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Letrozole in Treating Postmenopausal Women With Ductal Carcinoma in Situ

Primary Purpose

Breast Cancer

Status
Completed
Phase
Phase 2
Locations
United States
Study Type
Interventional
Intervention
letrozole
MRI
conventional surgery
Sponsored by
Alliance for Clinical Trials in Oncology
About
Eligibility
Locations
Arms
Outcomes
Full info

About this trial

This is an interventional treatment trial for Breast Cancer focused on measuring ductal breast carcinoma in situ, estrogen receptor-positive breast cancer

Eligibility Criteria

18 Years - undefined (Adult, Older Adult)FemaleDoes not accept healthy volunteers

Eligibility Criteria:

  1. Histologic documentation: Pathologic confirmation of ductal carcinoma in situ (DCIS) of the female breast without invasive cancer, with diagnosis rendered on core biopsy only, completed within 60 days before registration. Patients diagnosed with DCIS on the basis of surgical biopsy are not eligible for this study.

    1. Patients with microinvasion on diagnostic core biopsy, defined as tumor ≤ 1 mm in greatest dimension, will be allowed to participate.
    2. All patients must have a clip placed, either at the time of the diagnostic biopsy or at the time of the baseline MRI prior to the start of treatment.
  2. Tissue samples: Patient has diagnostic tissue available for correlative studies.
  3. Clinical stage: Tis or T1mi N0, M0
  4. Hormone receptor status: DCIS must express estrogen and/or progesterone receptor, as determined by immunohistochemical methods on the diagnostic pathology sample, according to the local institution's standard protocol. Greater than or equal to 1% cells will be considered to be positive.
  5. Menopausal status: Patients must be postmenopausal defined as:

    1. Age ≥ 55 years and one year or more of amenorrhea
    2. Age < 55 years and one year or more amenorrhea, with an estradiol assay < 20pg/ml
    3. Surgical menopause with bilateral oophorectomy (at least 28 days must elapse from surgery to time of study registration)

    The use of GnRH analogs to achieve post menopausal status is not allowed.

  6. Prior treatment:

    1. No prior surgical excision in the index breast for current DCIS diagnosis of DCIS
    2. Any exogenous hormone therapy must be completed 4 weeks prior to registration
    3. Any patients with a history of tamoxifen or raloxifene use within two years of current DCIS diagnosis are not eligible
    4. No prior neoadjuvant/adjuvant therapy for current DCIS diagnosis
  7. Contraindication to MRI: No contraindications to breast MRI
  8. Measurable disease: Mammographic extent of calcifications must be accurately measurable in at least one dimension with each lesion ≥ 1 cm and ≤ 7 cm

    1. DCIS must be visible on MRI based on central review.
    2. Patients with palpable DCIS or adenopathy are not eligible to participate.
    3. Patients with multifocal or bilateral disease are eligible.
  9. History of osteoporosis: Women diagnosed with osteoporosis may participate in this trial provided they are receiving appropriate therapy or if they have declined therapy.
  10. Age: Patients ≥ 18 years of age
  11. Performance Status: ECOG performance status 0 or 1
  12. Pregnancy/nursing status: Not pregnant or nursing
  13. Required Initial Laboratory Values:

    1. ANC ≥ 1,000/μL
    2. Platelet count ≥ 100,000/μL
    3. Serum creatinine ≤ 1.7 mg/dL
    4. Bilirubin ≤ 2.0 mg/dL
    5. AST/ALT ≤ 2.5 times upper limit of normal
    6. Serum estradiol level assay < 20 pg/mL *Required for patients < 55 years of age and one year or more of amenorrhea

Sites / Locations

  • Cedars Sinai Medical Center
  • Bay Area Tumor Institute
  • UCSF Medical Center-Mount Zion
  • Exempla Saint Joseph Hospital
  • Delaware Clinical and Laboratory Physicians PA
  • Helen F Graham Cancer Center
  • Medical Oncology Hematology Consultants PA
  • Regional Hematology and Oncology PA
  • Christiana Care Health System-Christiana Hospital
  • University of Iowa/Holden Comprehensive Cancer Center
  • Saint Elizabeth Medical Center South
  • Saint Elizabeth Fort Thomas
  • Baptist Health Lexington
  • Northwest Hospital Center
  • Dana Farber Cancer Institute
  • Sparrow Hospital
  • Mayo Clinic Cancer Center
  • Saint Luke's Hospital of Kansas City
  • Missouri Baptist Medical Center
  • University of North Carolina at Chapel Hill
  • Duke University Medical Center
  • Margaret R Pardee Memorial Hospital
  • Ohio State University Comprehensive Cancer Center
  • Riverside Methodist Hospital
  • Grant Medical Center
  • Southern Ohio Medical Center
  • University of Oklahoma Health Sciences Center
  • Medical University of South Carolina
  • M. D. Anderson Cancer Center
  • Sentara Cancer Institute at Sentara CarePlex Hospital
  • Sentara Leigh Hospital
  • Sentara Hospitals

