Chemotherapy of advanced breast cancer: a randomized trial of vincristine, Adriamycin, and cyclophosphamide (VAC) versus cyclophosphamide, methotrexate, 5-fluorouracil, and prednisone (CMFP)

Ifosfamide - History, efficacy, toxicity and encephalopathy

In this review we trace the passage of fundamental ideas through 20^th century cancer research that began with observations on mustard gas toxicity in World War I. The transmutation of these ideas across scientific and national boundaries, was channeled from chemical carcinogenesis labs in London via Yale and Chicago, then ultimately to the pharmaceutical industry in Bielefeld, Germany. These first efforts to checkmate cancer with chemicals led eventually to the creation of one of the most successful groups of cancer chemotherapeutic drugs, the oxazaphosphorines, first cyclophosphamide (CP) in 1958 and soon thereafter its isomer ifosfamide (IFO). The giant contributions of Professor Sir Alexander Haddow, Dr. Alfred Z. Gilman & Dr. Louis S. Goodman, Dr. George Gomori and Dr. Norbert Brock step by step led to this breakthrough in cancer chemotherapy. A developing understanding of the metabolic disposition of ifosfamide directed efforts to ameliorate its side-effects, in particular, ifosfamide-induced encephalopathy (IIE). This has resulted in several candidates for the encephalopathic metabolite, including 2-chloroacetaldehyde, 2-chloroacetic acid, acrolein, 3-hydroxypropionic acid and S-carboxymethyl-L-cysteine. The pros and cons for each of these, together with other IFO metabolites, are discussed in detail. It is concluded that IFO produces encephalopathy in susceptible patients, but CP does not, by a "perfect storm," involving all of these five metabolites. Methylene blue (MB) administration appears to be generally effective in the prevention and treatment of IIE, in all probability by the inhibition of monoamine oxidase in brain potentiating serotonin levels that modulate the effects of IFO on GABAergic and glutamatergic systems. This review represents the authors' analysis of a large body of published research.

Sequential versus Alternating Regimens in the Treatment of Advanced Breast Cancer

With the object of proving whether seqeuntial or alternate forms of chemotherapy would be advantageous one over the other in treating advanced breast cancer and with the purpose of evaluating two different anthracyclines at equimolecular doses in the above-mentioned alternating regimens, 250 patients who had received no prior chemo- or hormonotherapy were entered in a prospective randomized trial. Group A was administered 4-epiadriamycin and cyclophosphamide for 8 courses, followed by 6 cycles of CMF, and medroxyprogesterone acetate (MPA) from the beginning of therapy until progression. In group B, adriamycin + cyclophosphamide were alternated with CMF every two courses until 14 cycles were completed. Group C received 4'-epiadriamycin + cyclophosphamide alternated with CMF for 14 courses. In groups B and C, MPA was administered as in group A. Two hundred and twenty-four patients were evaluated. CR+PR were observed in 55.8 % of group A, 43.4 % of group B, and 46.4 % of group C. Median duration of responses was 16 months (m) in group A, 13 m in group B and 20 m in group C., and median survival (CR + PR) was 16.5 m in group A, 16 m in group B and 24 m in group C. There were no statsitically significant differences among the three groups in terms of response rate, duration of response and survival; furthermore, toxicity was moderate in all groups. At equimolecular doses there were no differences between adriamycin and epirubicin in the alternating schedules.

Antitumour antibiotic containing regimens for metastatic breast cancer

BACKGROUND

Antitumour antibiotics are used in the management of metastatic breast cancer. Some of these agents have demonstrated higher tumour response rates than non-antitumour antibiotic regimens, however a survival benefit has not been established in this setting.

OBJECTIVES

To identify and review the randomised evidence comparing anti-tumour antibiotic containing chemotherapy regimens with regimens not containing an anti-tumour antibiotic in the management of women with metastatic breast cancer.

SEARCH STRATEGY

The specialised register maintained by the Editorial Base of the Cochrane Breast Cancer Group was searched on 2nd May, 2003 using the codes for "advanced breast cancer" and "chemotherapy". Details of the search strategy and coding applied by the Group to create the register are described in the Group's module on The Cochrane Library.

SELECTION CRITERIA

Randomised trials comparing anti-tumour antibiotic containing regimens with regimens not containing anti-tumour antibiotics in women with metastatic breast cancer.

