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Eighteen-Year Results in the Treatment of Early-Stage Breast Cancer With Breast Conservation Versus Mastectomy
Reviewer: Roberto Santiago, MD
Last Modified: October 8, 2002
Presenter: Matthew Poggi
Presenter's Affiliation: Radiation Oncology Branch, NCI, Bethesda, MD
Type of Session: Scientific
Several randomized clinical trials comparing conservative surgery followed by whole breast irradiation to mastectomy for patients with early stage breast cancer have reported long-term outcomes. These studies include the Milan trial report with 16 years of median follow-up (MFU), the Institute Gustave Roussy trial report with 14.5 years MFU, and the EORTC trial report with 13.4 years MFU. Still, there is little data with follow-up greater than 15 years on the outcomes of breast conservation versus mastectomy for early stage breast cancer. This study updates the results of the randomized trial performed by the US NCI with over 18 years of MFU.
Materials and Methods
- Two hundred forty seven patients with clinical stage I and II breast cancer were enrolled on an institutionally reviewed protocol and randomly assigned to undergo either modified radical mastectomy (116) or lumpectomy (121), axillary dissection (levels I-III) and radiation therapy (RT).
- The 237 patients who underwent randomization (10 patients refused randomization) have been followed for a median potential follow-up of 18.4 years. Two were lost to follow-up, both in the conservation arm.
- Pathology was centrally reviewed. Gross total excision during lumpectomy was required and re-excision to this end was permitted. A microscopic negative margin status was not mandatory.
- RT consisted of 45-50.4 Gy to the whole breast followed by a 15-20 Gy boost to the tumor bed (most commonly with Ir implant). If the primary was in the medial or the axilla was involved, the IMN and supraclavicular fossa were irradiated. If there was ECE of axillary nodes the axilla was also irradiated.
- All node positive patients received chemotherapy and, after 1985, many also received Tamoxifen.
- No post-mastectomy chest wall irradiation was delivered.
- The primary end points were overall survival and disease-free survival.
- At 18.4 years, the overall survival was 58 percent for patients assigned to mastectomy and 54 percent for patients assigned to lumpectomy plus radiation. There was no statistically significant difference in survival between the two groups (p=0.67).
- Disease-free survival at 18 years was 67 percent for the patients assigned to mastectomy and 63 percent for those assigned to lumpectomy plus radiation (p=0.64) after recurrences successfully salvaged by mastectomy were censored from analysis.
- 27 of 121 women treated with breast conservation experienced an ipsilateral in-breast cancer event.
- There was no statistically significant difference in distant disease-free survival which was 69 percent for mastectomy and 68 percent for breast conservation (p=0.82).
- In patients with positive lymph nodes, the overall and disease-free survival was not statistically different between the arms, although there was a trend favoring breast conservation.
- Breast conservation with lumpectomy and radiation offers equivalent overall and disease-free survival to mastectomy almost into the third decade after treatment.
- Ipsilateral in-breast cancer events were observed throughout the entire follow-up period for the breast conservation group. An analysis of these events will be reported in the near future.
- These results confirm the long term equivalence of this two modalities in early breast cancer.
- These results should not be used to measure the effectiveness of partial breast irradiation techniques as the patient cohorts are different (PBI candidates have much better prognostic factors and patient screening and treatment have refine since the 1980's).
- Long-term BCT data clearly shows that despite whole breast irradiation ipsilateral in-breast cancer events continue to occur stressing the need for long-term evaluation of new PBI approaches.
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