Cisplatin and VP16 in Metastatic Breast Carcinoma as a Third-Line Chemotherapy: A Randomized Study Comparing Low versus High Doses of Cisplatin

A Phase II Study of Paclitaxel/Cisplatin Combination in Patients with Metastatic Breast Cancer Refractory to Anthracycline-Based Chemotherapy

AIMS AND BACKGROUND

To investigate the safety and efficacy of a paclitaxel and cisplatin regimen in a selected group of metastatic breast cancer patients with primary or acquired chemo-resistance to anthracycline-based chemotherapy.

PATIENTS AND METHODS

Thirty-eight consecutive women with metastatic breast cancer (PS < or =2) were entered in this phase II trial; all patients had been previously treated for metastatic disease with chemotherapy containing anthracyclines and had shown a progression of the disease during drug administration or after a clinical response lasting less than 6 months. Fifteen patients had received 2 or more chemotherapeutic regimens for advanced disease; 31 patients had > or =2 sites of metastatic disease. Paclitaxel (135 mg/m2) was administered iv by a 3-hr infusion followed by iv infusion of cisplatin (75 mg/m2) on day 1, every 3 weeks for 6 cycles. After the completion of the planned chemotherapy administration, 9 responsive patients continued to receive paclitaxel alone (175 mg/m2) iv, on day 1, every 3 weeks, until disease progression or unacceptable toxicity.

RESULTS

A partial clinical response was recorded in 17 cases (45%; 95% CI, 30-64%). The median duration of overall response was 8 months; for the 9 responsive patients who continued treatment with paclitaxel alone, 4 had maintained the partial clinical response at the median follow-up of 24 months from the onset of therapy. The median time to progression was 6 months and median overall survival 8 months. Neurotoxicity was the most frequent adverse effect and caused treatment discontinuation in 5 cases for grade 3-4 paresthesia and/or an arthralgia/myalgia syndrome. Grade 3-4 neutropenia occurred in 16 patients (44%).

CONCLUSIONS

Paclitaxel/cisplatin is an active regimen for the treatment of patients with metastatic breast cancer refractory to anthracycline-based chemotherapy. However, the cumulative neurotoxicity should limit the efficacy of prolonged paclitaxel monotherapy in responsive patients.

Platinum-based compounds for the treatment of metastatic breast cancer

The role of platinum-based compounds (PBCs) in the treatment of metastatic breast cancer (MBC) has been extensively studied. As single agents, high response rates have been observed in first-line therapy, while results in pretreated patients were discouraging. Regimens containing cisplatin/carboplatin together with taxanes showed the highest efficacy and safety as both first-line and second-line therapy. When administered with vinorelbine, the combination was also active and well tolerated in anthracycline- and taxane-pretreated patients. Combining PBCs with etoposide or nucleoside analogues showed moderate activity, yet high toxicity in the case of etoposide. The overall results for the combination with anthracyclines were disappointing. Addition of trastuzumab to PBC combinations showed remarkable activity and good tolerability in patients with HER2/neu overexpression. The use of cisplatin or carboplatin alongside novel targeted therapeutics for patients with triple-negative MBC seems promising and is being further evaluated. The use of PBCs against MBC requires careful patient selection and combination with the right chemotherapeutic agent.

Platinum-based Chemotherapy in Metastatic Breast Cancer: The Leicester (UK) Experience

AIMS

After failure of anthracycline- and taxane-based chemotherapy in metastatic breast cancer, treatment options until recently were limited. Until the introduction of capecitabine and vinorelbine, no standard regimen was available. We conducted a retrospective study to determine the efficacy and toxicity of platinum-based chemotherapy in metastatic breast cancer.

MATERIALS AND METHODS

Forty-two women with metastatic breast cancer previously treated with anthracyclines (93%) and/or taxanes (36%) received mitomycin-vinblastine-cisplatin (MVP) (n=23), or cisplatin-etoposide (PE) (n=19), as first-, second- and third-line treatment at a tertiary referral centre between 1997 and 2002. Chemotherapy was given every 3 weeks as follows: mitomycin-C (8 mg/m2) (cycles 1, 2, 4, 6), vinblastine (6 mg/m2), and cisplatin (50 mg/m2) all on day 1; and cisplatin (75 mg/m2) and etoposide (100 mg/m ) on day 1 and (100 mg/m2) orally twice a day on days 2-3.