DATA COLLECTION AND ANALYSIS

Data were collected from published trials. Studies were assessed for eligibility and quality, and data were extracted by two independent reviewers. Hazard ratios (HRs) were derived from time-to-event outcomes where possible, and a fixed effect model was used for meta-analysis. Response rates were analysed as dichotomous variables. Quality of life and toxicity data were extracted where present. A primary analysis was conducted for all trials and by class of antitumour antibiotic.

MAIN RESULTS

Thirty-three trials reporting on 45 treatment comparisons were identified. All trials published results for tumour response and 26 trials published time-to-event data for overall survival. The observed 4084 deaths in 5284 randomised women did not demonstrate a statistically significant difference in survival between regimens that contained antitumour antibiotics and those that did not (HR 0.97, 95% CI 0.91 to 1.03, P = 0.35) and no significant heterogeneity. Antitumour antibiotic regimens were favourably associated with time-to-progression (HR 0.84, 95% CI 0.77 to 0.91) and tumour response rates (odds ratio (OR) 1.34, 95% CI 1.21 to 1.48) although statistically significant heterogeneity was observed for these outcomes. These associations were consistent when the analysis was restricted to the 29 trials that reported on anthracyclines. Patients receiving anthracycline-containing regimens were also more likely to experience toxic events compared to patients receiving non-antitumour antibiotic regimens. No statistically significant difference was observed in any outcome between mitoxantrone-containing and non-antitumour antibiotic-containing regimens.

REVIEWERS' CONCLUSIONS

Compared to regimens without antitumour antibiotics, regimens that contained these agents showed a statistically significant advantage for tumour response and time to progression in women with metastatic breast cancer but were not associated with an improvement in overall survival. The favourable effect on tumour response and time to progression observed in anthracycline-containing regimens was also associated with greater toxicity.

Does a drug do better when it is new?

BACKGROUND

When assessing a new, promising therapeutic approach, a clinician's perception of a drug's effectiveness may be shaped by different kinds of phenomena, and among them, a favorable attitude towards new treatments, and as a result a tendency to overestimate their efficacy (wish bias).

MATERIALS AND METHODS

A retrospective study of published randomized clinical trials of doxorubicin-based chemotherapy for advanced breast cancer was carried out. Global (complete plus partial) response rate over time with allowance for type of drug regimen (mono- or polychemotherapy) and prior adjuvant therapies was assessed in the doxorubicin-containing arm using multivariate logistic regression analysis.

RESULTS

Twenty-nine studies published from 1975 to 1999 were retrieved for a total of 2234 women with advanced breast cancer enrolled in the doxorubicin-containing arms. There was a significant decrease in response rate to doxorubicin as first-line treatment over time that resisted adjustment for important differences in therapeutic management [odds ratio for global response = 0.89, 95% confidence interval (CI) 0.81 to 0.99].

CONCLUSIONS

Although only one drug (doxorubicin) in one clinical context (advanced breast cancer) has been analyzed, our findings support the use of double blind methodology whenever possible when assessing subjective endpoints and encourage further studies aimed at defining the clinical relevance of a wish bias in medicine.

Sensitization to doxorubicin resistance in breast cancer cell lines by tamoxifen and megestrol acetate

Acquired drug resistance is a major factor in the failure of doxorubicin-based chemotherapy in breast cancer. We determined the ability of megestrol acetate and/or tamoxifen to reverse doxorubicin drug resistance in a doxorubicin-resistant breast cancer line (the human MCF-7/ADR). The cytotoxicity of doxorubicin, megestrol acetate, and/or tamoxifen was determined in the sensitive and resistant cell lines utilizing the sulphorhodamine B assay. Tamoxifen alone produced an IC50 (concentration resulting in 50% inhibition of control growth) of 10.6 microM, whereas megestrol acetate alone resulted in an IC50 of 48.7 microM in the MCF-7/ADR cell line. The IC50 of doxorubicin in MCF-7/ADR was 1.9 microM. Neither megestrol acetate alone nor tamoxifen alone at 1 or 5 microM altered the IC50 of doxorubicin. However, the combination of tamoxifen (1 or 5 microM) and megestrol acetate (1 or 5 microM) synergistically sensitized MCF-7/ADR cells. Additionally, megestrol acetate and tamoxifen inhibited iodoarylazidoprazosin binding to P-glycoprotein, and, in their presence, there was an increased doxorubicin accumulation in the MCF-7/ADR cells. Furthermore, the combination of tamoxifen and megestrol acetate had much less effect on the cytotoxicity of doxorubicin in MCF-7 wild-type cells. Clinically achievable concentrations of tamoxifen and megestrol acetate can largely sensitize MCF-7/ADR to doxorubicin. The combination of these three drugs in a clinical trial may be informative.

