One-day VATH (vinblastine, Adriamycin, thiotepa, and Halotestin) therapy for advanced breast cancer refractory to chemotherapy

High Dose Thiotepa in Patients with Relapsed or Refractory Osteosarcomas: Experience of the SFCE Group

Introduction. Osteosarcoma relapse has a poor prognosis, with less than 25% survival at 5 years. We describe the experience of the French Society of Paediatric Oncology (SFCE) with high dose (HD) thiotepa and autologous stem cell transplantation (ASCT) in 45 children with relapsed osteosarcoma. Patients and Methods. Between 1992 and 2004, 53 patients received HD thiotepa (900 mg/m²) followed by ASCT in 6 centres. Eight patients were excluded from analysis, and we retrospectively reviewed the clinical radiological and anatomopathological patterns of the 45 remaining patients. Results. Sixteen girls and 29 boys (median age, 15.9 years) received HD thiotepa after initial progression of metastatic disease (2), first relapse (26), and second or third relapse (17). We report 12 radiological partial responses and 9 of 31 histological complete responses. Thirty-two patients experienced further relapses, and 13 continued in complete remission after surgical resection of the residual disease. Three-year overall survival was 40%, and 3-year progression-free survival was 24%. Delay of relapse (+/− 2 years from diagnosis) was a prognostic factor (P = 0.011). No acute toxic serious adverse event occurred. Conclusion. The use of HD thiotepa and ASCT is feasible in patients with relapsed osteosarcoma. A randomized study for recurrent osteosarcoma between standard salvage chemotherapy and high dose thiotepa with stem cell rescue is ongoing.

Phase III Study of Standard Combination Versus Rotating Regimen of Induction Chemotherapy in Patients With Hormone Insensitive Metastatic Breast Cancer

OBJECTIVE

The objective of this multicenter phase III trial was to study the impact on time to treatment failure (TTF) and survival of cyclophosphamide, Adriamycin, and 5-fluorouracil (CAF) versus CAF/thiotepa, Adriamycin, vinblastine, and Halotestin (TsAVbH), a partially noncross-resistant regimen used in a rotating schedule in the treatment of hormone insensitive metastatic breast cancer in accordance with the Goldie and Coldman hypothesis.

METHODS

Three hundred forty-three patients received 6 cycles of induction treatment with one of 2 regimens. Patients with estrogen receptor-negative tumors or those with estrogen receptor-positive or estrogen receptor-unknown tumors with demonstrated unresponsiveness to hormone treatment were eligible. Complete responders were randomized to either observation or maintenance therapy with cyclophosphamide, methotrexate, 5-fluorouracil, prednisone, tamoxifen, and Halotestin (CMF[P]TH). Patients with partial response or stable disease on completion of induction therapy were maintained on CMF plus Halotestin.

RESULTS

There were no differences in the primary end point of TTF (median 7.3 and 7.4 months, respectively). There was a significant difference in TTF and survival by duration of disease-free interval: a median of 8.8 and 21.2 months for those with a disease-free interval of > or =2 years versus 6 to 8 and 13.3 months for those with a disease-free interval <2 years (P = 0.016 and <0.001), respectively. Toxicity of the 2 treatment regimens was similar.

CONCLUSION

There were no differences observed in TTF, survival, and toxicities between the 2 treatment arms, both of which contained doxorubicin (Adriamycin) as the most active agent. The results of observation versus maintenance in complete responders were reported separately.

The genetic basis of resistance to cancer chemotherapy

The Goldie-Coldman hypothesis of how tumours develop resistance to chemotherapy predicts that random mutations occur within a tumour cell population that bestows cytotoxic resistance. These resistance mechanisms may be specific to a certain class of cytotoxic drug, such as changes the enzymes topoisomerase II and dihydrofolate reductase, or may affect many drugs simultaneously, such as increased expression of P-glycoprotein. Knowledge of the genetic basis of these resistance mechanisms will have fundamental clinical importance in individual cases by allowing cytotoxic regimes that are unaffected to be chosen. Moreover, it will allow the development of more effective modulators of resistance.

