[Jackie07]

I looked up the database and found some new researches that could be the basis of my oncologist's decision. [He 'mailed' the sticky note "just want to make sure you are taking Tamoxifen" with a prescription a day after my appointment last summer - obviously not wanting to spend time explain... ]

http://www.cancer.gov/cancertopics/factsheet/Therapy/tamoxifen
Under 2. How does Tamoxifen work:
Although tamoxifen acts against the effects of estrogen in breast tissue, it acts like estrogen in other tissue. This means that women who take tamoxifen may derive many of the beneficial effects of menopausal estrogen replacement therapy, such as a decreased risk of osteoporosis.


Eur J Cancer. 2010 Jun;46(9):1580-7. Epub 2010 Apr 21.
Prolonged tamoxifen treatment increases relapse-free survival for patients with primary breast cancer expressing high levels of VEGF.
Sanchez BC, Sundqvist M, Fohlin H, Spyratos F, Nordenskjöld B, Stål O, Linderholm BK.
Karolinska Biomics Center, Karolinska Institute and University Hospital, Stockholm, Sweden.
Abstract
Previous retrospective studies have shown that high intratumoural levels of vascular endothelial growth factor (VEGF) correlate with an inferior outcome for patients treated with adjuvant tamoxifen. Our objectives were to validate the impact of VEGF on survival after adjuvant tamoxifen and to investigate the interaction between VEGF and treatment duration. For this purpose tumour homogenates from 402 patients with operable oestrogen receptor positive breast cancer (BC), treated with tamoxifen for 2 (n=149) or 5 years (n=253) as the only systemic adjuvant therapy were included. The median follow-up time for surviving patients was 9.8 years (range 0.5-14.8 years). Expression of VEGF was assessed by an enzyme-linked immunosorbent assay and investigated in relation to the standard BC parameters and survival. In the total population, higher VEGF was significantly correlated with shorter recurrence-free survival (RFS) (HR=1.63, 95%CI=1.11-2.39, p=0.010), breast cancer corrected survival (BCCS) (HR=1.82, 95%CI=1.13-2.93, p=0.014) and overall survival (OS) (HR=1.51, 95%CI=1.11-2.05, p=0.009). High VEGF was significantly associated with reduced RFS (HR=2.61, 95%CI=1.45-4.70, p=0.001) after two years of tamoxifen, whilst no difference was seen in patients treated for five years (HR=1.09, 95%CI=0.64-1.84, p=0.760). A statistically significant interaction was observed between high VEGF expression and improved RFS after 5-year tamoxifen (p=0.034). In concordance with previous studies, high VEGF was significantly correlated with shorter survival. We present data not reported previously revealing that patients expressing high levels of VEGF display a better outcome provided that tamoxifen is given for five years. Further studies on the impact of VEGF on a 5-year regimen are motivated.

Breast. 2010 Apr;19(2):76-83. Epub 2010 Jan 21.
Aromatase inhibitors versus tamoxifen as adjuvant hormonal therapy for oestrogen sensitive early breast cancer in post-menopausal women: meta-analyses of monotherapy, sequenced therapy and extended therapy.
Josefsson ML, Leinster SJ.
School of Medicine, Health Policy and Practice, University of East Anglia, Norwich NR4 7TJ, United Kingdom. m.josefsson@doctors.org.uk
Abstract
Adjuvant tamoxifen reduces relapses and prolongs survival in patients with oestrogen sensitive breast cancer. Development of resistance is however common. Tamoxifen can be given for a maximum of five years; although the risk of recurrences remains high after this period. This review examines nine randomised controlled trials including 28,632 women, which studied aromatase inhibitors (AIs) as an alternative to tamoxifen in three treatment settings: monotherapy (instead of tamoxifen), sequenced therapy (tamoxifen is switched to an AI) and extended therapy (following adjuvant tamoxifen). Disease free survival was significantly improved for monotherapy (HR 0.89, [95% CI 0.83-0.96] p = 0.002) and sequenced therapy (HR 0.72, [0.63-0.83] p < 0.00001). There was no difference in overall survival for monotherapy (HR 0.94, [0.82-1.08] p = 0.39) or extended therapy (HR 0.86 [0.79-1.16] p = 0.67). Importantly, overall survival was prolonged for patients who switched from tamoxifen to AI therapy (HR 0.78 95%CI 0.68-0.91, p = 0.001).
Copyright 2009 Elsevier Ltd. All rights reserved.