Thresholds for therapies: highlights of the St Gallen International Expert Consensus on the primary therapy of early breast cancer 2009

The 11(th) St Gallen (Switzerland) expert consensus meeting on the primary treatment of early breast cancer in March 2009 maintained an emphasis on targeting adjuvant systemic therapies according to subgroups defined by predictive markers. Any positive level of estrogen receptor (ER) expression is considered sufficient to justify the use of endocrine adjuvant therapy in almost all patients. Overexpression or amplification of HER2 by standard criteria is an indication for anti-HER2 therapy for all but the very lowest risk invasive tumours. The corollary is that ER and HER2 must be reliably and accurately measured. Indications for cytotoxic adjuvant therapy were refined, acknowledging the role of risk factors with the caveat that risk per se is not a target. Proliferation markers, including those identified in multigene array analyses, were recognised as important in this regard. The threshold for indication of each systemic treatment modality thus depends on different criteria which have been separately listed to clarify the therapeutic decision-making algorithm.

NCIC CTG MA.17: hormone receptor expression of in-breast recurrences and contralateral primary breast cancers arising on aromatase inhibitors

Abstract #1134

Background: The selective estrogen receptor modulators (SERMs) tamoxifen and raloxifene reduce the risk of ER+ (but not ER-) invasive breast cancers in healthy women at high risk for developing breast cancer. Aromatase inhibitors (AIs) given as adjuvant therapy to treatment-naïve or post-tamoxifen patients significantly reduce the risk of in-breast recurrences (IBRs) and contralateral breast cancers (CBCs) and are currently in clinical trials for breast cancer prevention (NCIC CTG MAP.3 and IBIS-II). It is hypothesized that SERMS inhibit promotion of ER+ breast cancer whereas AIs may reduce both ER+ and ER- breast cancer by inhibiting both tumor initiation and promotion. Little is known about the characteristics of IBRs and CBCs that arise on AI therapy. We present the ER/PR expression and clinicopathologic features of IBRs and CBCs that occurred on MA.17.
 Methods: We examined ER/PR status of IBRs and CBCs that arose on letrozole vs. placebo among women enrolled in MA.17, a placebo-controlled (PLAC) trial of letrozole (LET) following 5 years of tamoxifen in postmenopausal women with early stage breast cancer.
 Results: Seventy-one patients (pts) developed an IBR and 87 developed a CBC on trial. Consistent with results previously reported, fewer IBRs (LET 20 vs PLAC 51) and CBCs (LET 35 vs PLAC 52) were observed in the LET group. ER and PR status is currently available on 35 women with an IBR and 39 with a CBC. The majority of IBRs were ER+ in both the LET and PLAC groups (10/11 [91%] vs 18/24 [75%], respectively; p=NS) but numbers of both ER+ and – IBRs were less in LET group, suggesting that letrozole may decrease both ER+ and ER- IBRs. CBCs that arose on PLAC were more likely to be ER+ than on LET (16/22 [73%] vs 6/19 pts [32%], respectively; p=0.01), suggesting that letrozole predominantly prevents ER+ CBCs. Discordance in ER expression between primary breast cancer and IBRs among women randomized to LET vs. PLAC was observed in 1/11 [9%] and 6/24 [26%] women respectively (p=NS) and between primary breast cancer and CBCs in 12/18 pts [67%] vs. 6/21 [29%] women respectively (p=0.01). Other clinicopathologic characteristics such as grade, tumor size, PR, HER-2/neu, and nodal status of IBRs and CBCs will be presented at the meeting.
 Conclusion: Extended adjuvant endocrine therapy with letrozole results in fewer IBRs and CBCs compared with placebo as previously reported. Our data suggests that letrozole may decrease both ER+ and ER- IBRs. Letrozole appears to prevent ER+ CBCs but has little or no apparent effect on the development of ER- CBCs. These results need confirmation in the primary prevention trials of AIs.
 


Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1134.

