Combined chemo-hormonal therapy in breast cancer: a hypothesis

Concurrent vs sequential adjuvant chemotherapy and hormone therapy in breast cancer: a multicenter randomized phase III trial

BACKGROUND

The most appropriate timing of chemotherapy and hormone therapy administration is a critical issue in early breast cancer patients. The purpose of our study was to compare the efficacy of concurrent vs sequential administration of adjuvant chemotherapy and tamoxifen.

METHODS

Women with node-positive primary breast cancer were randomly assigned to receive tamoxifen (20 mg/d for 5 years) during (concurrent arm) or after (sequential arm) adjuvant chemotherapy. Chemotherapy consisted of alternating regimens of cyclophosphamide, epidoxorubicin, and 5-fluorouracil and cyclophosphamide, methotrexate, and 5-fluorouracil every 21 days for a total of 12 cycles. The primary endpoint was overall survival (OS), and secondary endpoints were toxic effects and disease-free survival (DFS). No provision for interim analyses was made in the original study protocol. Survival curves were estimated by the Kaplan-Meier method. Multivariable Cox regression models, adjusted for age, menopausal status, tumor stage, and lymph node and hormone receptor status, were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). All statistical tests were two-sided.

RESULTS

From 1985 to 1992, 431 patients were randomly assigned and studied according to the intention-to-treat principle. After a maximum of 15.4 years of follow-up (median 12.3 years), the estimated actuarial 10-year OS was equivalent for the two study arms (concurrent arm: 111 patients, 66%, 95% CI = 59% to 72%; sequential arm: 114 patients, 65%, 95% CI = 59% to 72%, P = .86). No differences in DFS and toxic effects were evident. Four interim analyses were performed, but no alpha error adjustment was necessary because of the largely negative results of this final analysis (sequential vs concurrent arm: HR of death = 1.06, 95% CI = 0.78 to 1.44, P = .76; HR of relapse = 1.16, 95% CI = 0.88 to 1.52, P = .36).

CONCLUSIONS

No statistically significant differences in OS, DFS, and toxic effects between concurrent and sequential adjuvant chemo- and hormone therapies were observed. Our study does not support the superiority of one schedule of chemo- and hormone-therapy administration over the other. However, because of the limited statistical power of the study, these results must be considered with caution.

Adjuvant chemotherapy and timing of tamoxifen in postmenopausal patients with endocrine-responsive, node-positive breast cancer: a phase 3, open-label, randomised controlled trial

BACKGROUND

Tamoxifen is standard adjuvant treatment for postmenopausal women with hormone-receptor-positive breast cancer. We assessed the benefit of adding chemotherapy to adjuvant tamoxifen and whether tamoxifen should be given concurrently or after chemotherapy.

METHODS

We undertook a phase 3, parallel, randomised trial (SWOG-8814, INT-0100) in postmenopausal women with hormone-receptor-positive, node-positive breast cancer to test two major objectives: whether the primary outcome, disease-free survival, was longer with cyclophosphamide, doxorubicin, and fluorouracil (CAF) given every 4 weeks for six cycles plus 5 years of daily tamoxifen than with tamoxifen alone; and whether disease-free survival was longer with CAF followed by tamoxifen (CAF-T) than with CAF plus concurrent tamoxifen (CAFT). Overall survival and toxicity were predefined, important secondary outcomes for each objective. Patients in this open-label trial were randomly assigned by a computer algorithm in a 2:3:3 ratio (tamoxifen:CAF-T:CAFT) and analysis was by intention to treat of eligible patients. Groups were compared by stratified log-rank tests, followed by Cox regression analyses adjusted for significant prognostic factors. This trial is registered with ClinicalTrials.gov, number NCT00929591.

FINDINGS

Of 1558 randomised women, 1477 (95%) were eligible for inclusion in the analysis. After a maximum of 13 years of follow-up (median 8.94 years), 637 women had a disease-free survival event (tamoxifen, 179 events in 361 patients; CAF-T, 216 events in 566 patients; CAFT, 242 events in 550 patients). For the first objective, therapy with the CAF plus tamoxifen groups combined (CAFT or CAF-T) was superior to tamoxifen alone for the primary endpoint of disease-free survival (adjusted Cox regression hazard ratio [HR] 0.76, 95% CI 0.64-0.91; p=0.002) but only marginally for the secondary endpoint of overall survival (HR 0.83, 0.68-1.01; p=0.057). For the second objective, the adjusted HRs favoured CAF-T over CAFT but did not reach significance for disease-free survival (HR 0.84, 0.70-1.01; p=0.061) or overall survival (HR 0.90, 0.73-1.10; p=0.30). Neutropenia, stomatitis, thromboembolism, congestive heart failure, and leukaemia were more frequent in the combined CAF plus tamoxifen groups than in the tamoxifen-alone group.

