Finasteride (MK-0906) and Male Breast Cancer - A Register-Based Nested Case-Control Study (MK-0906-162/2003.021).

Study Overview
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Brief Summary
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The objective of this study is to investigate the potential association between finasteride (MK-0906) exposure and the development of breast cancer in men residing in Denmark, Sweden, Finland, and Norway from data in national registries. The primary hypothesis of this study is that the previously reported increased incidence of male breast cancer among finasteride users is explained by confounding factors.

Official Title
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Finasteride and Male Breast Cancer - A Register-Based Nested Case-Control Study in Denmark, Finland, Norway, and Sweden

Conditions
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Male Breast Cancer

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Participant's study medical information available in population-based health and medical registries, prescription registries, and mortality registries in Denmark, Finland, Norway, or Sweden within the observation period of 1995 to 2013 Male with breast cancer with medical information in one of the 4 country-specific registries in this study OR country- and age-matched control men without breast cancer and with medical information in one of the 4 country-specific registries Study participant's exposure to finasteride is available Exclusion Criteria: For country- and age-matched control men without breast cancer Previous cancer diagnosis or treatment for cancer except non-melanoma skin cancer Previous prostatectomy Finasteride or dutasteride use (dutasteride is a drug in the same class as finasteride) within first 6 months of registration in the prescription registers (new user design).

Ages Eligible for Study
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Minimum Age: 35 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Male Finasteride Users<br>Male finasteride users aged 35 years and above in the registries of Denmark (1995-2013), Finland (1994-2013), Norway (2008-2013), and Sweden (2005-2013). | |
| Male Finasteride Non-users<br>Country-matched male finasteride non-users aged 35 years and above in the registries of Denmark (1995-2013), Finland (1994-2013), Norway (2008-2013), and Sweden (2005-2013). | |
| Men with Breast Cancer<br>Breast cancer cases among men aged 35 years and above in the registries of Denmark (1995-2013), Finland (1994-2013), Norway (2008-2013), and Sweden (2005-2013). | |
| Men without Breast Cancer<br>Country- and age-matched controls: men without breast cancer aged 35 years and above in the registries of Denmark (1995-2013), Finland (1994-2013), Norway (2008-2013), and Sweden (2005-2013). | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Stage 1 - Person-Years of Exposure to Finasteride by Participant Age and Year |  | Up to 14 years | 
| Stage 1 - Initial Incidence Rates of Male Breast Cancer Stratified by Exposure to Finasteride |  | Up to 14 years | 
| Stage 1 - All-Cause Mortality Rates in Males with Breast Cancer by Exposure to Finasteride |  | Up to 14 years | 
| Stage 2 - Odds (or Likelihood) of Exposure to Finasteride in Male Breast Cancer Cases Relative to Controls |  | Up to 19 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Males breast cancer, Finasteride, PROSCAR®, PROPECIA®