A phase II study of thioTEPA in children with recurrent solid tumor malignancies: a Children's Cancer Group study

A Phase II study of thioTEPA was performed by the Children's Cancer Group. ThioTEPA was administered intravenously every three weeks, at a dose of 65 mg/m2. Pediatric patients with recurrent sarcomas were targeted, but patients with other tumor diagnoses were also eligible. Toxicity was primarily hematopoietic, with thrombocytopenia being predominant. ThioTEPA did not demonstrate significant activity in the target tumor groups evaluated.

Lymphoblastoid interferon in advanced breast cancer: a phase II study

Thirty-two metastatic breast cancer patients entered a phase II study in order to evaluate the toxicity and the clinical activity of lymphoblastoid interferon (IFN). The treatment was divided into two phases, induction and maintenance. During the first, patients were submitted to lymphoblastoid IFN at the dose of 3 MU die intramuscularly for 4-8 weeks; during maintenance treatment IFN was given at the same dosage, intramuscularly, every other day until progression. Five patients with inadequate follow-up were excluded from disease evaluation, thus 27 patients were evaluable for response. No complete response was observed; one patient achieved a partial response and 15 patients disease stabilization. Median time to progression in patients with partial response or stable disease was 11 weeks (range 2-32). Five patients with soft tissue metastases were biopsied before and after 1-2 months of treatment in order to perform Labelling Index and hormonal receptor status determinations. No significant modification was observed.

An intensive sequenced adjuvant chemotherapy regimen for breast cancer

Twenty-two women (17 pre- and 5 postmenopausal) with nodepositive, stage II breast carcinoma were treated with adjuvant chemotherapy consisting of 16 weeks of intensive CMFVP (cyclophosphamide, methotrexate, 5-fluorouracil, vincristine, and prednisone) administered in the original dose and schedule of the "Cooper regimen," followed by four monthly, 3-day cycles of escalating doxorubicin. Toxicity was related primarily to myelosuppression associated with the doxorubicin component of the treatment regimen. All patients recovered without sequelae. No patient developed significant cardiac toxicity. With a median follow-up of 43 months (range: 20-89 months), two postmenopausal patients and one premenopausal patient have relapsed at 35, 37, and 42 months, respectively. By Kaplan-Meier survival analysis, there is an 80.5% chance of disease-free survival to 42 months. The feasibility of administering adjuvant CMFVP followed by intensive doxorubicin has been established. The pilot results warrant comparative trial with the best of current regimens.

Managing breast cancer in an outpatient setting

The treatment of advanced breast cancer has undergone relatively little change in the past decade. Reasons for such a static situation are the sobering realization that even effective chemotherapeutic regimens have had a minor impact on survival, and the paucity of new effective agents that have been introduced since initial combination treatments. Based in part on this lack of progress, in recent years dose-intensification in search of a curative strategy has been widely adopted. Its role remains to be defined, but ultimately it is likely to be relegated to situations where tumor burdens have been effectively reduced. This reduction in burden may not currently be feasible in many advanced presentations. Outpatient efforts will therefore focus on the following: 1) employing single agents optimally (e.g. infusion 5-fluorouracil), 2) using regimens which integrate new drugs with activity (e.g. taxol), and 3) testing measures which may improve the quality of life (e.g. bisphosphonates in the presence of bone metastases). Although one cannot approach the treatment of advanced breast cancer with the (misplaced) optimism of two decades ago, the expanded armamentarium currently available should lead to a more rational application of chemotherapy. Treatments will increasingly be based on the biology of the cancer, and on the therapeutic index and action of the drugs.

The clinical pharmacology and use of antimicrotubule agents in cancer chemotherapeutics

Although there has been a rapid expansion of the number of classes of compounds with antineoplastic activity, few have played a more vital role in the curative and palliative treatment of cancers than the antimicrotubule agents. Although the vinca alkaloids have been the only subclass of antimicrotubule agents that have had broad experimental and clinical applications in oncologic therapeutics over the last several decades, the taxanes, led by the prototypic agent taxol, are emerging as another very active class of antimicrotubule agents. After briefly reviewing the mechanisms of antineoplastic action and resistance, this article comprehensively reviews the clinical pharmacology, therapeutic applications, and clinical toxicities of selected antimicrotubule agents.