INTERPRETATION

Chemotherapy with CAF plus tamoxifen given sequentially is more effective adjuvant therapy for postmenopausal patients with endocrine-responsive, node-positive breast cancer than is tamoxifen alone. However, it might be possible to identify some subgroups that do not benefit from anthracycline-based chemotherapy despite positive nodes.

FUNDING

National Cancer Institute (US National Institutes of Health).

Additive antitumor effect of concurrent treatment of 4-hydroxy tamoxifen with 5-fluorouracil but not with doxorubicin in estrogen receptor-positive breast cancer cells

PURPOSE

The sequential addition of tamoxifen (TAM) to chemotherapy seems superior to its concurrent addition in patients with breast cancer. This study was conducted to clarify the hypothesis that there are differential interactions among TAM and chemotherapeutic agents.

METHODS

Estrogen receptor (ER)-alpha-positive or -negative breast cancer cells were treated with 4-hydroxy TAM (4OHT), 5-fluorouracil (FU) and/or doxorubicin (Dox). Changes in the expression levels of genes related to sensitivity and resistance to TAM, 5-FU or Dox were tested.

RESULTS

Concurrent treatment of 4OHT with 5-FU but not with Dox additively inhibited the growth of ER-alpha-positive cells. 5-FU did not change the expression levels of any tested genes related to either sensitivity or resistance to TAM. Although Dox did not change the expression levels of any genes related to the sensitivity to TAM, Dox significantly increased the expression levels of some genes related to TAM resistance, Eph A-2, ER-beta, Fos and vascular endothelial growth factor. 4OHT significantly decreased thymidilate synthase (TS) activity.

CONCLUSIONS

Although the antitumor effect of concurrent 4OHT and 5-FU was additive, that of concurrent 4OHT and Dox was less than additive in ER-alpha-positive cells. The increased expression of genes related to TAM resistance by Dox might be responsible for the interaction. Decreased TS activity by 4OHT might increase the antitumor activity of 5-FU. These findings may provide a preclinical rationale for concurrent use with 5-FU and TAM.

Epirubicin-cyclophosphamide adjuvant chemotherapy plus tamoxifen administered concurrently versus sequentially: randomized phase III trial in postmenopausal node-positive breast cancer patients. A GEICAM 9401 study

BACKGROUND

A prospective randomized clinical trial was implemented to assess whether the concomitant or the sequential addition of tamoxifen to chemotherapy provides improved clinical benefit in the adjuvant treatment of breast cancer in postmenopausal patients.

PATIENTS AND METHODS

Four-hundred and eighty-five patients with node-positive operable disease were randomized to receive tamoxifen (20 mg/day) concomitantly (CON) or sequentially (SEQ) to EC chemotherapy (epirubicin 75 mg/m(2) + cyclophosphamide 600 mg/m(2) on day 1, every 21 days for four cycles).

RESULTS

In the 474 fully evaluable patients there were 96 events; eight being second neoplasms and 88 being related to the breast cancer. Of these, 48 of 88 occurred in the CON arm and 40 of 88 in the SEQ arm. The Kaplan-Meier estimation of disease-free survival (DFS) at 5 years was 70% in the CON and 75% in the SEQ group (log-rank test, P = 0.43). Adjusted hazard ratio for treatment was 1.11 (95% confidence interval 0.71-1.73; P = 0.64).

CONCLUSION

This study fails to show an advantage of one treatment arm over the other, but a trend, albeit non-significant, appears to favor the sequential addition of tamoxifen to epirubicin + cyclophosphamide and, as such, warrants further investigation.

Effect of hormonal manipulation and doxorubicin administration on cell cycle kinetics of human breast cancer cells

Dual-parameter flow cytometry, following bromodeoxyuridine (BrdUrd) incorporation and propidium iodide (PI) uptake into DNA, was used to study the effects of oestradiol and/or insulin on cell cycle kinetics of human breast cancer cells in vitro. After a lag-period of 6-12 h, an optimum in the percentage of S-phase cells was reached between 18 and 24 h after hormone administration. A 1 h pulse of oestradiol was as effective as the continuous presence of oestradiol in pushing the cells from quiescent growing cultures into the cell cycle. A 1 h pulse of insulin was less effective than continuous administration. The addition of doxorubicin resulted in an accumulation of the cells in the late S/G2M-phases. It is concluded that dual-parameter flow cytometry allows accurate assessment of the effects of hormones and chemotherapy on the cell cycle. Therefore this method is very suitable for studying the interaction of hormones and chemotherapy on cell growth.

