75 Comparing 21-Gene Assay Recurrence Scores Before and After Preoperative Radiation Boost in Patients Enrolled in a Phase 2 Prospective Clinical Trial

Publication
Article
Miami Breast Cancer Conference® Abstracts Supplement42nd Annual Miami Breast Cancer Conference® - Abstracts
Volume 39
Issue 4
Pages: 66

75 Comparing 21-Gene Assay Recurrence Scores Before and After Preoperative Radiation Boost in Patients Enrolled in a Phase 2 Prospective Clinical Trial

75 Comparing 21-Gene Assay Recurrence Scores Before and After Preoperative Radiation Boost in Patients Enrolled in a Phase 2 Prospective Clinical Trial

Background/Significance

Early-stage breast cancer is commonly treated with breast-conserving surgery (BCS) followed by whole breast irradiation (WBI). A radiation boost to the tumor bed is also recommended in some cases, is dependent on patient age and disease characteristics, and is usually delivered following BCS and WBI. We conducted a prospective, phase 2 clinical trial (NCT04871516) in which the radiation boost was delivered preoperatively instead of postoperatively, the first results of which have been previously published. Due to concerns that the preoperative radiation boost could possibly alter the genomic profile of the tumor, we compared the 21-gene assay results (Oncotype DX Breast Recurrence Score) before and after the boost, to see if a change may have altered systemic therapy.

Materials and Methods

Patients received a preoperative boost of 13.32 Gy in 4 daily fractions, followed by BCS 1 to 3 weeks after, followed by WBI of 36.63 Gy in 11 daily fractions 3 to 8 weeks after surgery. A total of 55 patients were enrolled in the trial. We randomly selected 17 patients to compare the 21-gene assay results before and after the boost. We used paired Student’s t-test to see whether the difference between the 2 sets of scores is statistically significant.

Results

Tissue was sufficient to run the assay on the core needle biopsy and the lumpectomy specimens in 15 patients. All patients had clinically negative axillary nodes. The median age at diagnosis was 68 years (range, 53-79). Average tumor size was 13.15 mm (range, 7-21). There were 3 lobular, 1 mucinous, and 11 ductal invasive carcinomas. All tumors were hormone receptor–positive and HER2-negative. The mean 21-gene assay result prior to the radiation boost was 12 (± SD, 7.92), and after was 13.47 (± SD 6.93). Paired Student’s t-test showed no significant difference between the pre- and postradiation results (t = 0.5399, P = .6). In 9 of 15 (60%) patients, the results of the 21-gene assay slightly increased after the boost by an average of 4.78 points (± SD, 2.05), and in 6 of 15 (40%), they slightly decreased by an average of 3.5 points (± SD, 2.74). In none of these 15 patients would the preoperative boost have altered systemic therapy.

Conclusion

In this cohort of patients from our preoperative radiation boost trial, results of the 21-gene assay were not significantly changed after the radiation boost. This indicates that, in this protocol, preoperative radiation boost would likely not alter systemic therapy decisions.

