| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Department of Medical Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
S. Rodenhuis, M.D., Ph.D., The Netherlands Cancer Institute, Department of Medical Oncology, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands. Telephone: 31-20-512-2870; Fax: 31-20-512-2572; e-mail: sroden{at}nki.nl
| ABSTRACT |
|---|
|
|
|---|
Key Words. Breast cancer • High-dose chemotherapy • Adjuvant chemotherapy • Cyclophosphamide • Thiotepa • Carboplatin • Carmustine (BCNU) • Stem cell transplantation • Bone marrow transplantation
| INTRODUCTION |
|---|
|
|
|---|
The rationale of high-dose chemotherapy in breast cancer, the early studies and an analysis of the few available data from randomized studies have recently been reviewed by Peters et al. [4] in this journal. Rather than present a similar comprehensive overview, this paper will offer an interpretation of the available data from a slightly different perspective. In addition, the revelation that Dr. Bezwoda has falsified his results forces us to reevaluate the available information. The elimination of the randomized study of Bezwoda from our knowledge base actually simplifies this task, since it suggested a degree of (recurrence-free) survival benefit for high-dose therapy that was difficult to explain against the background of other randomized studies.
| HIGH-DOSE CHEMOTHERAPY AND THE CURE OF BREAST CANCER |
|---|
|
|
|---|
In high-risk primary breast cancer, recurrence-free survival is a reasonable but intermediate endpoint for randomized studies. As with any other form of adjuvant therapy, the objective is cure, but up to 20 years of follow-up would be required to ascertain that this goal has been achieved. Fortunately, long-term survival gain tends to accompany recurrence-free survival improvement in primary breast cancer [7].
| THE TOXICITY OF HIGH-DOSE CHEMOTHERAPY IN BREAST CANCER |
|---|
|
|
|---|
Acute toxicities commonly include nausea, vomiting, hair loss, mucositis, diarrhea, fatigue, and skin abnormalities. Severe organ toxicity is less frequent but may be life-threatening. In the randomized American Intergroup Study reported by Peters et al. [9], 7.4% of all transplanted patients died from toxicity. A major problem was a BCNU-induced pneumonitis that is absent in regimens not incorporating this drug. We have described a high frequency of veno-occlusive disease when multiple courses of a high-dose alkylating chemotherapy regimen are given [10]. The administration of oxazaphorines (cyclophosphamide or ifosfamide) as part of a high-dose regimen is associated with hemorrhagic cystitis, despite concomitant administration of mesna. Long-lasting or irreversible toxicity to sensory nerves and ototoxicity are characteristic for cisplatin and carboplatin-based regimens. Other chronic toxicities include infertility, premature menopause, chronic fatigue syndrome, and renal function impairment. We have recently reported that patients who received high-dose chemotherapy have significant neuropsychological sequelae, which may be irreversible [11]. Although these neuropsychological abnormalities are readily detectable by standard neuropsychological tests, their significance for the quality of life of patients and their ability to return to their prior work and lifestyle are uncertain at this point. Finally, high-dose therapy is associated with an increase in second malignancies, including myelodysplastic syndromes and leukemias [12], but probably also solid tumors.
| THE ABILITY OF HIGH-DOSE CHEMOTHERAPY TO INDUCE LONG-TERM SURVIVAL IN ADVANCED BREAST CANCER |
|---|
|
|
|---|
It is also quite obvious that the majority of patients undergoing high-dose therapy relapses and dies from disease. Several authors have reported on prognostic factors predicting survival after high-dose therapy [16, 17]. Most studies agree that the patients who are most likely to benefit from intensive chemotherapy are those with limited metastatic disease who are in good clinical condition and have tumors responsive to conventional-dose chemotherapy. This finding is remarkably consistent. For example, data from the European bone marrow registry indicate that patients who are transplanted in first complete remission from advanced breast cancer have a 35% disease-free survival for 3+ years [14]. A prospective, but unrandomized study performed by the Dutch Working Group on Autologous Transplantation in Solid Tumors indicated that patients in first complete remission following conventional-dose chemotherapy had a long-term disease-free survival of 43% [18]. These and many other reports essentially confirm the early study of Peters that showed that a single course of high-dose chemotherapy without any other treatment could achieve long-term disease-free survival in 3 of 22 patients with advanced breast cancer [19].