Endoxifen, but not 4-hydroxytamoxifen, degrades the estrogen receptor in breast cancer cells: a differential mechanism of action potentially explaining CYP2D6 effect

Abstract #19

Background: Tamoxifen (TAM) is a standard endocrine therapy for the treatment of women with estrogen receptor (ER) positive breast cancer. TAM is activated by the cytochrome P450 2D6 enzyme system into two potent and active metabolites, 4-hydroxytamoxifen (4HT) and 4-hydroxy-N-desmethyl-tamoxifen (endoxifen). While human concentrations of 4HT are negligible and vary little in plasma (5-10 nM), endoxifen concentrations vary widely (10-180 nm), and women with genetically impaired CYP2D6 metabolism have significantly reduced endoxifen levels and a higher risk of breast cancer recurrence. Despite these observations, endoxifen's contribution to tamoxifen's overall drug effectiveness is uncertain.
 Methods: Using cells endogenously expressing ERa (MCF7, T47D) and cells stably transfected with ERa (Hs578T and U2OS), we examined the relative effects of TAM and its primary metabolites on ERa protein levels by western blotting, ERa transcriptional activity by luciferase reporter assays and real-time RT-PCR, and on ER positive breast cancer cell growth through the use of proliferation assays.
 Results: We have discovered that endoxifen induces ERa protein turnover through proteasomal degradation similar to that of ICI in a concentration and time-dependent manner. These findings are in stark contrast to TAM, N-desmethyl-tamoxifen (NDT) and 4HT, which stabilize the ER. Optimal degradation occurs only at endoxifen concentrations observed in human CYP2D6 extensive metabolizers (> 40 nM) and persists even in the presence of TAM (300 nM), 4HT (7 nM), and NDT (700 nM) at concentrations observed in patients receiving tamoxifen therapy. In contrast, reducing endoxifen concentrations to those observed in a CYP2D6 poor metabolizer (20 nM), without altering TAM, 4HT, and NDT, results in ER stabilization. High endoxifen concentrations (100-1000 nM) completely block estrogen (E2)-induced ER transcriptional activity even in the presence of TAM, 4HT, and NDT, while low endoxifen concentrations (20-40 nM) do not. Further, low concentrations of endoxifen (20 nM) do not significantly alter E2-induced cell proliferation; however, high concentrations of endoxifen (100-1000 nM) completely block this process. Discussion: Our data demonstrate that endoxifen is a potent anti-estrogen that targets ERa for proteasomal degradation, blocks ERa transcriptional activity and inhibits E2-induced breast cancer cell proliferation. Importantly, these effects of endoxifen are observed at concentrations found in CYP2D6 extensive metabolizers and are maintained even in the presence of TAM, 4HT and NDT. These studies suggest that endoxifen may be the primary metabolite responsible for tamoxifen's effectiveness in the treatment of ER positive breast cancer and provide the impetus to evaluate whether TAM-related side-effects, such as thrombo-embolism and endometrial hyperplasia/carcinoma, are inversely associated with a patient's ability to metabolically activate tamoxifen.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 19.

Intent-to-treat analysis of the placebo-controlled trial of letrozole for extended adjuvant therapy in early breast cancer: NCIC CTG MA.17

BACKGROUND

MA.17 evaluated letrozole or placebo after 5 years of tamoxifen and showed significant improvement in disease-free survival (DFS) for letrozole [hazard ratio (HR) 0.57, P = 0.00008]. The trial was unblinded and placebo patients were offered letrozole.

PATIENTS AND METHODS

An intent-to-treat analysis of all outcomes, before and after unblinding, on the basis of the original randomization was carried out.

RESULTS

In all, 5187 patients were randomly allocated to the study at baseline and, at unblinding, 1579 (66%) of 2383 placebo patients accepted letrozole. At median follow-up of 64 months (range 16-95), 399 recurrences or contralateral breast cancers (CLBCs) (164 letrozole and 235 placebo) occurred. Four-year DFS was 94.3% (letrozole) and 91.4% (placebo) [HR 0.68, 95% confidence interval (CI) 0.55-0.83, P = 0.0001] and showed superiority for letrozole in both node-positive and -negative patients. Corresponding 4-year distant DFS was 96.3% and 94.9% (HR 0.80, 95% CI 0.62-1.03, P = 0.082). Four-year overall survival was 95.1% for both groups. The annual rate of CLBC was 0.28% for letrozole and 0.46% for placebo patients (HR 0.61, 95% CI 0.39-0.97, P = 0.033).

