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- Tari King, MD
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- Tiffany A. Traina, MD
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- Conleth Murphy, MD
Post by: Tari King, MD; Tiffany A. Traina, MD; Conleth Murphy, MD
Post from: ASCO Breast Cancer Symposium
With regards to local-regional therapy Chen et al. reported their single institution results comparing the efficacy of three forms of accelerated partial breast irradiation (APBI) at William Beaumont Hosptial (abst # 210). In their group of 373 patients selected for APBI based on age, histology, margin and lymph node status the 5-yr actuarial local recurrence rate was 1.7% with no difference between the 3 APBI modalities [1.6% interstitial HDR/LDR, 1.1% 3-D conformal external beam, 2.6% Mammosite]. The median follow up was 6.4 years with longer follow up among interstitial HDR/LDR patients (9.7yrs) as compared to the other two treatment modalities, 4.2yrs for 3-D CRT and 4.1 yrs for MS respectively. Continued follow-up among these groups, particularly for 3-D CRT and MS, will be needed to assess the long term equivalency of these 3 APBI modalities. In a nice review of the topic, Dr. Moran a Radiation Oncologist from Yale University highlighted the importance of adhering to the ASTRO guidelines when considering APBI in clinical practice.
Data supporting the importance of tumor intrinsic subtype in local regional therapy outcomes continues to emerge. Dominici et al (abstract #74) demonstrated that tumor subtype as measured by the IHC surrogates (ER,PR,Her2) was a prognostic factor for LRR after mastectomy with our without PMRT. In the absence of PMRT, nodal burden, luminal B (HR 4.26, CI 1.05-17.33, p =0.04) and basal phenotype (HR 13.87, CI 4.96-38.8, p=0.015) predicted for worse LRR-free survival whereas in the presence of PMRT, only basal subtype (HR 9.47, CI 1.85-48.36, p= 0.007) was associated with significantly worse LRR-free survival on MVA. Dr. Marc van de Vijver from the Netherlands group also reviewed their efforts to identify molecular markers predicting for local control. Finally, with respect to PFS and OS, Ellis et al (abstract #33) presented data suggesting that the PAM50 qRT-PCR gene expression classifier is highly prognostic among patients with estrogen receptor positive disease treated with tamoxifen and was superior to IHC classifiers and he Adjuvant! Online tool in this group.