Based on all this evidence, there can be no doubt that high-dose chemotherapy induces long-term survival in a subgroup of patients. But the question remains if this subgroup is larger than that which achieves long-term disease-free survival after conventional-dose chemotherapy. The only randomized study addressing this is the recently reported study of Stadtmauer et al., frequently called the "Philadelphia study" [20]. Disappointingly, this study does not show a difference in disease-free survival between the patients randomized to the standard-dose arm and those randomized to high-dose arm. Also, the long-term disease-free survivals were identical: these were lower than 10%, for both the high-dose and conventional-dose groups. This is an important and discouraging result, and it strongly argues against the previously common practice of administering CTCb chemotherapy routinely several months after a response to conventional-dose chemotherapy. The results should, however, not be overinterpreted. The study had a number of important limitations:
These points of criticism certainly do not invalidate the findings of the Philadelphia study [20]. It is, however, conceivable that any benefit of high-dose therapy, even given as late intensification, could have been missed as a result of the study design.
Two other randomized studies of high-dose chemotherapy have been reported in stage IV breast cancer. The first was a study by Peters et al. [25]. This study indicated a relapse-free survival advantage for patients receiving high-dose therapy, but it compared early transplant to late transplant and therefore it does not directly provide information regarding the comparison between high-dose and conventional-dose therapy. Moreover, the overall survival was superior in the group that received delayed high-dose therapy. The second is a small French study, presented at the American Society of Clinical Oncology (ASCO) meeting in 1999 [26]. Sixty-one patients with stage IV breast cancer responding to conventional-dose chemotherapy were randomized to either receive two to four additional courses of conventional-dose chemotherapy, or to undergo high-dose chemotherapy with a regimen containing mitoxantrone 45 mg/m2, cyclophosphamide 120 mg/kg, and melphalan 140 mg/m2 (CMA). The study showed an insignificant trend for improved overall survival (p = 0.08) for the high-dose arm with an overall median survival of 36.1 versus 15.7 months.
In summary, the evidence from randomized studies is compatible with a modest gain in disease-free survival for high-dose chemotherapy, but this effect is far from proven. Because of this, randomized studies of high-dose chemotherapy in advanced breast cancer remain very important and several are in progress in North America and Europe. Unfortunately, it is quite likely that the recent negative publicity regarding high-dose therapy may adversely affect patient recruitment in these studies and many investigators may have lost interest.
| HIGH-DOSE CHEMOTHERAPY IN HIGH-RISK PRIMARY BREAST CANCER |
|---|
|
|
|---|
Unfortunately, it is uncertain at this point whether high-dose chemotherapy can add significantly to survival in advanced breast cancer, and the only information to go on in the adjuvant setting are the largely preliminary results of a few randomized studies. Only two trials with mature results are available. Both are negative, but both were small and had little statistical power [28, 29]. A number of large studies have been completed but all are still in the process of maturing.
The American Intergroup study has been reported in preliminary form by Peters [9]. A total of 783 patients who had received four courses of CAF as adjuvant chemotherapy for high-risk breast cancer were randomized to either receive the high-dose CPB regimen with PBPC transplantation or an intermediate dose of CPB that did not require PBPC transplantation. All patients subsequently received radiotherapy and tamoxifen if the primary tumor was positive for the estrogen receptor. At the median follow-up of 37 months, the event-free survival and overall survival comparisons between the high-dose and the intermediate-dose CPB patients were inconclusive (68% versus 64%, p = 0.7; and 78% versus 80%, respectively). There were, however, significantly fewer relapses in the high-dose group. Unfortunately, this benefit was offset by a high mortality in the high-dose group (7.4% of all patients transplanted). This high toxic death rate was mainly attributable to pulmonary toxicity of the CPB regimen, which contains 600 mg/m2 of carmustine.