CONCLUSIONS

Patients originally randomly assigned to receive letrozole within 3 months of stopping tamoxifen did better than placebo patients in DFS and CLBC, despite 66% of placebo patients taking letrozole after unblinding.

How well do standard prognostic criteria predict oncotype DX (ODX) scores?

576

Background: In node-negative, ER + breast cancer, gene expression profiling can identify level of risk and, in the case of ODX, may also identify pts with a higher chance of benefiting from adjuvant chemotherapy. Because the gene profile in ODX includes an assessment of ER, HER2, and proliferation, we hypothesized that clinicians using standardized criteria could discriminate risk (high versus low/intermediate) as specified by ODX. Methods: We identified Mayo Clinic patients with node-negative, ER + breast cancer, for whom ODX scores were available. Tumor slides were reviewed by an expert breast pathologist to confirm tumor size, histology, and tumor grade. Both ER and PR were quantitated; HER-2 was determined by IHC (FISH, if 2+). These clinical cases were presented to six academic oncologists, blinded to the ODX score, to predict ODX risk (low, intermediate, or high) and give their recommendation for chemotherapy (CTX) (yes/no). Afterwards, they were presented with the same cases with the actual ODX score, to give recommendations regarding CTX. Results: ODX scores in tumors from 31 patients were low in 18 pts, intermediate in 10 pts, and high in 3 pts. Concordance between predicted and actual ODX scores being low/intermediate vs high exceeded 87% for each oncologist. The most frequent discrepancies were actual low scores predicted as intermediate (31/80 discordant) and actual intermediate scores predicted as low (29/80 discordant). Overall agreement of predicted scores (high vs low/intermediate) among the oncologists was substantial (kappa=0.75, p<0.0001). CTX recommendations following provision of the ODX scores changed on average 18.2% (range 12.9%-25.8%) of the time, with slightly fewer changing for, versus against, a CTX recommendation. Conclusions: Our findings suggest that the proper evaluation and interpretation of traditional prognostic criteria will identify most node negative, ER + patients at high risk of recurrence (as predicted by ODX) but poorly discriminate low versus intermediate risk. The provision of ODX data changed the recommendation for CTX in approximately 20% of cases.

No significant financial relationships to disclose.

Competing causes of death in NCIC CTG MA.17, a placebo-controlled trial of letrozole as extended adjuvant therapy for breast cancer patients

540

Background: Risk of death from other malignancies (OM) and other causes (OC) than breast cancer (BC) increases with age. Effects of baseline factors on type of death were assessed with competing risks analyses. Methods: In NCIC CTG MA.17, 5,187 women free of recurrent breast cancer after 5 years of tamoxifen were randomized to letrozole (L, 2,593 women) or placebo (P, 2,594 women). The primary endpoint was disease free survival (DFS), and secondary, overall survival (OS). Follow-up was to October 9, 2005: median 3.9 years, range <0.1 to 7.0 years. Effects of competing risks were examined for endpoints of BC, OM, and OC for 11 baseline trial factors: treatment, age, menopausal status, duration of prior tamoxifen, adjuvant radiotherapy, bone fracture, osteoporosis, cardiovascular disease, hormone receptor status, nodal status, adjuvant chemotherapy. Lagakos’ hierarchical method (Lagakos, Appl. Statist. 1978; 27:235–241) was used to test for differential effects of baseline factors on type of death (BC, OM, OC). Results: Rate of censoring was 97.8%, with 256 deaths (BC, 102; OM, 50; OC, 100; unknown, 4). Non-breast cancer deaths accounted for 60% of known deaths; 72%, for those ≥70 years; and 48%, for those <70 years. Two baseline factors differentially affected type of death. Women with cardiovascular disease were more likely to die from OC (p=0.02), while those with osteoporosis were more likely to die of OM (p=0.03). Age and nodal status had directionally similar effects. Older women had shorter survival from all 3 causes of death (p=0.01). Lymph node positivity was associated with worse survival (p=0.003). Conclusions: Extended L provides similar proportional benefit in improving DFS for all ages of women (Muss ref abstract SABCS 2006). However, the magnitude of competing non-breast cancer, and non-treatment related, causes of death needs to be considered more frequently, since with early detection and improved therapies, breast cancer patients may increasingly be expected to survive their disease to die from another cause. The novel association between baseline osteoporosis and other malignancies is being explored quantitatively.