Articles in this issue

75 Comparing 21-Gene Assay Recurrence Scores Before and After Preoperative Radiation Boost in Patients Enrolled in a Phase 2 Prospective Clinical Trial
75 Comparing 21-Gene Assay Recurrence Scores Before and After Preoperative Radiation Boost in Patients Enrolled in a Phase 2 Prospective Clinical Trial
76 Electromagnetic Chip Bracketed vs Wire Bracketed Localization in Breast Conserving Surgery
76 Electromagnetic Chip Bracketed vs Wire Bracketed Localization in Breast Conserving Surgery
77 A Radio Opaque Suture May Improve Radiation Target Delineation in Post Lumpectomy Patients With Breast Cancer: A Retrospective Analysis
77 A Radio Opaque Suture May Improve Radiation Target Delineation in Post Lumpectomy Patients With Breast Cancer: A Retrospective Analysis
78 Comparison of Positive Margin Rate of Breast Cancer in Higher BMI Patients
78 Comparison of Positive Margin Rate of Breast Cancer in Higher BMI Patients
79 Case Series of Pathologic Upgrade After Reconstructive Breast Surgery
79 Case Series of Pathologic Upgrade After Reconstructive Breast Surgery
81 Assessing Recurrence Likelihood in Hormone Receptor–Positive/HER2-Negative Breast Cancer Patients Directly From MRI Using Imaging AI
81 Assessing Recurrence Likelihood in Hormone Receptor–Positive/HER2-Negative Breast Cancer Patients Directly From MRI Using Imaging AI
82 Efficacy, Safety, and Biomarker Analysis of ICARUS-BREAST01: A Phase 2 Study of Patritumab Deruxtecan (HER3-DXd) in Patients With HR+/HER2– Advanced Breast Cancer
82 Efficacy, Safety, and Biomarker Analysis of ICARUS-BREAST01: A Phase 2 Study of Patritumab Deruxtecan (HER3-DXd) in Patients With HR+/HER2– Advanced Breast Cancer
TPS 83 ELAINE 3: Open-Label, Randomized, Multicenter, Phase 3 Study of the Efficacy and Safety of Lasofoxifene Plus Abemaciclib for Treating Locally Advanced or Metastatic, ER+/HER2–, Breast Cancer With an ESR1 Mutation
TPS 83 ELAINE 3: Open-Label, Randomized, Multicenter, Phase 3 Study of the Efficacy and Safety of Lasofoxifene Plus Abemaciclib for Treating Locally Advanced or Metastatic, ER+/HER2–, Breast Cancer With an ESR1 Mutation
84 EQUALS: Vaginal/Sexual Health in Patients With Estrogen Receptor–Positive/HER2- Metastatic Breast Cancer
84 EQUALS: Vaginal/Sexual Health in Patients With Estrogen Receptor–Positive/HER2- Metastatic Breast Cancer
86 Elacestrant Combinations in Patients With Estrogen Receptor-Positive, HER2-Negative Locally Advanced or Metastatic Breast Cancer: Update From ELEVATE, a Phase 1b/2, Open-Label, Umbrella Study
86 Elacestrant Combinations in Patients With Estrogen Receptor-Positive, HER2-Negative Locally Advanced or Metastatic Breast Cancer: Update From ELEVATE, a Phase 1b/2, Open-Label, Umbrella Study
87 Elacestrant Plus Abemaciclib Combination in Patients With Estrogen Receptor-positive, HER2-Negative Advanced or Metastatic Breast Cancer
87 Elacestrant Plus Abemaciclib Combination in Patients With Estrogen Receptor-positive, HER2-Negative Advanced or Metastatic Breast Cancer
88 Eflapegrastim, a Long-Acting Granulocyte Colony–Stimulating Factor, Administered the Same Day as Chemotherapy in Patients With Early-Stage Breast Cancer: Results From a Multicenter, Open-Label Study
88 Eflapegrastim, a Long-Acting Granulocyte Colony–Stimulating Factor, Administered the Same Day as Chemotherapy in Patients With Early-Stage Breast Cancer: Results From a Multicenter, Open-Label Study
TPS 89 A Randomized Phase 3 Study of First-Line Saruparib (AZD5305) Plus Camizestrant Versus CDK4/6i Plus Physician’s Choice Endocrine Therapy or CDK4/6i Plus Camizestrant in Patients With HR+/HER2– Advanced Breast Cancer With BRCA1/BRCA2/PALB2 Mutations (EvoPAR-B)
TPS 89 A Randomized Phase 3 Study of First-Line Saruparib (AZD5305) Plus Camizestrant Versus CDK4/6i Plus Physician’s Choice Endocrine Therapy or CDK4/6i Plus Camizestrant in Patients With HR+/HER2– Advanced Breast Cancer With BRCA1/BRCA2/PALB2 Mutations (EvoPAR-B)
90 Contralateral Risk Reduction Mastectomy in Patients With Unilateral Breast Cancer: A Multinational and Multidisciplinary Survey—Physicians’ Perspective
90 Contralateral Risk Reduction Mastectomy in Patients With Unilateral Breast Cancer: A Multinational and Multidisciplinary Survey—Physicians’ Perspective
91 Adverse Effects and Financial Burden of Radiation Therapy in Patients With T3N0M0 Luminal Breast Cancer
91 Adverse Effects and Financial Burden of Radiation Therapy in Patients With T3N0M0 Luminal Breast Cancer

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