tumors in the R-XRT, compared with 19% in the no R-XRT arm
  • The nodal recurrence rate in all patients was 3% and 6% in the R-XRT and no R-XRT group, respectively (p=0.078)
  • Patients with T1 tumors had nodal recurrence rates of 1% in the R-XRT and 3% in the no R-XRT group, respectively (p=0.45)
  • Those with T2 tumors had recurrence rates of 3% in the R-XRT and 14% in the no R-XRT group, respectively (p=0.003)
  • Regional nodal recurrence was associated with local recurrence and T stage
  • Patients with T1 tumors receiving R-XRT had a hazard ratio for nodal recurrence of 0.88 (confidence interval 0.3-2.3, p=0.8), while those with T2 tumors receiving R-XRT had a hazard ration of 0.15 (confidence interval of 0.05-0.5, p=0.001)

Author's Conclusions

  • The use of axillary dissection is currently being debated, especially in older patients with smaller tumors
  • However, axillary failure rates may be as high as 18% without axillary treatment
  • This study shows that R-XRT of patients with clinically negative nodes who have not undergone axillary dissection does not affect nodal recurrence of T1 tumors, but significantly decreases the risk in T2 tumors
  • Regional nodal radiation should be strongly considered in patients with T2 tumors, especially those with adverse pathologic factors such as lymphovascular invasion, palpable tumor, and high grade pathology

Clinical/Scientific Implications

    This is a nonrandomized single-institutional study showing that regional nodal radiation provides a nodal control benefit in patients with T2 tumors and surgically unevaluated axillae. Patients with T1 tumors did not experience this benefit, which supports the findings of the randomized Milan study mentioned earlier. Because nodal radiation was administered at the discretion of the treating radiation oncologist, patients with poorer pathologic factors would be more likely to receive nodal radiation, which therefore gives more credence to this study. This study was performed largely before the availability of sentinel lymph node biopsy. Today, the toxicity of treating all patients with nodal radiation may outweigh the toxicity of treating all patients with a less involved sentinel node biopsy and then performing axillary dissection on those with positive sentinel nodes. But, for those patients who for some reason cannot or choose not to undergo sentinel node biopsy, regional nodal irradiation of patients with T2 or larger tumors should be considered, especially those with adverse pathologic factors.

Oncolink's ASTRO Coverage made possible by an unrestricted Educational Grant from Siemens Medical Solutions.


News
ASTRO: Short Course of Breast Cancer Irradiation Effective

Aug 22, 2014 - A three week course of radiation treatment may be as effective as six weeks or more in patients with early-stage breast cancer, according to research presented at the 51st Annual Meeting of the American Society for Radiation Oncology, held from Nov. 1 to 5 in Chicago. In a related study presented at the meeting, adding radiation to the internal mammary lymph nodes does not improve survival in patients with early-stage breast cancer.



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