The randomized study in high-risk breast cancer with the largest number of randomized patients is the study of the Dutch Working Group on Autotransplantation in Solid Tumors. This study, which closed in July of 1999, randomized a total of 885 patients. Roughly one-third of these patients had 10 or more tumor-positive axillary lymph nodes, the remainder of patients had four to nine positive axillary lymph nodes. Following definitive surgery, patients were randomized to receive either five courses of fluorouracil, epirubicin, and cyclophosphamide (FEC), followed by radiation therapy and tamoxifen, or to the same sequence in which the fifth course of FEC was replaced by high-dose chemotherapy with cyclophosphamide, thiotepa, and carboplatin. This high-dose regimen is similar to the CTCb (STAMP V) regimen, but it contains a double dose of carboplatin and the three alkylating agents are infused as short i.v. infusions rather than as continuous infusions [30]. This may lead to less inhibition of the activation route of cyclophosphamide than the continous infusion employed in the CTCb regimen [21, 22].
Preliminary survival results of this study have been reported at the ASCO meeting in 2000 [31]. At a median follow-up of 35 months, the three-year recurrence-free survival for the high-dose group was 72% versus 65% for the conventional-dose group (p = 0.057). A planned subgroup analysis of the first 284 patients in the study, who had a median follow-up of 53 months and a lead follow-up of almost seven years, showed recurrence-free and overall survival benefits that were both statistically significant. Clearly, these encouraging survival results of the Dutch study need further maturation, and a first meaningful statistical analysis is anticipated for the year 2002. At this point, however, it is also clear that the treatment mortality was only 1% in the high-dose arm compared to 7.4% in the American Intergroup study. The Dutch study was conducted in only 10 centers and probably included over 50% of the eligible patients in all of the Netherlands. It therefore approaches a population-based study. In addition, there was no crossover from the conventional-dose arm to the high-dose arm and there were fewer than 10% treatment refusals among patients randomized to the high-dose arm. Consequently, this study does not include a possible patient selection bias, and its results should answer the question whether late intensification is beneficial in the adjuvant treatment of high-risk breast cancer.
A number of other randomized studies are either ongoing or have recently been closed (Table 1
) from which no preliminary data have been released. Together with the studies described above, these should be able to provide a reliable answer by 2005.
|
| DEVELOPMENTS IN HIGH-DOSE CHEMOTHERAPY REGIMENS |
|---|
|
|
|---|
There are investigators who, based on data from uncontrolled studies and/or on conjectures and mathematical models, prefer certain approaches over others. Up front high-dose chemotherapy has been strongly advocated by some. Most of these investigators were encouraged by the apparently positive data of Bezwoda in both the adjuvant and advanced disease setting [1, 2], but now that these reports appear to be untrue, little empirical evidence for this approach remains.
Late intensification (high-dose therapy following conventional-dose induction therapy) continues to be a reasonable standard. The proof of concept that late intensification may improve treatment results has been delivered in other tumors, such as non-Hodgkin's lymphoma [32, 33]. In addition, conventional chemotherapy offers the additional benefit that it helps to identify a patient population that is more likely to derive long-term benefit from the high-dose part of chemotherapy [18].
Another matter of debate is whether repeated high-dose chemotherapy can best be given as high-dose alternating chemotherapy in which several different agents are used sequentially at their maximum dose [34, 35], or if repeated administration of the same high-dose regimen in a narrow time frame is preferable. We have advocated the latter approach, mainly because alternating chemotherapy has not been shown to have any clinical advantage in the conventional-dose setting [36, 37]. This line of reasoning appears to be justified, since it is difficult to see why different laws would govern the administration of high-dose versus conventional-dose chemotherapy.