Diverse prognosis in metastatic breast cancer: who should be offered alternative initial therapies?

In an attempt to clarify appropriate treatment options for women with stage IV breast cancer, we studied the survival experience of a large dataset of patients treated on Cancer and Leukemia Group B (CALGB) protocols. The study, restricted to women who had had no prior chemotherapy for metastatic disease, demonstrated a surprisingly poor prognosis, with an estimated median survival of 1.6 years and only 26% alive at 3 years. Analysis of prognostic factors permitted the identification of subsets with even shorter survival, such as women with estrogen receptor negative tumor in more than one metastatic site and prior adjuvant chemotherapy. We feel that an evaluation of intensive investigational treatment approaches, such as trials using autologous bone marrow transplantation, is justified for most stage IV breast cancer patients, in view of their poor prognosis.

Rationale for combining chemotherapy and hormonal therapy in breast cancer

Both chemotherapeutic agents and hormones are effective in breast cancer treatment. Their mechanism of action seems to be conflicting: while cytotoxic drugs are active on cycling cells, hormones prolong the G0 phase. Therefore, the concurrent use of hormones and chemotherapy could decrease their expected clinical activity. On the contrary, a review of the literature suggests that there could be some synergistic action with combined therapy. The problem is therefore to assess the efficacy of simultaneous vs sequential administration of hormones and chemotherapy. In advanced disease the general conclusion could be that simultaneous administration of combined therapy: increases, although the difference is not statistically significant, the response rate both in pre and postmenopausal patients; and the most important end point, total survival, is not statistically improved by simultaneous vs sequential administration. In addition, in the adjuvant setting combined treatment appears superior to chemotherapy only in postmenopausal, receptor-positive patients. No definite conclusion is today available in premenopause.

Chemotherapy with cyclophosphamide, adriamycin, and 5-fluorouracil compared to chemotherapy plus hormonal therapy with tamoxifen in the treatment of advanced breast cancer: an interim analysis

Between February 1980 and August 1982, the Cancer and Leukemia Group B (CALGB) performed a randomized study aimed to compare chemotherapy with CAF (Cyclophosphamide, Adriamycin, 5-Fluorouracil) versus the same chemotherapeutic regimen plus tamoxifen (T-CAF) in stage IV breast cancer patients. Patients were stratified on the basis of menopausal status, estrogen receptors (ER) status, dominant site of metastasis and prior adjuvant treatment. Overall 474 patients were entered into the study of whom 433 were assessable for response. 314 patients were postmenopausal, 85 premenopausal and 34 patients were unknown as far menopausal status was concerned. No difference was evident among postmenopausal patients in overall response rate and duration of responses between T-CAF and CAF (52% vs 50% respectively). Similarly no difference was shown among premenopausal patients, response rates being 63% with T-CAF and 60% with CAF. Lack of benefit from adding T to chemotherapy was seen also according to the different strata, including patients with ER positive tumors. The failure for this combination to be synergistic might reflect an effect of T on tumor kinetics interfering with the activity of chemotherapy.

A randomized trial of chemotherapy and hormonal therapy in advanced breast cancer

We randomized 81 postmenopausal women with advanced breast cancer, whose tumors were rich in estrogen receptors or of unknown estrogen-receptor status, to receive either estrogen therapy alone or estrogen therapy combined with chemotherapy. An additional 31 patients, whose tumors were poor in estrogen receptors, were randomized to receive either chemotherapy alone or estrogen combined with chemotherapy. The median duration of follow-up was 87 months. In the receptor-rich group, the survival of the 21 patients receiving combined therapy was significantly longer than that of 19 patients receiving estrogen as initial therapy (followed by chemotherapy after failure or relapse). The median survivals were 72 and 29 months, respectively (P = 0.05 by the generalized Wilcoxon method). Among 41 patients with tumors of unknown receptor status, a survival advantage from combined therapy over chemotherapy was seen in the first two years and then disappeared. The survival in 31 patients with receptor-poor tumors was uniformly short regardless of the therapeutic method. We conclude that combined therapy offers a survival advantage in postmenopausal patients with receptor-rich tumors.