Arms of the Study

Arm 1

Arm Type

Experimental

Arm Label

letrozole + MRI + surgery

Arm Description

Patients receive letrozole (2.5 mg) one tablet each day after confirmation that the MRI is acceptable. There is a 3 and 6 month disease evaluation by MRI of both breasts. If the DCIS has grown, the patient will have surgery to remove it and will continue to take letrozole until the day before surgery. It is expected that decisions regarding any adjuvant treatment will be made individually based on best practice guidelines, using informed and shared decision making between the patient and provider.

Outcomes

Primary Outcome Measures

Mean Total MRI Functional Tumor Volume (FTV) Change From Baseline to Month 3 (V3)
Mean total MRI FTV change from baseline to month 3 (V3): For patients with more than one measureable lesion on the MRI, the sum over all measureable lesions on the MRI was calculated at each time point. V3 was calculated by subtracting the total MRI FTV measured (i.e. the sum over all lesions present with MRI FTV measurements) at 3 months from the total MRI FTV measured at baseline. For V3 the raw change in the volume will be calculated for each patient and a mean and 95% confidence interval will be constructed using two-sided t-tests.
Mean Total MRI Functional Tumor Volume (FTV) Change From Baseline to Month 6 (V6)
Mean total MRI FTV change from baseline to month 6 (V6): For patients with more than one measureable lesion on the MRI, the sum over all measureable lesions on the MRI was calculated at each time point. V6 was calculated by subtracting the total MRI FTV measured at 6 months from the total MRI FTV measured at baseline. For V6 the raw change in the volume will be calculated for each patient and a mean and 95% confidence interval will be constructed using two-sided t-tests.

Secondary Outcome Measures

Mean Total MRI Tumor Diameter Change From Baseline to Month 3
To ascertain the change in maximum tumor diameter from baseline to 3 months (D3) the same methods as in Primary outcome #1 will be used but on diameter instead of volume. For patients with more than one lesion longest diameter measurement, the sum of all lesion longest diameter measurements was calculated.
Change in Maximum Diameter at 6-months Based on Mammographic Measurement (MD6)
Change in maximum diameter at 6-months based on mammographic measurement (MD6) will be estimated using the methods in Primary Outcome #1, but using the mammographic measurements instead.
Type of Primary Surgery (Mastectomy or Lumpectomy)
Rate of Mastectomy will be estimated as the number of mastectomies divided by the number of surgeries. A 95% confidence interval will be constructed using exact binomial methods. Rate of Lumpectomy will be estimated as the number of lumpectomies divided by the number of surgeries. A 95% confidence interval will be constructed using exact binomial methods.
Number of Re-excisions Required to Obtain Clear Margins
Extent of Residual DCIS Post Surgery
Presence of Invasive Cancer at Surgery
Size of Margins (Smallest) at Surgery
Incidence of Toxicity as Assessed by the National Cancer Institute Common Terminology Criteria for Adverse Events Version 4.0
The maximum grade for each type of adverse event will be recorded for each patient, and frequency tables will be reviewed to determine patterns. Additionally, the relationship of the adverse event(s) to the study treatment will be taken into consideration. The percentage of patients with a maximum grade 3 or higher adverse event at least possibly related to the study treatment are reported below.
Mean Total MRI Tumor Diameter Change From Baseline to Month 6
Mean total MRI tumor diameter change from baseline to month 6: To ascertain the change in maximum tumor diameter from baseline to 6 months (D6) the same methods as in Primary Outcome #2 will be used but on diameter instead of volume.
Mean Total MRI Tumor Diameter Change From Baseline to Month 6
To ascertain the change in maximum tumor diameter from baseline to 6 months (D6) the same methods as in Primary outcome #2 will be used but on diameter instead of volume. For patients with more than one lesion longest diameter measurement, the sum of all lesion longest diameter measurements was calculated.

