Prognostic and Predictive Factors for Small Breast Tumors

Study Overview
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Brief Summary
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Because of mammography screening increasingly more women are diagnosed with centimeter or subcentimeter node-negative breast cancer (i.e., T1abN0); these tumors account for approximately 19% of all newly diagnosed breast cancers in Sweden. Although the long term relapse-free survival rates among patients with such tumors is as high as ≥90%, some reports suggest that certain patient subgroups may have rates <75%. Firmly established prognostic and predictive factors for patients with T1abN0 tumors are, however, lacking. This is a nationwide, register-based cohort study investigating prognostic and predictive factors in women with centimeter or subcentimeter breast cancer. The study hypotheses are: 1) Established prognostic and/or predictive factors in overall breast cancer are prognostic and/or predictive factors also in centimeter or subcentimeter node-negative breast cancer; 2) The established relative reduction in risk of recurrence and death of adjuvant treatment for overall breast cancer are similar in centimeter or subcentimeter node-negative breast cancer.

Official Title
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Prognosis, Prognostic Factors and Predictive Factors in Centimeter or Subcentimeter Node-negative Breast Cancer

Conditions
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Breast Cancer

Intervention / Treatment
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* Drug: Endocrine therapy
* Radiation: Radiotherapy
* Drug: Herceptin
* Drug: Chemotherapy
* Procedure: Type of breast cancer surgery
* Other: Age at diagnosis
* Other: Screen detected tumor
* Other: Menopausal status at diagnosis
* Other: Tumor size
* Other: Estrogen receptor (ER) status
* Other: Tumor grade
* Other: HER2-status
* Other: Intrinsic subgroups of breast cancer
* Other: Nodal status


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Female. Operated for centimeter or subcentimeter breast cancer. Exclusion Criteria: Previous breast cancer. Metastatic breast cancer at diagnosis.

Ages Eligible for Study
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Maximum Age: 100 Years

Sexes Eligible for Study
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Female

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Women with T1ab breast cancer.<br> | Drug: Endocrine therapy<br>* Endocrine treatment versus no endocrine therapy (in women with hormone receptor positive1 disease).<br>Radiation: Radiotherapy<br>* Radiotherapy versus no radiotherapy.<br>Drug: Herceptin<br>* Trastuzumab versus no trastuzumab (in women with HER2-positive disease).<br>Drug: Chemotherapy<br>* Chemotherapy versus no chemotherapy.<br>Procedure: Type of breast cancer surgery<br>* Type of surgery (partial mastectomy, mastectomy, other).<br>Other: Age at diagnosis<br>* Age at diagnosis (<35, 35-<50, 50-<70, ≥70).<br>Other: Screen detected tumor<br>* Screening detected tumor (yes, no).<br>Other: Menopausal status at diagnosis<br>* Menopausal status (premenopausal, postmenopausal).<br>Other: Tumor size<br>* Tumor size (≤5 mm, 6-≤10 mm).<br>Other: Estrogen receptor (ER) status<br>* ER-status (positive, negative).<br>Other: Tumor grade<br>* Tumor grade (1, 2, 3).<br>Other: HER2-status<br>* HER2-status (positive, negative).<br>Other: Intrinsic subgroups of breast cancer<br>* Intrinsic subgroup proxy (Luminal A, Luminal B (HER2-negative), Luminal B (HER2-positive), HER2-positive (non-luminal), Triple negative).<br>Other: Nodal status<br>* N-status (N0, N1).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Breast cancer specific death |  | January 1, 1977 to December 31, 2014 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Death from any cause |  | January 1, 1977 to July 30, 2016 | 
| Metachronous breast cancer | Ipsilateral or contralateral breast cancer | January 1, 1977 to July 30, 2016 |