RESULTS

The response rate for 40 evaluable patients (MVP: n=23; PE: n=17) was 18% (95% confidence interval [CI]: 9-32%). The response rate to MVP was 13% (95% CI: 5-32%, one complete and two partial responses) and to PE 24% (10-47%, four partial responses). Disease stabilised in 43% (26-63%) and 47% (26-69%) of women treated with MVP and PE, respectively. After a median follow-up of 18 months, 37 women (MVP: n=19; PE: n=18) died from their disease. Median (range) progression-free survival and overall survival were 6 months (0.4-18.7) and 9.9 months (1.3-40.8), respectively. Median progression-free survival for the MVP and PE groups was 5.5 and 6.2 months (Log-rank, P = 0.82), and median overall survival was 10.2 and 9.4 months (Log-rank, P = 0.46), respectively. The main toxicity was myelosuppression. Grades 3-4 neutropenia was more common in women treated with PE than in women treated with MVP (74% vs 30%; P = 0.012), but the incidence of neutropenic sepsis, relative to the number of chemotherapy cycles, was low (7% overall). The toxicity-related hospitalisation rate was 1.2 admissions per six cycles of chemotherapy. No treatment-related deaths occurred. MVP and PE chemotherapy have modest activity and are safe in women with metastatic breast cancer.

Cisplatin plus oral etoposide (EoP) combination is more effective than paclitaxel in patients with advanced breast cancer pretreated with anthracyclines: a randomised phase III trial of Turkish Oncology Group

Our objective was to determine whether oral etoposide and cisplatin combination (EoP) is superior to paclitaxel in the treatment of advanced breast cancer (ABC) patients pretreated with anthracyclines. From December 1997 to August 2003, 201 patients were randomised, 100 to EoP and 101 to paclitaxel arms. Four patients in each arm were ineligible. The doses of etoposide and cisplatin were 50 mg p.o. twice a day for 7 days and 70 mg m⁻² intravenously (i.v.) on day 1, respectively, and it was 175 mg m⁻² on day 1 for paclitaxel. Both treatments were repeated every 3 weeks. A median of four cycles of study treatment was given in both arms. The response rate obtained in the EoP arm was significantly higher (36.3 vs 22.2%; P=0.038). Median response duration was longer for the EoP arm (7 vs 4 months) (P=0.132). Also, time to progression was significantly in favour of the EoP arm (5.5 vs 3.9 months; P=0.003). Median overall survival was again significantly longer in the EoP arm (14 vs 9.5 months; P=0.039). Toxicity profile of both groups was similar. Two patients in each arm were lost due to febrile neutropenia. The observed activity and acceptable toxicity of EoP endorses the employment of this combination in the treatment of ABC following anthracyclines.

Platinum-based chemotherapy in metastatic breast cancer: current status

Cisplatin and carboplatin are active in previously untreated patients with metastatic breast cancer (MBC) with mean response rates (RRs) of 50 and 32%, respectively. In pretreated patients the RR to cisplatin/carboplatin monotherapy declines markedly to <10%. Cisplatin and carboplatin have been combined with many other cytotoxics. In first-line setting high activity has been observed in combination with taxanes or vinorelbine (RRs consistently approximately 60%). It appears that these newer combinations are superior to older regimens with etoposide (RRs 30 to 50%) or 5-fluorouracil (RRs 40 to 60%). Cisplatin-/carboplatin-based regimens with infusional 5-FU and epirubicin/paclitaxel/vinorelbine achieve high RRs of around 60 to 80%. However these regimens are difficult to administer in all patients because they require central venous access for continuous 5-FU infusion. In pretreated MBC the combinations of cisplatin-taxane/vinorelbine/gemcitabine or carboplatin-docetaxel/vinorelbine yield RRs of 40 to 50%, which are higher than those achieved with platinum-etoposide/5-FU. In locally advanced disease cisplatin-based regimens achieve very high RRs (>80%). This would suggest that in chemotherapy-naïve patients platinum-based therapy might have an important role to play. Additionally the synergy demonstrated between platinum compounds, taxanes and herceptin, in preclinical and clinical studies is of immense importance and the results of the two ongoing Breast Cancer International Research Group randomized phase III studies are eagerly awaited. These studies may help clarify the role of platinum compounds in the treatment of metastatic and possibly early breast cancer.