Full Information

First Posted
September 21, 2011
Last Updated
February 26, 2018
Sponsor
Alliance for Clinical Trials in Oncology
Collaborators
National Cancer Institute (NCI)
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1. Study Identification

Unique Protocol Identification Number
NCT01439711
Brief Title
Letrozole in Treating Postmenopausal Women With Ductal Carcinoma in Situ
Official Title
Phase II Study of Neoadjuvant Letrozole for Postmenopausal Women With Estrogen Receptor Positive Ductal Carcinoma In SITU (DCIS)
Study Type
Interventional

2. Study Status

Record Verification Date
February 2018
Overall Recruitment Status
Completed
Study Start Date
February 2012 (Actual)
Primary Completion Date
August 2016 (Actual)
Study Completion Date
January 2018 (Actual)

3. Sponsor/Collaborators

Responsible Party, by Official Title
Sponsor
Name of the Sponsor
Alliance for Clinical Trials in Oncology
Collaborators
National Cancer Institute (NCI)

4. Oversight

Data Monitoring Committee
Yes

5. Study Description

Brief Summary
RATIONALE: Estrogen can cause the growth of breast cancer cells. Hormone therapy using letrozole may fight breast cancer by blocking the use of estrogen by the tumor cells or by lowering the amount of estrogen the body makes. PURPOSE: This phase II trial is studying how well letrozole works in treating women with ductal carcinoma in situ.
Detailed Description
Treatment with letrozole begins within 21 days of registration, and only after notification has been received from the UCSF Breast MRI Research Laboratory that the baseline MRI is acceptable. Protocol therapy will consist of 6 months of letrozole, administered orally at a dose of 2.5 mg/day. Patients will have a MRI for disease evaluation at months 3 and 6. All patients will continue to take study drug until the day prior to surgery, whether at month 3 or at month 6 or may stop if they experience unacceptable toxicity. It is expected that decisions regarding any adjuvant treatment (eg, radiation and hormonal therapy) will be made individually based on the best practice guidelines, using informed and shared decision making between patient and provider. The primary and secondary objectives are provided below. Primary objective: 1. To estimate the mean change in MRI tumor volume from pretreatment to completion of preoperative endocrine therapy in estrogen receptor-positive (ER+) ductal carcinoma in situ (DCIS), as well as to determine whether 3-month change in volume correlates with 6-month change. Secondary objectives: To assess radiographic-pathologic correlation between MRI findings and histopathology, including the prevalence of occult invasive cancer in patients undergoing neoadjuvant endocrine therapy for DCIS. To compare changes in MRI maximum lesion diameter and mammographic extent at baseline and following treatment. These are two additional radiographic parameters which may also biological response to therapy. To determine practice patterns of adjuvant hormonal and radiation therapy in patients who complete neoadjuvant letrozole therapy for DCIS. To determine whether Ki67 is reduced with neoadjuvant letrozole treatment for DCIS, and to compare the reduction in proliferation between radiographic responders and non-responders. To identify baseline IHC and expression biomarkers predictive of response to treatment, with response determined by extent of Ki67 reduction. Subsets showing the greatest reduction in Ki67 would be the most likely candidates for non-operative treatment in future studies. To examine whether germline polymorphisms are associated with clinical endpoints, including treatment-related toxicity or efficacy outcomes, or with expression of biomarkers in serum or tumor. To assess quality-of-life and musculoskeletal symptoms associated with neoadjuvant letrozole for ER positive DCIS. Patients will be followed up to 6 months post-surgery.

