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© 1999 American Society for Clinical Oncology Long-Term Survival in Metastatic Transitional-Cell Carcinoma and Prognostic Factors Predicting Outcome of TherapyFrom the Genitourinary Oncology Service, Division of Solid Tumor Oncology, Department of Medicine, Division of Urology, Department of Surgery, and Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, and Department of Medicine, Cornell University Medical College, New York, NY. Address reprint requests to Dean F. Bajorin, MD, Memorial Sloan-Kettering Cancer Center, 1275 York Ave, New York, NY 10021.
PURPOSE: The variation in reported survival of patients with metastatic transitional-cell carcinoma (TCC) treated with systemic chemotherapy may be a consequence of pretreatment patient characteristics. We hypothesized that a prognostic factorbased model of survival among patients treated with methotrexate, vinblastine, doxorubicin, and cisplatin chemotherapy could account for such differences and help guide clinical trial design and interpretation. PATIENTS AND METHODS: A database of 203 patients with unresectable or metastatic TCC was retrospectively subjected to a multivariate regression analysis to determine which patient characteristics had independent prognostic significance for survival. Patients were assigned to three risk categories depending on the number of unfavorable characteristics. Patient selection in phase II studies was addressed by developing a table of expected median survival for patient cohorts that had varying proportions of patients from the three risk categories. RESULTS: Two factors had independent prognosis: Karnofsky performance status (KPS) less than 80% and visceral (lung, liver, or bone) metastasis. Median survival times for patients who had zero, one, or two risk factors were 33, 13.4, and 9.3 months, respectively (P = .0001). The median survival time of patient cohorts could vary from 9 to 26 months simply by altering the proportion of patients from different risk categories. CONCLUSION: The presence of baseline KPS less than 80% or visceral metastasis has an impact on survival. Reporting the proportion of patients with zero, one, and two risk factors will facilitate understanding of the relevance of the median survival in phase II trials. Phase III trials should stratify patients according to the number of risk factors to avoid imbalance in treatment arms.
THE ACTIVITY OF THE four-drug regimen of methotrexate, vinblastine, doxorubicin, and cisplatin (M-VAC) in transitional-cell carcinoma (TCC) of the urothelial tract is well documented. The initial trial with this combination at Memorial Sloan-Kettering Cancer Center (MSKCC) reported a 72% major response proportion, including 36% of patients rendered disease-free by chemotherapy alone or chemotherapy in combination with postchemotherapy surgery.1 In two subsequent phase III trials, an improvement in both the response proportion and survival was demonstrated for M-VAC relative to single-agent cisplatin and the three-drug regimen of cisplatin, doxorubicin, and cyclophosphamide.2,3 On the basis of these data, M-VAC represents one standard of care for patients with unresectable or metastatic TCC. However, the median survival of patients treated with M-VAC approximates 1 year, and long-term survival occurs in only a small proportion of patients.4 Recent efforts to improve the outcome of patients with metastatic TCC have focused on the identification of novel drugs with single-agent activity and on their incorporation into platinum-based combination regimens. Paclitaxel, docetaxel, ifosfamide, and gemcitabine are among the most active of the newly identified agents for TCC.5-9 A large number of phase I and II trials have evaluated these agents in two- and three-drug combination regimens.10-18 Despite similarities in some of these regimens, there is marked variation in outcome. The response proportions observed with these combinations vary considerably, and median survival times range from 8 to 18 months.10,11,18 In contrast, median survival for the M-VAC combination is consistently observed at 11 to 13 months.1-3 Conceivably, the reported efficacy of these new regimens is affected by the pretreatment prognostic features of the treated populations. Because the prevalence of prognostic features may profoundly affect trial outcome, a thorough understanding of these data in a trial population is essential. Pretreatment prognostic features have an impact on individual patient outcome. Similarly, the prevalence of prognostic features within a treatment population has an impact on trial results. Several analyses have demonstrated that pretreatment prognostic features affect the outcome of patients treated with M-VAC chemotherapy for metastatic TCC.2,4,19 The prognostic factors found to be most predictive of poor response and survival are bone or liver metastases (determined either by radiographic abnormality or by an elevated baseline alkaline phosphatase level) and poor performance status. The intergroup study by Loehrer et al2 reported a median survival of 18.2 months for patients with the most favorable combination of prognostic features, compared with only 4.4 months for patients with the least favorable combination. The impact of prognostic features on survival was further emphasized in a long-term follow-up report from the intergroup trial in which none of the patients with liver or bone metastasis and only one patient with Karnofsky performance status (KPS) less than 80% survived for 6 years.4 It is conceivable that the distribution of prognostic factors within a trial population may affect the response and survival characteristics of a phase II cohort of patients. A therapy that has a certain inherent efficacy could result in a more favorable outcome when applied to a cohort of patients with more favorable prognostic features and less efficacy in patients with unfavorable prognostic characteristics. Despite the data showing that pretreatment characteristics affect individual patient outcome, no methodology exists that standardizes these prognostic factors or estimates their impact on the reported survival of new combination chemotherapy in clinical trials. Therefore, modeling survival based on the prevalence of pretreatment prognostic features in a population of patients treated with standard therapy might facilitate comparison of the efficacy of differing regimens. We hypothesized that a prognostic factorbased model of survival among patients treated with M-VAC could be used to assess the efficacy of novel treatment regimens relative to that observed with M-VAC therapy. Development of this model required several steps. First, to determine which patient characteristics had independent prognostic significance, a Cox proportional hazards model was fit using data from a population of 203 patients with unresectable or metastatic TCC treated on five consecutive trials of M-VAC chemotherapy. Second, the choice of the variables and the parameter estimates were validated internally by generating data using a bootstrap resampling technique. Finally, a table with expected median survival for cohorts of patients who had a varying prevalence of prognostic features was tabulated.