Comprehensive management of disseminated breast cancer

The management of patients with metastatic breast cancer is best achieved by the judicious use of local and systemic measures that palliate symptoms and improve overall quality of life. When two treatment approaches are known to be equally efficacious, the less toxic should be used. When disease is limited to one or two sites and the patient has an indolent form of the disease, the patient's symptoms are often best palliated with the use of surgery or radiotherapy alone. When multiple sites of disease are evident or the disease is progressing more rapidly, systemic therapy is preferred, and local therapies should be added when the patient is clearly refractory to systemic therapy or when the disease site is unlikely to be adequately palliated with systemic therapy. The use of any of these therapies, including chemotherapy, has a relatively small effect on the median survival of patients with metastatic breast cancer. However, improvements in quality of life are usually greatest with regimens inducing the highest response rates, even when these regimens are associated with greater toxicity. The characteristics of patients likely to respond to endocrine therapy are well defined; in these patients endocrine therapy should be used as the first form of systemic therapy. Among endocrine therapies, the least toxic is used first. The selection of patients for chemotherapy is largely a process of exclusion. When chemotherapy is used, there are a number of different strategies for sequencing chemotherapy that appear to be equally efficacious. In general, patients should be treated with standard doses of drug combinations for a period in excess of 3 months. When used inappropriately, especially in asymptomatic patients, these therapies may actually compromise the patient's quality of life. The use of surgery, radiation therapy, and systemic therapy should be integrated with various types of psychosupport services, especially peer support groups. Patients who want to try new forms of therapy should do so early in the course of the disease when these therapies are most likely to be effective and the patient has the least to lose if the therapy proves ineffective. This is especially true because the use of the most effective regimens at a time when the patient is asymptomatic may mean that the patient is resistant to most or all therapies of proven value when most in need of palliation.

A phase I clinical trial of intraperitoneal thiotepa for refractory ovarian cancer

Treatment options for patients with ovarian cancer who have failed systemic and intraperitoneal (ip) cisplatin-based chemotherapy are limited. We conducted a phase I clinical study of ip thiotepa in patients with refractory ovarian cancer to determine the maximum tolerated dose (MTD). Ten patients were given 39 courses of thiotepa (median number of courses per patient, 3.5; range, 1-10+). All patients had received prior ip cisplatin; 7 also had received iv cisplatin, and 5 had three or more prior regimens. Thiotepa (30-80 mg/m2) was given ip in 2 liters normal saline every 4 weeks. The therapy was well tolerated. There was no vomiting, stomatitis, alopecia, or peritonitis. The dose-limiting toxicity was myelosuppression. With repeated doses, patients had a delayed marrow recovery and required a 1- to 2-week delay in treatment. Six patients had stable disease (duration 2-14+ months; median duration 5 months); 1 patient had a 50% decrease in CA-125 level, and 1 patient with no measurable disease remained clinically disease-free. In summary, ip thiotepa had clinical activity in heavily pretreated patients with refractory ovarian cancer with disease stabilization seen in 6 of 9 evaluable patients and a partial response seen in 1 patient. Myelosuppression was the only toxicity encountered. A dose of 60 mg/m2 ip is recommended for phase II studies.

Combination chemotherapy of advanced breast cancer. Comparison of dibromodulcitol, doxorubicin, vincristine, and fluoxymesterone to thiotepa, doxorubicin, vinblastine, and fluoxymesterone: an Eastern Cooperative Oncology Group Study

