HORMONE REPLACEMENT THERAPY USE IN RELATION TO TUMOR BIOLOGY AND BREAST CANCER PROGNOSIS
[in Menopause - Hormones and CancerProceedings]
edited by M. Neves -e-Castro and B.G. Wren 2002 [MHC CH6 p49-53]

Outline and Commentary on the 2002 Proceedings
by Timothy D. Bilash MD, MS, OBGYN
June 2003

www.DrTimDelivers.com

Authors
H. Olsson [MHC CH 6]
Department of Oncology
University Hospital
Lund S-221 85
Sweden

1. Hypothesis: age and differentiation of the breast epithelium at the time of initiation reflects tumor biology at eventual diagnosis
   
   1. more immature breast tissue gives more advanced tumors
      
   2. supported by findings that less advanced tumor stage has been found to be more common in HRT users
      
      1. more highly differentiated
         
      2. lower proliferation rate
         
      3. low histological grade
         
      4. p53-negative status
         
      5. more frequent estrgoen receptor positive status
         
      6. may be more lobular type tumor rather than ductal
         
      7. current HRT users may show a higher S-phase percentage
         
         
2. Epidemiology
   
   1. highest risk for breast cancer seen for present use and low BMD
      
      1. [ANOTE] note that low BMD is associated with low serum estradiol
   3. Estrogen only seems to lower the risk
   4. continuous combined or sequential combined Estrogen effects are conflicting
      
      
3. Sweden study shows increased breast cancer risk of diagnosis with
   
   1. breast cancer had 1.74 risk ratio with HRT
      
   2. no overall increased risk of total malignant tumors
      
      1. other cancers had lowered risk each alone was not statistically significant
         
   3. HRT was significantly associated with a lower risk of dying, longer survival (Odds Ratio = 0.78)
      
   4. notes
      
      1. cox regression analysis similar to WHI
         
      2. newly incident tumors
         
      3. [ISLT] need mortality rates for that year
         
      4. need a combined "other tumor" group to compare for statistical significance
         
         
4. Research indicates that tumor biology and short-term prognosis are more favorable in breast cancer patients who have used HRT prior to diagnosis
   
   1. better survival for current HRT users
      
      1. breast cancer survival
         
      2. total survival
         
      3. this is irrespective of tumor stage, hormone receptor status, and tumor detection mode
         
   2. no survival benefit seen after 10 years from stopping for past HRT users
      
   3. family history and HRT exposure appear to be independent risk factors for breast cancer incidence
      
      
5. reduced sensitivity and specificity in breast cancer screening would be opposite to a screening bias
   
   1. screening bias- HRT group would screen more often and find more tumors
      
   2. sensitivity bias- HRT group would find fewer tumors when screened, due to increased density
      
   3. tumor size bias- HRT group would find more tumors when screened, due to tumors that are already there are bigger (estrogen is a growth hormone for breast tissue)
   4. these would influence incidence data
      
      
      

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