No significant financial relationships to disclose.

Pilot study of the impact of letrozole vs. placebo on breast density in women completing 5 years of tamoxifen

Breast density, a strong risk factor for breast cancer, is reduced by the anti-estrogen, tamoxifen (TAM). We examined whether aromatase inhibitor (AI) therapy results in further reductions in breast density among women completing 5 years of TAM. Among a sample of women with early-onset breast cancer who were randomized to letrozole (LET)(n=56) or placebo (PLAC)(n=48) after 5 years of TAM, we examine the change in percent density at 9-15 months as well as a per-year change in PD by treatment group. There was no difference in the adjusted mean change (-1.0%, LET; -0.3%, PLAC (P=0.58)) or the percentage change (-2.7%, LET; -3.0%, PLAC (P=0.96)) in PD between treatment groups at 9-15 months. Results were similar for longitudinal change (-0.68% per year, LET; -0.12% per year, PLAC (P=0.23)). Breast density does not appear to be a clinically relevant biomarker in women who already have low PD following 5 years of TAM.

Clinical outcomes of ethnic minority women in MA.17: a trial of letrozole after 5 years of tamoxifen in postmenopausal women with early stage breast cancer

BACKGROUND

Aromatase inhibitors are widely employed in the adjuvant treatment of early stage breast cancer. The impact of aromatase inhibitors has not been established in ethnic minority women.

PATIENTS AND METHODS

The purpose of this study was to evaluate the impact of letrozole on minority women in MA.17, a placebo-controlled trial of letrozole following 5 years of tamoxifen in postmenopausal women with early stage breast cancer. Retrospective comparison of disease-free survival (DFS), side effects, and mean changes in quality of life (QOL) scores from baseline between Caucasian and minority women was performed.

RESULTS

Minority (n = 352) and Caucasian (n = 4708) women were analyzed. There was no difference between these groups in DFS (91.6% versus 92.4% respectively for 4 year DFS). Letrozole, compared with placebo, significantly improved DFS for Caucasians (HR = 0.55; P < 0.0001) but not for minorities (HR = 1.39; P = 0.53). Among women who received letrozole, minorities had a significantly lower incidence of hot flashes (49% versus 58%; P = 0.02), fatigue (29% versus 39%; P = 0.005), and arthritis (2% versus 7%; P = 0.006) compared with Caucasians. Mean change in QOL scores for minority women who received letrozole demonstrated improved mental health at the 6-month assessment (P = 0.02) and less bodily pain at the 12-month assessment (P = 0.046).

CONCLUSION

Letrozole improved DFS in Caucasians but a definite benefit in minority women has not yet been demonstrated. Minority women tolerated letrozole better than Caucasians in terms of toxicity. These results need confirmation in other trials of aromatase inhibitors.