Two Adriamycin (doxorubicin)-based chemotherapy regimens were investigated in patients with carcinoma of the breast who had failed prior systemic therapy. The two chemotherapy programs, dibromodulcitol, Adriamycin, vincristine, and Halotestin (fluoxymesterone) (DAVH), and thiotepa, Adriamycin, vinblastine, and Halotestin (TAVH), were chosen for comparison on the basis of reported response rates of 40% to 50% with remission durations of 11 months in patients refractory to other cytotoxic chemotherapy. Cycles of DAVH were repeated every 4 weeks. Cycles of TAVH were repeated every 3 weeks. Of 184 patients evaluable for response, 32% of patients treated with DAVH and 38% of patients treated with TAVH had a complete response (CR) or partial response (PR). An additional 5% of patients had nonmeasurable improvement in osseous disease for an overall rate of response (CR + PR + improvement) of 40%. Patients who had previously received cytotoxic chemotherapy for metastatic disease or had early failure after adjuvant therapy had a lower response rate to DAVH, but not to TAVH than those who did not fail prior chemotherapy. Duration of response and survival were similar with the two treatments. There were seven treatment-related deaths, five among patients receiving DAVH and two among patients receiving TAVH. Patients receiving DAVH had significantly more thrombocytopenia and neurologic toxicity than those receiving TAVH. These treatments appear to be reasonable second-line regimens and are good candidates to be used in initial therapy of metastatic disease or adjuvant therapy studies that explore the use of alternating non-cross-resistant combinations with cyclophosphamide, methotrexate, and 5-fluorouracil.

Cellular pharmacology of N,N',N''-triethylene thiophosphoramide

N,N',N''-triethylene thiophosphoramide (Thio-TEPA) is an alkylating agent whose antineoplastic activity has been known for nearly 30 years. Human plasma pharmacokinetic studies revealed the presence of TEPA, a Thio-TEPA metabolite which after 4 h achieved plasma concentrations equal to those of the parent compound. We studied the activity of both Thio-TEPA and TEPA against murine leukemia P388 cells in culture. We found that Thio-TEPA is approximately two-fold more active than TEPA in arresting cell growth (IC50 = 2.8 microM for TEPA and 1.5 microM for Thio-TEPA). In inhibiting [3H]thymidine incorporation, Thio-TEPA and TEPA have the same activity (IC50 = 2 microM for both compounds). Experiments in which drug was removed from cell cultures which were further incubated in drug-free media, revealed that the bulk of the cell damage occurs during the first 4 h of incubation. Cell cultures exposed to 0.5 microM Thio-TEPA for 22 h fully recovered their [3H]thymidine incorporation ability after 24 h of drug-free incubation. Cells exposed to 2.5 microM Thio-TEPA for 22 h partially recovered their ability to incorporate [3H]thymidine. Cells exposed to 10 microM Thio-TEPA for 22 h did not recover their ability to incorporate [3H]thymidine. Gas liquid chromatographic analysis of the media from incubated cells showed that the concentration of Thio-TEPA remained unchanged during the incubations and that TEPA was not present. In Thio-TEPA doses ranging from 0.1 microM to 100 microM, [3H]uridine and [3H]-leucine incorporation were less affected than [3H]thymidine incorporation. This may indicate that a longer observation time may be needed to allow the DNA damage to be expressed in terms of protein or RNA synthesis.

Adriamycin, vinblastine and mitomycin C as second-line chemotherapy in advanced breast cancer

Thirty-six evaluable patients with metastatic measurable breast carcinoma previously treated with CMF or CMFVP were given second-line chemotherapy with Adriamycin, vinblastine, and mitomycin C (AVM), as follows: Adriamycin 20 mg/m2 and vinblastine 6 mg/m2 by i. v. push on days 1, 8, and 15, and mitomycin C 10 mg/m2 i. v. on day 1, every 6 weeks. Ten patients (28%) achieved partial remission (PR) lasting a median of 10 months, and eight patients (22%) experienced improvement of a lesser level than PR. An additional nine patients (25%) had disease stabilization; in the remaining nine patients (25%), persistent disease progression was observed. The median survival from the onset of AVM was 7 months for all patients; patients with PR survived a median of 13 months. Myelotoxicity was substantial and frequently interfered with the optimal administration of AVM, especially in patients with skeletal metastases; four patients were hospitalized with leukopenia and fever; all recovered promptly; one death was probably related to thrombocytopenia and CNS bleeding. Our results with AVM are similar to the average response rate published in the literature with the use of Adriamycin as a single agent in previously treated patients with advanced breast cancer.

