Immunohistochemical Phenotype after 20-Year Follow-Up of the Royal Marsden Tamoxifen Breast Cancer Prevention Trial (RMTBCPT)

Background: 20-yrs after starting the randomized, double-blind RMTBCPT (13-year median follow-up) 186 women developed invasive breast cancer, 82 on tamoxifen and 104 on placebo1. There was a significant reduction in the incidence of invasive ER+ but not ER- breast cancer that was significant after but not during the 8yr treatment period. The phenotype of ER+ breast cancer is highly variable. We have therefore assessed PgR, HER2, EGFR and Ki67 expression in as many as possible of these tumours.Methods: Tumour blocks were available on 154 participants, 65 on tamoxifen and 89 on placebo a similar distribution to the whole population. Staining was conducted using the following antibodies: ER, clone 6F11(Vector); PgR, clone 16 (Vector); HER2, HercepTest + K5207 (Dako), FISH PathVysion (Abbott) for IHC 2+ cases; EGFR, clone 31G7 (Invitrogen); Ki67 clone Mib1(Dako). ER and PgR were quantified as H-scores, HER2 and EGFR as + or –, and Ki67 as % cells staining.Results: There were 47 and 18 ER+ and ER- tumours in the tamoxifen arm vs 76 and 13 in the placebo arm, showing a 37% (95% CI 10- 57%, p=0.01) reduction of ER+ tumours which was essentially the same as that in the whole population1.There were 38 and 27 PgR+ and PgR- tumours in the tamoxifen arm vs 58 and 31 in the placebo arm, showing a 33% (95% CI 0-56%, p=0.05) reduction of PgR+ tumours. The distribution of ER/PgR tumours according to arm and time on trial at tumour diagnosis is shown in the table (there were no ER-PgR+ cases).The decrement in ER+ tumours was predominantly in ER+PgR+ cases after 8yrs but extended to ER+PgR- cases. It is important to note that the post 8yr tumour phenotype cannot be affected by continued exposure to tamoxifen. ER levels were significantly lower in the tamoxifen-treated group even among tumours presenting as ER+ (median H-score 123 vs 161, p=0.02). There were 9 and 6 HER2+ and 11 and 12 EGFR+ cases in the tamoxifen and placebo arms, respectively (p=NS for both). The mean (95%CI) levels of Ki67 were 8.4% (6.3-11.1) and 8.5% (6.8-10.6) in the 2 arms, respectively.Discussion: The decrement in ER+ tumours in the tamoxifen-treated women was restricted to the post-treatment period and was similar to that seen in the overall population1. Among the ER+ group there was a similar proportional reduction of PgR+ and PgR- tumours by tamoxifen.There was no evidence of enhanced HER2 or EGFR expression or increased proliferation in tumours developing in the tamoxifen arm but ER expression was reduced even among ER+ tumours.1Powles et al, JNCI, 2007;99:283-90. Time on trialPlaceboTamoxifenER+PgR+<8 years2622ER+PgR+>8 years3216ER+PgR-<8 years106ER+PgR->8 years83ER-PgR-<8 years711ER-PgR->8 years67All<8 years4339All>8 years4626 Supported by the Da Costa International Fund for Breast Cancer Prevention

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1046.

Interim analysis of the incidence of breast cancer in the Royal Marsden Hospital tamoxifen randomised chemoprevention trial

BACKGROUND

Tamoxifen, a drug with antioestrogenic effects, is predicted to prevent the occurrence of breast cancer. We have undertaken a trial of tamoxifen in healthy women who are at increased risk of breast cancer because of family history. We report a planned interim analysis.

METHODS

Between October, 1986, and April, 1996, we accrued 2494 healthy women aged between 30 and 70 with a family history of breast cancer. They have been randomised (double blind) to receive tamoxifen 20 mg per day orally or placebo for up to 8 years. Follow-up included clinical assessment, annual mammography, and assessment of toxicity and compliance. The primary endpoint was the occurrence of breast cancer, which was analysed on an intention-to-treat basis with a survival curve.