Updated analysis of NCIC CTG MA.17 (letrozole vs. placebo to letrozole vs placebo) post unblinding

550

Background: 5187 postmenopausal women were originally randomized to NCIC CTG MA.17 to receive letrozole (LET) or placebo (PLAC) after 5 years of tamoxifen. The hazard ratio (HR) for disease-free survival (DFS) was 0.58 (0.450.76, p=0.00004) after a median follow-up of 30 months (mo). The trial was unblinded in October 2003 after the first interim analysis. Women randomized to PLAC were offered LET at the time of unblinding. The goal of this analysis was to determine whether women switching from PLAC to LET benefit in terms of disease outcome and to evaluate treatment related toxicities. Methods: LET and PLAC-LET have been compared to PLAC, based on the hazard ratio and adjusting for baseline patient and disease variables including, among others, tumor size, nodal status and prior adjuvant chemotherapy. Results: Information about their follow-up treatment after unblinding was available on 2268 women originally assigned to PLAC and who were free of recurrence and alive at the time of unblinding. Among them, 1655 crossed over from PLAC to LET while 613 elected no treatment. With 54 mo f/up the HR for DFS was 0.31 (0.18, 0.55: p<0.0001) favoring patients who crossed over to LET compared to those who stayed on no treatment. The treatment switch was well tolerated with no significant difference in bone fractures or cardiovascular events. An updated analysis of DFS, DDFS and OS by nodal and tumor receptor status, prior chemotherapy, menopausal status at the start of tamoxifen, and duration of prior tamoxifen therapy will be presented at the meeting. Conclusion: Women with hormone dependent breast cancer prescribed LET after a prolonged delay from completing tamoxifen experienced a significant improvement in outcome (DFS, DDFS, OS) and should be considered for this therapy.

[Table: see text]

Cytochrome P450 2D6 status predicts breast cancer relapse in women receiving adjuvant tamoxifen (Tam)

504

Background: CYP2D6 genetic variants and concurrent administration of potent inhibitors (Inh) of the enzyme markedly reduce the plasma concentrations of endoxifen (Jin. JNCI 2005;97:30–9). We have shown that genetic variation in CYP2D6 is associated with a higher risk of relapse in Tam treated patients (pts) (Goetz. JCO 2005;23:9312–18), but the impact of CYP2D6 inhibition on Tam clinical outcome is unknown. Methods: Using the North Central Cancer Treatment Group 89–30–52 adjuvant Tam trial (1989–1994), we evaluated the effect of co-administration of CYP2D6 Inh and CYP2D6*4 genotype on relapse in pts receiving tam alone. Patient charts were reviewed at each randomizing site to record the following known CYP2D6 Inh: fluoxetine (F), paroxetine (P), sertraline (S), cimetidine (C), amiodarone (A), doxepin (D), ticlopidine (T) and haloperidol (H). Poor metabolizers (PM) were defined as pts who were CYP2D6 *4/*4 and/or known to receive a CYP2D6 Inh. Intermediate metabolizers (IM) were defined as WT/*4 without CYP2D6 Inh, and extensive metabolizers (EM) as WT/WT without CYP2D6 Inh. The association between CYP2D6 status and Tam clinical outcome was determined using the log-rank test. Multivariate Cox modeling was performed using traditional prognostic factors. Results: CYP2D6*4 genotype was obtained in 190 of 256 eligible pts, with a CYP2D6*4/*4 genotype frequency of 6.8% as described previously (Goetz JCO 2005). Medication history was available in 171/256 eligible pts and in 143/190 pts with CYP2D6 genotype. Eleven of 173 patients were concomitantly administered these CYP2D6 Inh: F(2), P(2), S(2), H(1), C(4), and D(1). The median duration of use was 2.5 yrs. Twenty-four pts met criteria for PM [13 by *4/*4 genotype and 11 by CYP2D6 Inh (7 WT/WT, 1 WT/*4, and 3 unknown genotype)], 21 for IM, and 102 for EM. Compared with either IM or EM, PMs had significantly worse time to recurrence and disease free survival in both the univariate (HR 2.5, p=0.02; and 2.2, p=0.01) and multivariate (HR 2.7, p=0.01; and HR 2.2 p=.02) analyses utilizing tumor size, nodal status, and tumor grade. Conclusion: Our data indicate that CYP2D6 status can be used to identify pts who should receive tam therapy and tam treated pts should not be co-administered potent CYP2D6 inhibitors.

No significant financial relationships to disclose.