Combined cytotoxic and endocrine therapy in postmenopausal patients with advanced breast cancer. A randomized study of CMF vs CMF plus tamoxifen

In this study 263 patients with advanced measurable breast cancer were randomized to receive cyclophosphamide, methotrexate and 5-fluorouracil (CMF) or CMF + tamoxifen (T). Each cycle of CMF (C, 100 mg/m2 p.o. days 1-14, M 40 mg/m2 i.v. days 1 and 8, F, 600 mg/m2 i.v. days 1 and 8) was repeated every 4 weeks. Tamoxifen, 20 mg twice daily, was given continuously. The treatment results have been assessed by external review for the 220 evaluable patients and were the following for the CMF and CMF + T groups, respectively: PD: 24 and 10%; NC: 27 and 15%; PR: 29 and 44%; and CR: 20 and 31%. The difference between response (CR + PR) rates is highly significant (P = 0.0001). The median duration of remission was 12 months in the CMF-treated group and 18 months in patients treated with CMF + T (P = 0.09). The median duration of survival was 19 months and 24 months respectively (P = 0.07). However, in the group of responders patients receiving CMF + T survived significantly longer than those who received CMF alone (32 months vs 21 months, P = 0.005). The addition of T appeared to be of benefit in all subgroups. The largest differences were seen in patients with the dominant site of disease in the viscera, in patients with a Karnofsky index of 100, and in patients of more than 60 yr of age. The amount of CMF given was identical in the two treatment groups and there was a trend toward a decrease in dose with increasing age. No relationship between response and dose given was observed. In conclusion, the simultaneous use of T and CMF improves the therapeutic results in patients with advanced breast cancer.

Integration of hormonal agents and chemotherapy for the treatment of women with advanced breast cancer

Efforts have been made to improve the efficacy of combination chemotherapeutic regimens for advanced breast cancer by integrating additive hormonal agents. Results with respect to the value of such an approach are conflicting, and the routine use of chemohormonal therapy in clinical practice has not been established. Further work in this area is needed, especially in regard to the use of hormonal agents as manipulators of tumor cell kinetics to enhance the effectiveness of chemotherapy. In addition, clinical trials have compared the results of hormonal therapy alone with those of chemohormonal therapy; currently, the use of hormonal agents alone seems to be preferable for the initial treatment of most postmenopausal women with advanced breast cancer. The exception to this practice would be in those patients who are clinically not candidates for hormonal therapy because of the site, extent, or tempo of disease or because of the absence of hormonal receptors.

Chemoendocrine therapy vs chemotherapy alone for advanced breast cancer in postmenopausal women: preliminary report of a randomized study

From January 1980 to August 1982 the Cancer and Leukemia Group B conducted a prospective randomized trial comparing chemoendocrine therapy with T-CAF (cyclophosphamide, adriamycin, and 5-fluorouracil plus tamoxifen) to CAF alone in postmenopausal women with advanced breast cancer. The patients were stratified by estrogen receptor (ER) status into three groups: ER-negative, ER-positive, ER-unknown. They were also stratified by dominant site of metastatic disease: visceral and other (osseous and/or soft tissue). A total of 246 eligible patients were enrolled in the study; 232 were evaluable and constitute the basis for this report. The study revealed that there was no difference in overall response frequency or response duration between T-CAF and CAF; there was no difference in response between T-CAF and CAF in ER-positive or in ER-negative patients; and there was no difference in response between T-CAF and CAF by dominant site of metastatic disease. The expected advantage of T-CAF over CAF, especially for ER-positive patients, was not observed.

Efforts to combine endocrine and chemotherapy in the management of breast cancer: do two and two equal three?

Standard approaches to the systemic management of breast cancer have probably reached a plateau. Endocrine therapy leads to responses in only 1/3 of patients, probably even less if no clinical preselection is applied, and the median benefit probably does not exceed one year. Although three-drug chemotherapeutic combinations yield responses in 55-65% of patients, the median duration of response is at best only 10 months, and addition of more drugs does not seem to offer much additional benefit. Although combining these approaches seems attractive initially, the theoretical improvement would be modest even if the effects were additive, and in fact the endocrine component may well perturb the cell cycle kinetics to reduce sensitivity to the cytotoxic component so that results would be less than additive. Clinical trials of combined chemo-endocrine regimens have tended to evaluate only the initial response rate, whereas a valid comparison must consider the total response duration and survival given either combined or the usual sequential approaches. Combining endocrine and cytotoxic chemotherapies may have a greater effect when a more rational means for their amalgamation is employed. Early trials using endocrine manipulation to synchronize cell sensitivity to cytotoxic treatment have been promising. Increasing attention needs to be directed towards more innovative trial design which is respectful of the biological realities of cancer.