FINDINGS

With a median follow-up of 70 months, 2471 women (tamoxifen 1238, placebo 1233) were suitable for analysis. The groups were evenly matched at baseline, and compliance was good. The overall frequency of breast cancer is the same for women on tamoxifen or placebo (tamoxifen 34, placebo 36, relative risk 1.06 [95% CI 0.7-1.7], p=0.8). Participants who were already on hormone-replacement therapy when they entered the study had an increased risk of breast cancer compared with non-users. Those participants who started such therapy while on trial had a significantly reduced risk. The safety profile of tamoxifen was as expected.

INTERPRETATION

We have been unable to show any effect of tamoxifen on breast-cancer incidence in healthy women, contrary to the report from the NSABP-P1 study showing a 45% reduction in healthy women given tamoxifen versus placebo. Differences in the study populations for the two trials may underlie these conflicting findings: eligibility in our trial was based predominantly on a strong family history of breast cancer whereas in the NSABP trial was mostly based on non-genetic risk factors. The importance of oestrogen promotion may vary between such populations.

The effects of norethisterone on endometrial abnormalities identified by transvaginal ultrasound screening of healthy post-menopausal women on tamoxifen or placebo

Tamoxifen (tam) is used extensively for treatment of patients with breast cancer and is being evaluated for chemoprevention in healthy women. It has, however, been reported to increase the risk of endometrial cancer in post-menopausal women, probably by an oestrogenic effect on the endometrium. It also causes endometrial cysts and polyps. The aims of this study were to identify the incidence of endometrial thickening, polyps and cysts by transvaginal ultrasound (TVUS) screening of a population of post-menopausal healthy women in the Royal Marsden tamoxifen chemoprevention trial and to evaluate the possible benefit from the use of intermittent norethisterone (NE) in women with persistent changes. Since 1990, we have undertaken regular TVUS, using an endovaginal B mode probe, of the 463 post-menopausal women in the trial randomized to tam (20 mg day(-1)) or placebo (plac), without breaking the randomization code. Endometrial thickening (ET) was defined as > or = 8 mm at the widest point across the myometrial cavity in the longitudinal plane, including any stromal changes. Cystic changes were defined as more than one hypoechogenic area > 1 mm. Polyps were identified using saline hydrosonography. Oral NE (2.5 mg day(-1)) was used for 21 days out of 28 for three consecutive cycles by women with persistent endometrium > or = 8 mm, including cystic and polypoid changes. TVUS was repeated after the three courses to evaluate any change caused by NE and endometrial biopsies, including hysteroscopy, was performed on those women with persistent abnormalities. A persistent ET > or = 8 mm was identified in 56 (24%) of the 235 women on tamoxifen compared with only 5 (2%) of 228 women on placebo (P <0.0005). Stromal changes, including cysts, were detected in 36 (15%) and polyps in 26 (11%) of the women on tamoxifen compared with only two (< 1%) of the women on placebo (P << 0.0005). After 3 months of cyclical norethisterone, 39 of 47 women (83%) on tamoxifen had persistent ultrasound changes. However, 45 (96%) had a progesterone withdrawal bleed. Hysteroscopy was performed in 39 women on tamoxifen (28 endometrial biopsy, 15 polypectomy), five of whom had histological evidence of a proliferative endometrium and a further three had an atypical hyperplastic endometrium (one of whom had a focus of invasive carcinoma). The cysts and polyps which were detected in women on tam could not be reversed by NE and were presumably stromal and not of malignant risk. However, 96% of the women had withdrawal NE bleeding, indicating an oestrogenically primed endometrium which could be a mechanism for an increased risk of endometrial cancer. Further studies are required to ascertain whether a progestin would protect against this risk. As in other studies, these results indicate that any increased risk of endometrial cancer caused by tamoxifen is low, and that TVUS screening is probably not justified for asymptomatic women on tamoxifen.