NCIC CTG MA.17: Tolerability of letrozole among ethnic minority women

6018

Background: Disease free survival was significantly improved in women receiving letrozole after standard adjuvant tamoxifen in the MA.17 trial. Based on the results of MA.17 and of other trials of aromatase inhibitors in early stage breast cancer, chronic aromatase inhibitor therapy, in postmenopausal women free of breast cancer recurrence, is now being widely employed. We analyzed the toxicity of letrozole according to ethnic status among women enrolled in MA.17. Methods: The chi-square test was used for comparison of rates of side effects between the two groups, Caucasian vs. ethnic minority (defined as all non-Caucasians). In a subset of women, quality of life (QOL) was assessed by the SF-36 Health Survey. Mean change scores in QOL from baseline were compared between groups for summary measures and domains using the Wilcoxon test. Results: 352 minority women and 4,708 Caucasians were enrolled in MA.17, of which 183 minority women and 2,339 Caucasians were randomized to receive letrozole. Caucasians were older than minority women and had a slightly longer duration of treatment with prior tamoxifen. Tumor size and nodal status were not significantly different between the two groups. In women who received letrozole, minority women had significantly lower incidence of hot flashes (49% vs. 58%; p = 0.02), fatigue (29% vs. 39%; p = 0.005), and arthritis (2% vs. 7%; p = 0.006) compared with Caucasians. Mean QOL change scores of SF-36 domains for women who received letrozole were not different but minority women had better mental health at 6 month assessment (p = 0.02) and worse bodily pain at 12 month assessment (p = 0.046). Conclusions: Minority women tolerated letrozole considerably better than Caucasians in the MA.17 trial. These preliminary findings suggest that minority women respond differently to letrozole in terms of toxicity. Recent demonstration of genotypic variations in the aromatase gene in different ethnic groups plus likely pharmacogenomic differences suggests that further research is needed to clarify the clinical outcomes of aromatase inhibition in women of diverse ethnicities. Future research strategies should focus on examining in vivo genotype-phenotype correlations to determine the effects of genetic variation on response to anticancer therapy and on toxicities and end-organ effects.

[Table: see text]

A phase II trial of a combination of pemetrexed and gemcitabine in patients with metastatic breast cancer: an NCCTG study

PURPOSE

This phase II study was undertaken to define the efficacy and toxicity of pemetrexed in combination with gemcitabine in patients with metastatic breast cancer.

PATIENTS AND METHODS

Patients with measurable metastatic breast cancer who had previously received an anthracycline and a taxane in either the adjuvant or metastatic setting were treated with gemcitabine 1250 mg/m2 (intravenous; days 1 and 8) and pemetrexed 500 mg/m2 (intravenous; day 8) every 21 days.

RESULTS

Fifty-nine patients received a median of five cycles (range one to 22) of treatment and were followed until death or for a median of 28 months (range 19.4-36.6) among living patients. Fourteen partial responses for an overall response rate of 24% [95% confidence interval (CI) 16% to 39%] were documented. Nine (15%; CI 5% to 32%) patients had stable disease for >6 months. The median survival time was 10.3 months (95% CI 8.3-18.9) and the 1 year survival rate was 49% (95% CI 38% to 64%). The median time to progression was estimated to be 3.7 months (95% CI 2.3-5.3). The most common grade 3 or 4 toxicities were neutropenia and thrombocytopenia in 83% and 27% of patients, respectively. Fourteen percent of patients experienced febrile neutropenia. Other common grade 3 or 4 non-hematological toxicities included fatigue (17%), dyspnea (15%), rash (7%) and anorexia (5%).

CONCLUSIONS

The combination of pemetrexed and gemcitabine is clinically active, with an overall response rate of 24% in patients with metastatic breast cancer who have previously been treated with an anthracycline and a taxane. Myelosuppression (66% grade 4 neutropenia and 14% febrile neutropenia) was the major treatment-related toxicity observed for this combination.

The influence of letrozole on serum lipid concentrations in postmenopausal women with primary breast cancer who have completed 5 years of adjuvant tamoxifen (NCIC CTG MA.17L)

BACKGROUND

The purpose of this study was to evaluate changes in serum lipid parameters {cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides and lipoprotein(a) [Lp(a)]}, in postmenopausal women receiving letrozole or placebo after adjuvant tamoxifen for early stage breast cancer (NCIC CTG MA.17L).