In the search for new anticancer drugs. XV. Various aliphatic and aromatic hydrazones containing the N,N;N',N'-bis(1,2-ethanediyl)phosphoric diamide moiety

The scope of the structure-anticancer activity relationship among various aliphatic and aromatic hydrazones containing the N,N,N',N'-bis(1,2-ethanediyl)-phosphoric diamide moiety was studied. A total of 19 compounds were tested in vivo, using murine lymphocytic leukemia P388. At optimum dose all these compounds were active. The highest activity was exhibited by the N,N;N',N'-bis(1,2-ethanediyl)-[N2-(p-chlorobenzylidene)-N1- hydrazin-1-yl]phosphoric triamide, N,N;N',N'-bis(1,2-ethanediyl)-N2-(p-chlorobenzylidene)-N1- methylhydrazin-1-yl]phosphoric triamide and N,N;N',N'-bis(1,2-ethanediyl)-[N2-(p-chlorobenzylidene)-N1- phenylhydrazin-1-yl]phosphoric triamide as is evidenced by the percent T/C of 212, 194 and 192, respectively. An attempt was made to correlate the anticancer activities with the corresponding lipophilicities. On the basis of the activity-lipophilicity results, it is concluded that, in general, the activity scale follows the lipophilicity scale in the reverse order, i.e. the more active compounds possess lower lipophilicity than the less active compounds.

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.

Adriamycin, dibromodulcitol, and mitomycin combination chemotherapy for patients with metastatic breast carcinoma previously treated with cyclophosphamide, methotrexate, 5-fluorouracil, vincristine, and prednisone

Twenty-six evaluable patients with metastatic breast carcinoma previously treated with a combination of cyclophosphamide, methotrexate, 5-fluorouracil, vincristine, and prednisone (CMFVP) were treated with a combination of doxorubicin (Adriamycin), dibromodulcitol, and mitomycin (ADM). Four patients (15%) achieved complete remission, and 10 patients (39%) had a partial response. Five patients (19%) had stable disease, and seven patients (27%) experienced disease progression. The median time to disease progression was 10 months for responding patients (range, 4-44 months) and 5 months (range, 2-13 months) for patients with stable disease. The median survival duration was 15 months (range, 6-44+ months) for responders, 11 months (range, 2-27 months) for patients with stable disease, and 4 months (range, 2-41 months) for nonresponders. Two of the four patients with complete remission are alive and in continued remission at a follow-up of 44 and 40 months. Seventy-one patients with greater than or equal to two sites of metastasis responded, whereas 23% of patients with greater than or equal to three metastatic sites responded. Although higher responses were seen with soft tissue and osseous metastasis, responses were observed in all three sites of metastasis. This combination chemotherapy regimen with ADM is an effective second-line program for patients who have previously received CMFVP chemotherapy.

Vincristine, doxorubicin and mitomycin (VAM) in patients with advanced breast cancer previously treated with cyclophosphamide, methotrexate and fluorouracil (CMF). A clinical trial of the Piedmont Oncology Association (POA)

Thirty-six evaluable patients with advanced breast cancer who had failed prior CMF therapy [15 (42%) as adjuvant treatment and 21 (58%) for advanced disease] were treated with a combination of vincristine, doxorubicin, and mitomycin (VAM). There was one CR and 10 PR, giving a response rate of 31% (P, 95% confidence interval, 15%-47%). Response was not significantly related to age, performance status, disease-free interval, dominant site of disease, number of sites of disease, or estrogen receptor status. The median duration of response was 5 months for patients attaining CR or PR and 4.6 months for patients with stable disease. The median survival for patients with CR or PR of 7.9 months was not better than for those with stable disease (8.0 months), but both groups had significantly longer survival than those with initial progression. Patients who received VAM after failing adjuvant CMF had a 53% response rate (8 of 15), as against a 14% response rate (3 of 21) in those failing CMF for advanced disease (P less than 0.05). In spite of this difference, the survival distributions for these two groups were not significantly different. Myelosuppression was moderate and no cardiac toxicity was seen. The addition of mitomycin to vincristine and doxorubicin in previously treated patients does not appear to improve the results obtained with vincristine and doxorubicin alone.