6. Conditions and Keywords

Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Breast Cancer
Keywords
ductal breast carcinoma in situ, estrogen receptor-positive breast cancer

7. Study Design

Primary Purpose
Treatment
Study Phase
Phase 2
Interventional Study Model
Single Group Assignment
Masking
None (Open Label)
Allocation
N/A
Enrollment
108 (Actual)

8. Arms, Groups, and Interventions

Arm Title
letrozole + MRI + surgery
Arm Type
Experimental
Arm Description
Patients receive letrozole (2.5 mg) one tablet each day after confirmation that the MRI is acceptable. There is a 3 and 6 month disease evaluation by MRI of both breasts. If the DCIS has grown, the patient will have surgery to remove it and will continue to take letrozole until the day before surgery. It is expected that decisions regarding any adjuvant treatment will be made individually based on best practice guidelines, using informed and shared decision making between the patient and provider.
Intervention Type
Drug
Intervention Name(s)
letrozole
Intervention Type
Procedure
Intervention Name(s)
MRI
Intervention Type
Procedure
Intervention Name(s)
conventional surgery
Primary Outcome Measure Information:
Title
Mean Total MRI Functional Tumor Volume (FTV) Change From Baseline to Month 3 (V3)
Description
Mean total MRI FTV change from baseline to month 3 (V3): For patients with more than one measureable lesion on the MRI, the sum over all measureable lesions on the MRI was calculated at each time point. V3 was calculated by subtracting the total MRI FTV measured (i.e. the sum over all lesions present with MRI FTV measurements) at 3 months from the total MRI FTV measured at baseline. For V3 the raw change in the volume will be calculated for each patient and a mean and 95% confidence interval will be constructed using two-sided t-tests.
Time Frame
up to 3 months from start of treatment
Title
Mean Total MRI Functional Tumor Volume (FTV) Change From Baseline to Month 6 (V6)
Description
Mean total MRI FTV change from baseline to month 6 (V6): For patients with more than one measureable lesion on the MRI, the sum over all measureable lesions on the MRI was calculated at each time point. V6 was calculated by subtracting the total MRI FTV measured at 6 months from the total MRI FTV measured at baseline. For V6 the raw change in the volume will be calculated for each patient and a mean and 95% confidence interval will be constructed using two-sided t-tests.
Time Frame
up to 6 months from start of treatment
Secondary Outcome Measure Information:
Title
Mean Total MRI Tumor Diameter Change From Baseline to Month 3
Description
To ascertain the change in maximum tumor diameter from baseline to 3 months (D3) the same methods as in Primary outcome #1 will be used but on diameter instead of volume. For patients with more than one lesion longest diameter measurement, the sum of all lesion longest diameter measurements was calculated.
Time Frame
3-months
Title
Change in Maximum Diameter at 6-months Based on Mammographic Measurement (MD6)
Description
Change in maximum diameter at 6-months based on mammographic measurement (MD6) will be estimated using the methods in Primary Outcome #1, but using the mammographic measurements instead.
Time Frame
6-months
Title
Type of Primary Surgery (Mastectomy or Lumpectomy)
Description
Rate of Mastectomy will be estimated as the number of mastectomies divided by the number of surgeries. A 95% confidence interval will be constructed using exact binomial methods. Rate of Lumpectomy will be estimated as the number of lumpectomies divided by the number of surgeries. A 95% confidence interval will be constructed using exact binomial methods.
Time Frame
up to 6 months
Title
Number of Re-excisions Required to Obtain Clear Margins
Time Frame
3-months and 6-months
Title
Extent of Residual DCIS Post Surgery
Time Frame
Up to 6 months post-surgery
Title
Presence of Invasive Cancer at Surgery
Time Frame
3-months and 6-months
Title
Size of Margins (Smallest) at Surgery
Time Frame
3-months and 6-months
Title
Incidence of Toxicity as Assessed by the National Cancer Institute Common Terminology Criteria for Adverse Events Version 4.0
Description
The maximum grade for each type of adverse event will be recorded for each patient, and frequency tables will be reviewed to determine patterns. Additionally, the relationship of the adverse event(s) to the study treatment will be taken into consideration. The percentage of patients with a maximum grade 3 or higher adverse event at least possibly related to the study treatment are reported below.
Time Frame
Up to 6 months post surgery
Title
Mean Total MRI Tumor Diameter Change From Baseline to Month 6
Description
Mean total MRI tumor diameter change from baseline to month 6: To ascertain the change in maximum tumor diameter from baseline to 6 months (D6) the same methods as in Primary Outcome #2 will be used but on diameter instead of volume.
Time Frame
6 months
Title
Mean Total MRI Tumor Diameter Change From Baseline to Month 6
Description
To ascertain the change in maximum tumor diameter from baseline to 6 months (D6) the same methods as in Primary outcome #2 will be used but on diameter instead of volume. For patients with more than one lesion longest diameter measurement, the sum of all lesion longest diameter measurements was calculated.
Time Frame
6 months