A drawback of repeating the same type of high-dose chemotherapy, however, is the threat of severe end-organ toxicity. We have previously shown that three closely spaced cycles of high-dose cyclophosphamide, thiotepa, and carboplatin (CTC) lead to a high incidence of veno-occlusive disease, hemolytic uremic syndrome, and hemorrhagic cystitis [10]. More recently, we were able to demonstrate that three subsequent cycles of a somewhat lower dose of CTC are not associated with this excess toxicity [38, 39].
| THE SELECTION OF HIGH-DOSE CHEMOTHERAPY REGIMENS FOR BREAST CANCER |
|---|
|
|
|---|
It is reasonable to assume that high-dose chemotherapy should be added to effective conventional-dose therapy rather than substitute for it. For the cure of some breast cancers, dose-intensive therapy may be required. The eradication of other tumors may demand a high cumulative dose or, possibly, chemotherapy that is given over a very long period of time. Of course, any combination of these requirements may also be present in some tumors, and for other tumors none of these strategies may be effective. If this tumor characteristic is unknown, as is usually the case, the addition of high-dose therapy to conventional therapy (rather than the replacement of the former with the latter) affords the patient exposure to two strategies, either of which may be more beneficial for that individual's tumor. This could explain in part why both the Scandinavian study in high-risk breast cancer [40] and the Philadelphia study [20] in advanced breast cancer are negative. Both compare brief high-dose chemotherapy with prolonged and relatively dose-intensive conventional therapy. If certain tumors require either a high cumulative dose of chemotherapy or a long period of treatment, then these tumors will do better in the conventional arms. Only the tumors that are curable by a single exposure to very high concentrations of alkylating agents would be eradicated in the high-dose arms of these two studies. Such tumors appear to exist [19] but must be relatively infrequent.
The fact that we cannot classify breast cancer with similar characteristics and perform the studies in more homogenous patient categories leads to insensitive clinical trials and possibly to misleading interpretations. This situation may change dramatically in the next few years. Using micro-array mRNA expression profiling [41], we may for the first time be able to work out a sophisticated genetic classification of breast cancers, and this may help to design better clinical studies for sets of patients with well-characterized tumors [42].
| PROSPECTS |
|---|
|
|
|---|
| References |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
A. R. Zander, C. Schmoor, N. Kroger, W. Kruger, V. Mobus, N. Frickhofen, B. Metzner, W. E. Berdel, M. Koenigsmann, E. Thiel, et al. Randomized trial of high-dose adjuvant chemotherapy with autologous hematopoietic stem-cell support versus standard-dose chemotherapy in breast cancer patients with 10 or more positive lymph nodes: overall survival after 6 years of follow-up Ann. Onc., June 1, 2008; 19(6): 1082 - 1089. [Abstract] [Full Text] [PDF] |
||||
![]() |
A.R. Zander, N. Kroger, C. Schmoor, W. Kruger, V. Mobus, N. Frickhofen, B. Metzner, W. Schultze, W.E. Berdel, M. Koenigsmann, et al. High-Dose Chemotherapy With Autologous Hematopoietic Stem-Cell Support Compared With Standard-Dose Chemotherapy in Breast Cancer Patients With 10 or More Positive Lymph Nodes: First Results of a Randomized Trial J. Clin. Oncol., June 15, 2004; 22(12): 2273 - 2283. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Rodenhuis, M. Bontenbal, L. V.A.M. Beex, J. Wagstaff, D. J. Richel, M. A. Nooij, E. E. Voest, P. Hupperets, H. van Tinteren, H. L. Peterse, et al. High-Dose Chemotherapy with Hematopoietic Stem-Cell Rescue for High-Risk Breast Cancer N. Engl. J. Med., July 3, 2003; 349(1): 7 - 16. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Schneeweiss, M. Hensel, P. Sinn, T. Khbeis, R. Haas, G. Bastert, and A. D. Ho Characteristics associated with long-term progression-free survival following high-dose chemotherapy in metastatic breast cancer and influence of chemotherapy dose Ann. Onc., May 1, 2002; 13(5): 679 - 688. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. Cardinale, M. T. Sandri, A. Martinoni, E. Borghini, M. Civelli, G. Lamantia, S. Cinieri, G. Martinelli, C. Fiorentini, and C. M. Cipolla Myocardial injury revealed by plasma troponin I in breast cancer treated with high-dose chemotherapy Ann. Onc., May 1, 2002; 13(5): 710 - 715. [Abstract] [Full Text] [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| THE ONCOLOGIST | STEM CELLS | CME | ALPHAMED PRESS JOURNALS |