Platinum compounds in the treatment of advanced breast cancer

Interest in platinum compounds for the treatment of breast cancer has been reawakened because of preclinical studies indicating synergy of platinum salts with the monoclonal antibody trastuzumab in human breast cancer cell lines that overexpress HER2/neu. Cisplatin, carboplatin, and iproplatin are not very active as single agents in patients with previously treated metastatic breast cancer (MBC). The activity of oxaliplatin has not been adequately tested in refractory MBC. On the other hand, cisplatin is very active as first-line chemotherapy, with response rates (RR) of 50%; carboplatin appears to be moderately active in patients without prior chemotherapy (RR around 30%). The clinical effectiveness of the other platinum compounds (iproplatin, oxaliplatin, and others) has not yet been fully tested as first-line chemotherapy. Platinum compounds have been extensively tested in combination with other antitumoral agents. Cisplatin combinations have been employed as neoadjuvant chemotherapy in women with locally advanced breast cancer. These combinations are very active, although the precise contribution of cisplatin to the overall activity is not known. Combinations with cisplatin have been investigated, essentially, as salvage therapy for patients with previously treated MBC. The combinations of cisplatin with older pharmacological agents (5-fluorouracil, etoposide) have moderate activity, while the combinations of cisplatin with the newer agents (vinorelbine, paclitaxel, docetaxel, gemcitabine) appear to be more active. The combinations of carboplatin with the classical agents (5-fluorouracil, etoposide) are poorly active in previously treated MBC; however, the combination of carboplatin with the taxanes (docetaxel, paclitaxel) is more active. Of greatest interest is the synergy between the platinum derivatives and the monoclonal antibody trastuzumab demonstrated in vitro in breast cancer cell lines overexpressing HER2/neu. Currently, several combinations of platinum compounds (either cisplatin or carboplatin) with docetaxel and trastuzumab are under clinical testing in patients with MBC who overexpress HER2/neu. The preliminary results are very promising, and these combinations will soon be tested in the adjuvant setting. Cisplatin, carboplatin, and perhaps, oxaliplatin appear to have some antitumor activity in MBC and can be combined safely with other agents that are active in this disease. However, the precise role that platinum compounds play in the treatment of breast cancer remains to be defined.

Systematic reviews of chemotherapy and endocrine therapy in metastatic breast cancer

Metastatic breast cancer is incurable but often responsive to treatment. There is little evidence-based consenus on when to use which treatments, in what combination and for how long. Systematic reviews were performed on 12 prospectively defined, clinically relevant research questions to support the development of evidence-based clinical practice guidelines. A comprehensive search of Medline from 1966 to 1996 identified over 1800 controlled trials. Eligibility and data extraction were performed independently by two blinded reviewers. Trial results were summarised by ratios of median survivals (RMS) and P -values for survival curve comparisons with meta-analysis by weighted combination of these statistics. Sixty-five publications reporting 97 treatment comparisons were included. There was moderate evidence that more rather than fewer cycles of chemotherapy improved survival (RMS:1.23, P -0.01). The evidence did not support: higher rather than lower doses of chemotherapy (or of endocrine therapy); any one class of endocrine agent over all others; multiple endocrine agents over a single agent; or, combined chemotherapy and endocrine therapy over either single modality. Only six trials assessed quality of life revealing better quality of life with more rather than fewer cycles of chemotherapy and with standard rather than lower doses of chemotherapy. These systematic reviews reveal counterintuitive evidence useful to everyday practice, in particular that more rather than fewer cycles of chemotherapy lead to better quality of life and longer survival.

Is there a role for intensive therapy in breast cancer?

With reference to survival, polychemotherapy has been demonstrated to be statistically significantly more effective than monochemotherapy both in the adjuvant setting and in the metastatic situation. Breast cancer demonstrates a dose-response relationship. Chemotherapy used in the conventional dose range should be given with adequate dose-intensity both in the adjuvant setting and for metastatic patients. More dose-intensive combinations are almost always associated with a higher response rate in patients' metastatic disease, but these results have seldom been translated into an improved survival. For marrow requiring high-dose therapy, repeated phase II studies have demonstrated the possibility of a survival tail, which may be due to stage migration and patient selection. At present we have at least 13 ongoing phase III studies in the adjuvant setting and at least 5 ongoing studies in the metastatic situation. These studies will give a definite answer on whether marrow-supported high-dose therapy is better than conventional therapy or if alternative approaches using tailored therapy will result in an equivalent outcome. In the future we must make better use of the present arsenal of drugs and examine the marked inter-individual variations in pharmacokinetic profiles for the drugs. We have to tailor the therapy to the tumour biological profile, in both the primary tumour and metastases with appreciation of heterogeneity and tumour progression. Based on these prerequisites, therapy can be either dose-intensive or in some instances continuous using lower doses.

Brain metastases in breast cancer: prognostic factors and management

In this retrospective study, 162 breast cancer patients were analysed in whom brain metastases had been diagnosed clinically between 1969 and 1995 at a single institution. 145 patients were treated with megavoltage irradiation (60 cobalt or 6MV) of the whole brain using opposed fields. The most common applied schedule consisted of 30 Gy in 15 daily fractions over 3 weeks. 10 patients underwent surgery and 17 patients received symptomatic treatment only. The median age was 50 years (range 30-78 years). 81 of 162 patients (50%) were premenopausal. Women younger than 40 years of age had a shorter survival (median 12 weeks) than those of all other groups (median 29 weeks). Median survival was 82 weeks for the 10 surgical patients, 26 weeks for the 145 patients treated with radiotherapy and 5 weeks for the patients who received symptomatic (corticosteroid) therapy only. Patients with solitary metastases treated with radiation alone (45 patients) had a survival of 44 weeks versus 23 weeks in patients with multiple brain metastases. Multivariate stepwise regression analyses revealed Karnofsky Index, dose of radiation (P < 0.001), solitary metastases (P < 0.04) and primary tumour size (P < 0.04) as significant prognostic factors for survival.