10. Eligibility

Sex
Female
Minimum Age & Unit of Time
18 Years
Accepts Healthy Volunteers
No
Eligibility Criteria
Eligibility Criteria: Histologic documentation: Pathologic confirmation of ductal carcinoma in situ (DCIS) of the female breast without invasive cancer, with diagnosis rendered on core biopsy only, completed within 60 days before registration. Patients diagnosed with DCIS on the basis of surgical biopsy are not eligible for this study. Patients with microinvasion on diagnostic core biopsy, defined as tumor ≤ 1 mm in greatest dimension, will be allowed to participate. All patients must have a clip placed, either at the time of the diagnostic biopsy or at the time of the baseline MRI prior to the start of treatment. Tissue samples: Patient has diagnostic tissue available for correlative studies. Clinical stage: Tis or T1mi N0, M0 Hormone receptor status: DCIS must express estrogen and/or progesterone receptor, as determined by immunohistochemical methods on the diagnostic pathology sample, according to the local institution's standard protocol. Greater than or equal to 1% cells will be considered to be positive. Menopausal status: Patients must be postmenopausal defined as: Age ≥ 55 years and one year or more of amenorrhea Age < 55 years and one year or more amenorrhea, with an estradiol assay < 20pg/ml Surgical menopause with bilateral oophorectomy (at least 28 days must elapse from surgery to time of study registration) The use of GnRH analogs to achieve post menopausal status is not allowed. Prior treatment: No prior surgical excision in the index breast for current DCIS diagnosis of DCIS Any exogenous hormone therapy must be completed 4 weeks prior to registration Any patients with a history of tamoxifen or raloxifene use within two years of current DCIS diagnosis are not eligible No prior neoadjuvant/adjuvant therapy for current DCIS diagnosis Contraindication to MRI: No contraindications to breast MRI Measurable disease: Mammographic extent of calcifications must be accurately measurable in at least one dimension with each lesion ≥ 1 cm and ≤ 7 cm DCIS must be visible on MRI based on central review. Patients with palpable DCIS or adenopathy are not eligible to participate. Patients with multifocal or bilateral disease are eligible. History of osteoporosis: Women diagnosed with osteoporosis may participate in this trial provided they are receiving appropriate therapy or if they have declined therapy. Age: Patients ≥ 18 years of age Performance Status: ECOG performance status 0 or 1 Pregnancy/nursing status: Not pregnant or nursing Required Initial Laboratory Values: ANC ≥ 1,000/μL Platelet count ≥ 100,000/μL Serum creatinine ≤ 1.7 mg/dL Bilirubin ≤ 2.0 mg/dL AST/ALT ≤ 2.5 times upper limit of normal Serum estradiol level assay < 20 pg/mL *Required for patients < 55 years of age and one year or more of amenorrhea
Overall Study Officials:
First Name & Middle Initial & Last Name & Degree
Shelley Hwang, MD, MPH
Organizational Affiliation
Duke University
Official's Role
Study Chair
Facility Information:
Facility Name
Cedars Sinai Medical Center
City
Los Angeles
State/Province
California
ZIP/Postal Code
90048
Country
United States
Facility Name
Bay Area Tumor Institute
City
Oakland
State/Province
California
ZIP/Postal Code
94609
Country
United States
Facility Name
UCSF Medical Center-Mount Zion
City
San Francisco
State/Province
California
ZIP/Postal Code
94115
Country
United States
Facility Name
Exempla Saint Joseph Hospital
City
Denver
State/Province
Colorado
ZIP/Postal Code
80218
Country
United States
Facility Name
Delaware Clinical and Laboratory Physicians PA
City
Newark
State/Province
Delaware
ZIP/Postal Code
19713
Country
United States
Facility Name
Helen F Graham Cancer Center
City
Newark
State/Province
Delaware
ZIP/Postal Code
19713
Country
United States
Facility Name
Medical Oncology Hematology Consultants PA
City
Newark
State/Province
Delaware
ZIP/Postal Code
19713
Country
United States
Facility Name