Reprogramming of telomerase by expression of mutant telomerase RNA template in human cells leads to altered telomeres that correlate with reduced cell viability

Telomerase synthesizes telomeric DNA by copying the template sequence of its own RNA component. In Tetrahymena thermophila and yeast (G. Yu, J. D. Bradley, L. D. Attardi, and E. H. Blackburn, Nature 344:126-131, 1990; M. McEachern and E. H. Blackburn, Nature 376:403-409, 1995), mutations in the template domain of this RNA result in synthesis of mutant telomeres and in impaired cell growth and survival. We have investigated whether mutant telomerase affects the proliferative potential and viability of immortal human cells. Plasmids encoding mutant or wild-type template RNAs (hTRs) of human telomerase and the neomycin resistance gene were transfected into human cells to generate stable transformants. Expression of mutant hTR resulted in the appearance of mutant telomerase activity and in the synthesis of mutant telomeres. Transformed cells were not visibly affected in their growth and viability when grown as mass populations. However, a reduction in plating efficiency and growth rate and an increase in the number of senescent cells were detected in populations with mutant telomeres by colony-forming assays. These results suggest that the presence of mutant telomerase, even if coexpressed with the wild-type enzyme, can be deleterious to cells, likely as a result of the impaired function of hybrid telomeres.

Effect of tamoxifen on bone mineral density measured by dual-energy x-ray absorptiometry in healthy premenopausal and postmenopausal women

PURPOSE

Tamoxifen is an effective treatment for metastatic and primary breast cancer and is now being evaluated as a chemoprevention agent in healthy women. Any long-term effects on estrogen-sensitive tissues such as bone may have important therapeutic implications.

METHODS

We measured bone mineral density (BMD) in the lumbar spine and hip using dual-energy x-ray absorptiometry (DXA) in premenopausal and postmenopausal healthy women who participated in our placebo-controlled tamoxifen chemoprevention of breast cancer trial.

RESULTS

BMD data are now available from 179 women for this analysis. In premenopausal women, BMD decreased progressively in the lumbar spine (P < .001) and in the hip (P < .05) for women on tamoxifen, but not those on placebo. The mean annual loss in lumbar BMD per year over the 3-year study period in tamoxifen-treated compliant women who remained premenopausal throughout the study period was 1.44% (1.88% calculated on an intent-to-treat basis) compared with a small gain of 0.24% per annum for women on placebo (P < .001). Tamoxifen had the opposite effect in postmenopausal women. The mean annual increase in BMD for women on tamoxifen was 1.17% in the spine (P < .005) and 1.71% in the hip (P < .001) compared with a noninsignificant loss for women on placebo.

CONCLUSION

These results indicate that tamoxifen treatment is associated with a significant loss of BMD in premenopausal women, whereas it prevents bone loss in postmenopausal women. These adverse and beneficial effects of tamoxifen should be considered in the assessment of the therapeutic benefits for both the adjuvant treatment and the chemoprevention of breast cancer.

Phase I study of mitozantrone, methotrexate and mitomycin with granulocyte colony-stimulating factor (filgrastim) in patients with advanced breast cancer