5-Fluorouracil + Oncovin + Adriamycin + mitomycin C (FOAM): an effective program for breast cancer, even for disease refractory to previous chemotherapy. A Northern California Oncology Group (NCOG) Study

One hundred and thirty-one patients (118 evaluable) with disseminated breast cancer were treated with a combination of 5-fluorouracil + Oncovin + Adriamycin + mitomycin C (FOAM). The objective response rate for 82 evaluable patients whose disease was refractory to previous CMF or L-PAM chemotherapy was 35%; that for 36 evaluable patients who had not previously received chemotherapy, 56%. The hematologic toxicity of this therapy was generally mild and acceptable. It is believed that FOAM is an effective therapy for patients whose tumors are resistant to CMF.

Chemotherapy of breast cancer: current views and results

The paper critically reviews major accomplishments achieved with the use of chemotherapy in the treatment of various stages of breast cancer. In spite of innumerable clinical trials, there is no evidence that in advanced breast cancer the addition of more drugs, either in concomitant, sequential or alternating fashion, to known effective combinations, was able to significantly improve the incidence and the magnitude of objective response or its median duration or survival. The addition of endocrine therapy to chemotherapy has failed so far to improve the most important end-point, i.e. total survival. Second-line chemotherapy is only moderately effective for a fairly short period of time. Thus, in women with advanced breast cancer excessive tumor cell burden and permanent drug resistance remain the major obstacles to obtaining complete remission and long-term disease free survival. In the adjuvant setting, the initial trials with combination chemotherapy have achieved consistent results, particularly in women with minimal axillary node involvement. Unless a woman has undergone a surgical breast-saving procedure, postoperative radiotherapy does not appear to play an important therapeutic role, either with or without concomitant or sequential chemotherapy. Present results would suggest that in advanced breast cancer little progress can be expected in the near future. Therefore, medical oncologists should focus on the correct application of established drug regimens, using a sequential flow of hormonal manipulations and cytotoxic chemotherapy. In high-risk groups, full dose adjuvant polydrug therapy given for a relatively short period of time appears to be at present the only means able to significantly decrease the failure rate following local regional treatment. Present consistent achievements, which appear devoid of important delay morbidity (e.g. cancerogenesis, chronic organ damage) will require further clinical research to identify more effective and less toxic treatments.

Vincristine, adriamycin, and mitomycin (VAM) therapy for previously treated breast cancer. A preliminary report

Fifteen patients with metastatic breast cancer previously treated with chemotherapy were treated with a regimen consisting of vincristine, Adriamycin, and mitomycin. Eleven patients (73%) responded with three complete and eight partial responses. The median duration of response was eight months. While all four nonresponders died within five months, the median duration of survival of responders was 18 months. Toxicity was significant but tolerable. Thus, this preliminary report suggests that this regimen is active in advanced previously treated breast cancer, providing meaningful remissions with acceptable toxicity.

Adjuvant therapy of breast cancer 1971-1981. Ten years of progress

Adjuvant therapy in the past 10 years has gone from experimental to clinical practice for women who are premenopausal. For the postmenopausal and the elderly patient the treatment for some is still experimental and for others proven. Obviously, we need to collect data for all patients because we do not have information on 10 or 20 year survivals, the long-term effects of chemotherapy, or the role of adjuvant hormonal therapy. Likewise further trials are needed to define the optimal duration of treatment, the role of adriamycin combinations, and the utility of chemotherapy in node negative patients. Future trials will undoubtedly include lesser surgery options. The hope of the future lies in the definition of more specific options for treatment, avoiding the unnecessary toxicity of radical surgery, extensive X-ray therapy or needless chemotherapy. These answers will come from well-designed clinical trials, well-integrated with good laboratory studies designed to explore biological as well as mechanistic questions.