Regional Hematology and Oncology PA
City
Newark
State/Province
Delaware
ZIP/Postal Code
19713
Country
United States
Facility Name
Christiana Care Health System-Christiana Hospital
City
Newark
State/Province
Delaware
ZIP/Postal Code
19718
Country
United States
Facility Name
University of Iowa/Holden Comprehensive Cancer Center
City
Iowa City
State/Province
Iowa
ZIP/Postal Code
52242
Country
United States
Facility Name
Saint Elizabeth Medical Center South
City
Edgewood
State/Province
Kentucky
ZIP/Postal Code
41017
Country
United States
Facility Name
Saint Elizabeth Fort Thomas
City
Fort Thomas
State/Province
Kentucky
ZIP/Postal Code
41075
Country
United States
Facility Name
Baptist Health Lexington
City
Lexington
State/Province
Kentucky
ZIP/Postal Code
40503
Country
United States
Facility Name
Northwest Hospital Center
City
Randallstown
State/Province
Maryland
ZIP/Postal Code
21133
Country
United States
Facility Name
Dana Farber Cancer Institute
City
Boston
State/Province
Massachusetts
ZIP/Postal Code
02115
Country
United States
Facility Name
Sparrow Hospital
City
Lansing
State/Province
Michigan
ZIP/Postal Code
48912
Country
United States
Facility Name
Mayo Clinic Cancer Center
City
Rochester
State/Province
Minnesota
ZIP/Postal Code
55905
Country
United States
Facility Name
Saint Luke's Hospital of Kansas City
City
Kansas City
State/Province
Missouri
ZIP/Postal Code
64111
Country
United States
Facility Name
Missouri Baptist Medical Center
City
Saint Louis
State/Province
Missouri
ZIP/Postal Code
63131
Country
United States
Facility Name
University of North Carolina at Chapel Hill
City
Chapel Hill
State/Province
North Carolina
ZIP/Postal Code
27599
Country
United States
Facility Name
Duke University Medical Center
City
Durham
State/Province
North Carolina
ZIP/Postal Code
27710
Country
United States
Facility Name
Margaret R Pardee Memorial Hospital
City
Hendersonville
State/Province
North Carolina
ZIP/Postal Code
28791
Country
United States
Facility Name
Ohio State University Comprehensive Cancer Center
City
Columbus
State/Province
Ohio
ZIP/Postal Code
43210
Country
United States
Facility Name
Riverside Methodist Hospital
City
Columbus
State/Province
Ohio
ZIP/Postal Code
43214
Country
United States
Facility Name
Grant Medical Center
City
Columbus
State/Province
Ohio
ZIP/Postal Code
43215
Country
United States
Facility Name
Southern Ohio Medical Center
City
Portsmouth
State/Province
Ohio
ZIP/Postal Code
45662
Country
United States
Facility Name
University of Oklahoma Health Sciences Center
City
Oklahoma City
State/Province
Oklahoma
ZIP/Postal Code
73104
Country
United States
Facility Name
Medical University of South Carolina
City
Charleston
State/Province
South Carolina
ZIP/Postal Code
29425
Country
United States
Facility Name
M. D. Anderson Cancer Center
City
Houston
State/Province
Texas
ZIP/Postal Code
77030
Country
United States
Facility Name
Sentara Cancer Institute at Sentara CarePlex Hospital
City
Hampton
State/Province
Virginia
ZIP/Postal Code
23666
Country
United States
Facility Name
Sentara Leigh Hospital
City
Norfolk
State/Province
Virginia
ZIP/Postal Code
23502
Country
United States
Facility Name
Sentara Hospitals
City
Norfolk
State/Province
Virginia
ZIP/Postal Code
23507
Country
United States

12. IPD Sharing Statement

Citations:
PubMed Identifier
32125937
Citation
Hwang ES, Hyslop T, Hendrix LH, Duong S, Bedrosian I, Price E, Caudle A, Hieken T, Guenther J, Hudis CA, Winer E, Lyss AP, Dickson-Witmer D, Hoefer R, Ollila DW, Hardman T, Marks J, Chen YY, Krings G, Esserman L, Hylton N. Phase II Single-Arm Study of Preoperative Letrozole for Estrogen Receptor-Positive Postmenopausal Ductal Carcinoma In Situ: CALGB 40903 (Alliance). J Clin Oncol. 2020 Apr 20;38(12):1284-1292. doi: 10.1200/JCO.19.00510. Epub 2020 Mar 3.
Results Reference
derived

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Letrozole in Treating Postmenopausal Women With Ductal Carcinoma in Situ

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