The combination of mitozantrone, methotrexate and mitomycin (3M) gives a response rate of around 50% in patients with advanced breast cancer. The predominant toxicity is haematological. In this study, previously untreated patients were given 3M with increasing doses of mitozantrone (7-14 mg m-2) with recombinant human granulocyte colony-stimulating factor (metHuG-CSF) (filgrastim) to prevent marrow toxicity. Doses administered were 7 mg m-2 mitomycin i.v. 6 weekly, methotrexate i.v. 35 mg m-2 (maximum 50 mg) 3 weekly and mitozantrone i.v. 3 weekly as follows: 7 mg m-2, six patients (group 1); 10 mg m-2, six patients (group 2); 12 mg m-2, six patients (group 3); 14 mg m-2, six patients (group 4); all on day 1 for six cycles at the assigned dose. All patients received filgrastim (Amgen 0.3 mg ml-1) at a dose of 5 micrograms kg-1 subcutaneously daily on days 4-17 of each cycle. All treatment was given on an out-patient basis. A total of 24 patients were entered into the study. The median age was 63 years (range 48-75). ECOG performance status was 0 in ten, 1 in 11 patients and 2 in three patients. Locoregional disease alone was present in seven patients. The remainder had one or more sites of metastases. The actual dose administered to the 24 patients was as follows. The six patients in group 1 all completed six courses of treatment as per protocol. In group 2, three patients completed six courses, two stopped because of toxicity after one and four courses and one had progressive disease after one course. In group 3, three patients completed and three stopped early because of progressive disease. In group 4, two patients completed, one progressed after four courses and three responding patients stopped treatment because of toxicity. The maximum tolerated dose of mitozantrone in the 3M combination was 12 mg m-2. The use of filgrastim with increasing doses of chemotherapy prevents neutropenia, but other toxicities, namely thrombocytopenia and lethargy, then become dose limiting.

Adjuvant aminoglutethimide for postmenopausal patients with primary breast cancer: analysis at 8 years

PURPOSE

The study purpose was to evaluate aminoglutethimide (AG) as adjuvant therapy in patients with primary node-positive breast cancer in a randomized double-blind placebo-controlled trial.

PATIENTS AND METHODS

In a multicenter trial, 354 postmenopausal women with early breast cancer and histologically confirmed positive axillary lymph nodes were randomized after surgery to received aminoplac. Patients were prescribed either AG 250 mg four times per day and hydrocortisone 20 mg twice per day or placebos of identical appearance for 2 years.

RESULTS

After a median follow-up of 8.1 years, there has been no overall benefit for AG in terms of either event-free survival or overall survival (OS). However, the results are consistent with interim analyses with a significantly improved event-free survival for patients who received AG for up to 4 years, although this benefit subsequently disappears. Similarly, there is an improved OS for patients who received AG for up to 4 years, but this also subsequently disappears. There was a marginal advantage for estrogen receptor (ER)-positive patients who received AG (n = 74; P = .054). There was no difference in the sites of relapse. There was a significant increase in toxicity for patients who received AG.

CONCLUSION

The lack of survival benefit with long-term follow-up for AG may indicate that aromatase inhibitors have less of an impact on early breast cancer than tamoxifen and may imply different biologic mechanisms of action.

Immunohistochemical localization of c-erbB-2 in human breast carcinomas

This study was carried out to assess the utility of antibodies raised to synthetic peptides of the predicted sequence of the c-erbB-2 gene product to identify immunocytochemically those tumours overexpressing this putative transmembrane receptor. Staining with rabbit antiserum 21N gave the best correlation with gene amplification and did not stain the membrane of any of the normal tissues at the dilution which strongly stained the membrane of any of the normal tissues at the dilution which strongly stained the amplified tumours. No significant correlation was found with lymph node involvement, epidermal growth factor receptor status or with oestrogen receptor levels. Of the 12 out of 34 cases which demonstrated c-erbB-2 gene amplification in the primary tumour, two had lymph node metastases which were also positive immunocytochemically. Fourteen other cases which had lymph node metastases were negative in the primary tumour and in the metastases. These tumours all showed strong membrane positivity. A comparison of modified methacarn and formol saline fixation demonstrated an increased sensitivity with the former, but the staining pattern was unaltered. This small but extensively studied group of cases has indicated that increased c-erbB-2 protein can be identified routinely in fixed tissue sections, making it possible to carry out extensive studies to look for clinical correlates, but also to assess the stage in tumour progression at which the increased expression occurs and whether it correlates with any potentially premalignant condition.