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Table 2 Hot flash frequency and severity and pharmacological and biochemical parameters of study participants during treatment with tamoxifen

From: Hot flashes are not predictive for serum concentrations of tamoxifen and its metabolites

  Total Pre-menopausal Post-menopausal p-value
  n = 109 n = 56 n = 53  
n (%) n (%) n (%)
Pre-treatment history of hot flashes     0.04
   No 82 (75%) 47 (84%) 35 (66%)  
   Yes 27 (25%) 9 (16%) 18 (34%)  
Median frequency of hot flashes per week 21 21 21 0.77
   Range 0 - 168 0 - 168 0 - 168  
Average severity of hot flashes     0.56
   None 17 (16%) 9 (16%) 8 (15%)  
   Mild 22 (20%) 13 (23%) 9 (17%)  
   Moderate 55 (50%) 26 (46%) 29 (55%)  
   Severe 11 (10%) 7 (12%) 4 (8%)  
   Very severe 4 (4%) 1 (2%) 3 (6%)  
Median tamoxifen (ng/mL) 95.4 93.8 97.9 0.61
   Range 39.7 - 237 50.0 - 220 39.7 - 237  
Median N-desmethyltamoxifen (ng/mL) 181 177 187 0.82
   Range 82.3 - 532 94.3 - 532 82.3 - 439  
Median endoxifen (ng/mL) 9.12 8.59 9.16 0.75
   Range 1.73 – 22.6 1.73 – 20.3 2.14 – 22.6  
Median 4-hydroxytamoxifen (ng/mL) 1.69 1.77 1.43 0.91
   Range 0.74 - 4.23 0.74 - 4.23 0.78 - 3.51  
Median estradiol (pmol/L)     0.06
   <LLOQ* 70 33 37  
   43.0 – 67.0 12 6 6  
   67.0 – 361 14 8 6  
   >361 11 9 2  
   Missing 2 0 2  
CYP2D6 phenotype     0.66
   Extensive metabolizer 54 (50%) 28 (50%) 26 (49%)  
   Intermediate metabolizer 30 (28%) 19 (34%) 11 (21%)  
   Poor metabolizer 5 (5%) 2 (4%) 3 (6%)  
   Missing 20 (18%) 7 (12%) 13 (24%)  
  1. *<LLOQ is below the minimal quantification limit.