Phase II study of oral menogaril as first line chemotherapy for advanced breast cancer: a National Cancer Institute of Canada Clinical Trials Group study

The National Cancer Institute of Canada (NCIC) Clinical Trials Group conducted a phase II study of weekly oral menogaril as first-line therapy in 51 patients with incurable, metastatic or locally advanced breast cancer. While no prior chemotherapy for metastatic disease was permitted, prior adjuvant chemotherapy was allowed provided that no anthracycline or anthracene had been given. Forty-eight patients were evaluable for response. Two patients (4%) achieved complete remissions, 9 patients (19%) achieved partial remissions, 26 patients (54%) were stable and 11 patients (23%) failed. At the initial menogaril dose of 275 mg/m2 per week, 13 of 14 patients required a dose reduction and/or a treatment delay of one or more weeks. Therefore, the menogaril dose was reduced to 225 mg/m2 per week for the last 37 patients. At that those, 20 of 37 patients developed grade 3 or 4 granulocytopenia and 22 required dosage delays. At the initial starting dose, the average dose intensity actually delivered was 169 mg/m2 per week. At 225 mg/m2 the average dose intensity actually delivered was 197 mg/m2 per week. Toxic effects included mild to moderate nausea and vomiting, diarrhea, hair loss and occasional hyperpigmentation. In summary, menogaril is an anthracycline derivative that has modest activity when administered orally to minimally pretreated patients with breast cancer.

Long-term survival of patients treated with combination chemotherapy for metastatic breast cancer

Long-term survival of patients with metastatic breast cancer treated on two prospective stratified randomised trials has been analysed. Patients on study B122 received either cyclophosphamide, methotrexate and 5-fluorouracil (CMF) or cyclophosphamide, doxorubicin and 5-fluorouracil (CAF). On study B141 patients received CAF or mitolactol (dibromodulcitol), doxorubicin and vincristine alternating after every three cycles with three cycles of CMF (DAV/CMF). Long-term follow-up of 172 patients showed no significant survival difference (in multivariate regression models) for treatment with either CMF vs. CAF or CAF vs. DAV/CMF. The difference in median survival times between CMF and CAF showed a trend in favour of CAF. Advances in the management of metastatic breast cancer in postmenopausal women obtained by doxorubicin regimens have had a small but measurable impact on survival, but known patient discriminants were not overridden by the treatment regimens investigated in these studies.

Mitomycin C and mitoxantrone chemotherapy for advanced breast cancer: efficacy with minimal gastrointestinal toxicity and alopecia

In an attempt to examine the possibility of decreased toxicity in patients with advanced breast cancer who had not previously received chemotherapy, 33 women were given combination chemotherapy consisting of mitomycin C (10 mg/m2) every 6 weeks and mitoxantrone (6 mg/m2) every 3 weeks. The patients had predominantly visceral disease and received a median of two cycles of therapy. Of the 32 evaluable subjects, 15 (47%) achieved a partial response lasting a median of 7 months. Hematological toxicity was generally mild, although there were two episodes of sepsis. One patient developed hemolytic-uremic syndrome, and one subject developed pulmonary fibrosis, both presumably attributable to treatment with mitomycin C. Another patient died of hepatic failure (hepar lobatum). Thus, there were five patients who sustained life-threatening toxicities; this may have been due to the poor performance status and advanced age of some of the patients. Gastrointestinal toxicity and alopecia were minimal. Patient acceptance was high and there was an improvement in symptomatology in the majority of patients. In conclusion, mitomycin C and mitoxantrone chemotherapy is an active drug combination for the treatment of advanced breast cancer that seldom causes significant distressing gastrointestinal side effects or alopecia; however, the duration of response to this regimen appears to be shorter than that obtained with either cyclophosphamide - methotrexate - 5-fluorouracil (CMF) or cyclophosphamide - Adriamycin - 5-fluorouracil (CAF) combination chemotherapy.