PATIENTS AND METHODS

MA.17L is a substudy of MA.17, a randomized, double-blind, placebo-controlled trial of letrozole 2.5 mg taken daily for 5 years in postmenopausal women with primary breast cancer completing approximately 5 years of prior adjuvant tamoxifen. Patients consenting to participate in this companion study had blood drawn and lipid parameters (total cholesterol, HDL cholesterol, LDL cholesterol, Lp(a), triglycerides) evaluated at baseline, 6 months, 12 months and yearly thereafter until completion of protocol therapy. It was required that women be non-hyperlipidemic and not taking lipid-lowering drugs at time of entry on this trial.

RESULTS

Three hundred and forty seven women were enrolled in the study. The letrozole and the placebo groups demonstrated marginally significant differences in the percentage change from baseline in HDL cholesterol at 6 months (P=0.049), in LDL cholesterol at 12 months (P=0.033) and triglycerides at 24 months (P=0.036). All comparisons of lipid parameters at other time points were not significantly different between the two treatment groups. No statistically significant differences in the number of patients exceeding the thresholds defined for the lipid parameters were found between the two treatment groups.

CONCLUSIONS

The MA.17 trial demonstrated a significant improvement in disease-free survival with the use of letrozole as extended adjuvant therapy post tamoxifen. Results from this study suggests that letrozole does not significantly alter serum cholesterol, HDL cholesterol, LDL cholesterol, triglycerides or Lp(a) in non-hyperlidiemic postmenopausal women with primary breast cancer treated up to 36 months following at least 5 years of adjuvant tamoxifen therapy. These findings further support the tolerability of extended adjuvant letrozole in postmenopausal women following standard tamoxifen therapy.

Primary breast sarcoma: clinicopathologic series from the Mayo Clinic and review of the literature

Primary sarcomas of the breast are extremely rare, with less than 0.1% of all malignant tumours of the breast. Mayo Clinic Surgical Pathology database was searched for all breast sarcoma from 1910 to 2000. Pathology reports and slides were reviewed and tumour types were determined. Metaplastic carcinomas and phyllodes tumours were excluded. There were 25 women ranging in age 24-81 years (mean 45 years). All but one patient presented with a palpable lump. Mastectomy was performed in 19 patients and lumpectomy in five patients. Histopathological diagnoses were fibrosarcoma (six), angiosarcoma (six), pleomorphic sarcoma (six), leiomyosarcoma (two), myxofibrosarcoma (three), hemangiopericytoma (one) and osteosarcoma (one). Tumour size ranged from 0.3 to 12 cm (mean 5.7). Low-grade lesions were observed in 10 cases and high-grade in 15. Overall, mean follow-up was 10.5 years. Local recurrence was observed in 11 patients and ranged from 2 to 36 months (mean 15 m), while distant metastasis was observed in 10 patients (40%) affecting lungs, bones, liver, spleen, and skin. Of the 25 patients, 12 have died of disease and six of other causes. Five-year overall (OS) and cause-specific survival (CSS) were 66 and 70%, respectively. OS and DFS at 5 years were 91% for tumours < or =5 cm and 50% for tumours >5 cm. Tumour size was significantly associated with OS (risk ratio=1.3 per 1 cm increase; 95% CI, 1.02-1.7; P=0.036). There was no significant difference in OS or CSS between low- and high-grade lesions. In this series, tumour size was a more valuable prognostic factor than tumour grade.

A randomized phase II study of sequential docetaxel and doxorubicin/cyclophosphamide in patients with metastatic breast cancer

BACKGROUND

Docetaxel has yielded promising response rates as a component of doxorubicin-based combination schedules in patients with metastatic breast cancer, including docetaxel/doxorubicin and docetaxel/doxorubicin/cyclophosphamide (AC). This randomized two-stage phase II study was conducted to evaluate sequential treatment with docetaxel and AC as first-line treatment in patients with recurrent or metastatic breast cancer previously untreated with chemotherapy for metastatic disease.