Primary chemotherapy with mitoxantrone and prednisone in advanced breast carcinoma. A phase II study

Thirty-seven evaluable patients with progressive disseminated breast carcinoma were treated with a combination of mitoxantrone 14 mg/m2 i.v. every 3 weeks plus prednisone 20 mg/m2 p.o. daily with a reducing dose over several weeks. Thirteen of 37 patients (35%) achieved an objective response with two complete regressions. The median duration of response was 7 months and the median duration of survival 14 months. The cardiac function of all patients was monitored by serial left ventricular ejection fraction, at rest and after stress, and 3-monthly thereafter. Ten patients showed a deterioration in the ejection fraction after a minimum cumulative dose of 86 mg/m2 (six cycles), but only four developed clinical cardiac failure which was easily reversible after stopping mitoxantrone. Leucopenia was the dose-limiting toxicity. Nausea and/or vomiting were generally mild and transient. Alopecia was minimal. These results confirmed that this combination is effective and well tolerated in the treatment of disseminated breast carcinoma, and cardiotoxicity can be avoided with adequate monitoring of the left ventricular ejection fraction after six cycles of therapy (86 mg/m2).

Hormono-chemotherapy in the treatment of advanced breast cancer

The current situation in the treatment of metastatic breast cancer is reviewed. Overall the concurrent use of endocrine treatment and chemotherapy does not improve the therapeutic results as compared to a treatment encompassing only one modality. However, results diverge widely in different subgroups. Data emerging from various randomized trials are beginning to define subgroups of patients, who should be treated differently. Such data are discussed and their importance for future trials in the field of advanced breast cancer reviewed.

Chemotherapy of breast cancer

Carcinoma of the breast will prove fatal to over 37,000 women in the United States in 1983, despite attempts at early diagnosis. Hormonal manipulation, known to provide effective palliation for many years, can now be effectively aimed at receptor positive women who have a 50-70% chance of responding. Newer agents, such as tamoxifen and aminoglutethimide offer the benefits of older treatments with less morbidity. Investigations of drugs acting at the level of the central nervous system are ongoing. Single agent chemotherapy is clearly effective in causing tumor regression, but effective combination chemotherapy provides more responses and a longer duration of response. The most effective combination regimens at present contain doxorubicin. Pharmacologic studies at the cellular level can be expected to provide more effective combinations. The most effective way to combine hormonal and chemotherapeutic treatments is not known. In receptor positive women without life-threatening disease, beginning with hormonal treatment may be effective in providing palliation at low toxic cost without jeopardizing overall survival. New efforts to cure clinically manifest metastatic breast cancer may eschew palliation as a prime goal. Techniques of synchronizing and of stimulating breast cancer to increase its susceptibility to cytotoxic drugs are under investigation. Immunotherapy is not established as a beneficial modality in the treatment of breast cancer, although levamisole has led to suggestive benefit in small controlled trials. The use of chemotherapy, and possibly of some hormonal treatments in appropriate patients, as an adjuvant to surgery prolongs disease-free survival. This approach, using established chemotherapeutic and hormonal agents when the metastatic disease is subclinical, is consonant with abundant evidence from experimental systems and other human cancers that are curable. Expectation of curing human breast cancer will likely require aggressive action at the time when the total body tumor burden is at a minimum.

Doxorubicin and CCNU with or without vincristine in patients with advanced refractory breast cancer. A randomized trial

Thirty-five patients with advanced breast cancer refractory to initial chemotherapy were randomized to receive two-drug doxorubicin-CCNU or three-drug doxorubicin-CCNU-vincristine (VCR) treatment. Doxorubicin (25-40 mg/m2) and VCR (1.4 mg/m2) were given intravenously every 21 days; CCNU (65-90 mg/m2) was given orally every 42 days. Patients with liver or bone marrow metastases initially received the lower range doses. All patients failed prior chemotherapy with cyclophosphamide and 5-FU with or without methotrexate and prednisone; 67% received prior hormonal therapy. Pretreatment patient characteristics were comparable in both groups. Objective responses (greater than 50% reduction in tumor size) were seen in 7 of 18 patients (39%) on the VCR containing arm and in 8 of 17 patients (46%) on the doxorubicin-CCNU arm. Survival was not improved by VCR addition with overall survival on the doxorubicin-CCNU arm, approximately 10% greater at all intervals (median 9.1 versus 7.0 months; not statistically significant). However, neurotoxicity was significantly greater in the VCR arm (36% versus 0%; P less than 0.05). In advanced breast cancer, no benefit to VCR addition was seen in prior randomized studies of first-line combinations where VCR was the treatment variable. Such results, combined with our experience with VCR in a salvage regimen, question the value of VCR addition to combination regimens in advanced breast cancer.