PATIENTS AND METHODS

Thirty-three patients were randomized to either docetaxel (100 mg/m(2)) on day 1 of a 21-day cycle for three cycles followed by AC (60/600 mg/m(2)) on day 1 of a 21-day cycle for three cycles (n = 17) or vice-versa (n = 16), without prophylactic granulocyte colony-stimulating factor support. In addition, we compared pre-treatment serum sErbB1 and sErbB2 protein concentrations with that of an age- and menopausal status-matched group of healthy women, and examined changes in serum sErbB1 and sErbB2 protein concentrations in these two treatment schedules. Data from each one of the two arms of the trial (docetaxel then AC, or AC and then docetaxel) were analyzed separately.

RESULTS

Enrollment was suspended after the first-stage of accrual, based on statistical design. Confirmed objective response rates after six cycles of treatment were 35% [95% confidence interval (CI) 14% to 62%] with docetaxel then AC and 38% (95% CI 15% to 65%) with AC then docetaxel. Dose reductions were frequent and mostly due to grade 4 neutropenia. Median survival time was 2.5 years in the docetaxel then AC group, and 1.1 years in the AC then docetaxel group. Serum sErbB1 concentrations were not significantly different between the study patients and healthy women, and did not change significantly after three and six cycles of treatment. In contrast, serum sErbB2 concentrations were significantly higher in the study patients compared with healthy women and tended to decrease after three and six cycles of treatment.

CONCLUSIONS

Response rates at the end of six cycles of treatment, which led to termination of accrual after the first stage using either the sequence of docetaxel first or docetaxel after AC chemotherapy, were lower than anticipated. However, median survival times and median progression-free survival times are similar to those reported in other studies. These data further suggest that additional studies to assess whether serum sErbB2 concentrations are useful predictors of responsiveness to chemotherapy are warranted.

Current status of adjuvant endocrine therapy for breast cancer

Adjuvant endocrine therapy is a vitally important modality for treatment of women with resected hormone-sensitive breast cancer as indicated by the presence of estrogen and/or progesterone receptors in the tumor. It is not recommended in those patients whose tumors lack these hormone receptors. Tamoxifen for 5 years has been shown to reduce the risk of recurrence and death irrespective of menopausal status or use of adjuvant chemotherapy. In postmenopausal women, the major research emphasis relates to the use of third-generation aromatase inhibitors in sequence with, instead of, and in combination with tamoxifen. In premenopausal women, ovarian ablation/suppression has demonstrated efficacy comparable with some chemotherapy regimens, but its role in women receiving chemotherapy remains to be determined.

Prolonged survival associated with early lymphocyte recovery after autologous hematopoietic stem cell transplantation for patients with metastatic breast cancer

Early absolute lymphocyte count (ALC) recovery at day 15 post-autologous stem cell transplantation (ASCT) is a powerful prognostic indicator for survival in multiple myeloma and non-Hodgkin's lymphoma. The relationship of ALC with clinical outcomes in metastatic breast cancer is unknown. We evaluated all 29 patients with metastatic breast cancer who underwent ASCT at the Mayo Clinic, Rochester, Minnesota, from 1994 to 1999. The ALC threshold was set at 500 cells/microl on day 15 post-ASCT based on previous experience with hematologic malignancies. All patients were followed for a minimum of 2 years or until death, with a median follow-up for living patients of 2.25 years. Of the 29 patients, 17 have died with disease progression, two are alive and have progressed, and 10 are alive without progression. The median overall and progression-free survival times were significantly better for the 20 patients with ALC > or = 500 cells/microl compared with the nine patients with ALC <500 cells/microl (not reached vs 14 months, P < 0.0001; 24 vs 7 months, P < 0.0015, respectively). In conclusion, ALC > or = 500 cells/microl on day 15 post-ASCT was associated with significantly better survival in patients with metastatic breast cancer, suggesting the importance of early immune recovery post-ASCT in these patients.