Patient Population Two hundred twenty-nine patients were treated on five trials of M-VAC chemotherapy at our institution between 1983 and 1994 (Table 1). One hundred thirty-three patients were treated in our original trial examining the efficacy of standard-dose M-VAC chemotherapy.1 Twenty-seven patients were treated in a trial examining the utility of recombinant human granulocyte colony-stimulating factor (rhG-CSF) in combination with standard-dose M-VAC.20 Twenty-nine patients were enrolled onto a phase II trial testing methotrexate 1,000 mg/m2 and leucovorin rescue with standard-dose VAC.21 Twenty-three patients were enrolled in a phase I/II trial examining the feasibility of dose-intense M-VAC using rhG-CSF support.22 Finally, 17 patients in a phase II randomized trial comparing dose-intense M-VAC plus rhG-CSF with gallium nitrate plus fluorouracil received M-VAC as initial therapy.23 Of these 229 patients, 26 were excluded from the current analysis: three had urothelial tumors of non-TCC histologic origin, four were treated in an adjuvant setting, and 19 had clinical tumor-node-metastasis stages T3bN0 and were treated in the neoadjuvant setting. The remaining 203 patients, with unresectable or metastatic TCC, form the basis of this report.
Inclusion criteria for the five studies were similar. Histologic confirmation of TCC was performed at MSKCC in all cases. Patients with known brain metastasis were excluded from all studies. Adequate renal, hepatic, and cardiac function was required in all cases. In the first study, low KPS was not an exclusion criteria, whereas patients who had KPS less than 60% were excluded from the other four trials. All trials were approved by the institutional review board at MSKCC, and informed consent was given by all patients. Twelve of the 203 patients in our database had received prior systemic treatment. Agents included methotrexate (12 patients), vinblastine (six patients), and cisplatin (three patients). All pretreated patients in our database were enrolled onto the first of the five trials, which was the only one that allowed pretreatment. Patients received a median of four cycles (range, 1 to 12 cycles) of M-VAC. Response was assessed by re-evaluation of known sites of disease by physical examination, cystoscopy, and radiography after every two cycles of therapy or as clinically indicated. After achieving a maximum response to chemotherapy, selected patients were referred for postchemotherapy surgery for resection of residual carcinoma and assessment of pathologic response.
Survival Analysis
Survival distributions were estimated using the Kaplan-Meier method.24 The relationship between survival and each of the variables was analyzed, using the log-rank test for categorical variables and a score test based on the Cox proportional hazards model for continuous variables. This model equates the relative risk of survival with the exponential of a constant times the covariate of interest:
Validation of the Survival Model by Bootstrap Technique
Expected Median Survival Tabulation The expected median survival for patients who had varying distributions of prognostic factors and who were treated with M-VAC was tabulated to address the issue of better patient selection in phase II studies. The bootstrap resampling technique was used to generate samples with a varying prevalence of prognostic factors. Let a, b, and c equal the percentage of patients with zero, one, and two risk factors, respectively, so that a + b + c = 100. For a sample size N, a, b, and c% of patients were drawn with replacement from the three corresponding risk categories in the M-VAC database, and the median survival was estimated using the Kaplan-Meier method. The process was repeated 300 times to generate an empirical distribution of median survival for a given a, b, and c. The median of this distribution provided an overall median survival adjusted for patient selection, and the 95% confidence interval was chosen as the 2.5th and 97.5th percentile of this distribution. The table was created by repeating this process for all possible combinations of a, b, and c between 10% and 90% with increments of 10%.
Patient Characteristics The distribution of pretreatment clinical characteristics for the 203 patients is shown in Table 2 . The median age at initiation of therapy was 63 years (range, 23 to 83 years), and 80% of patients were male. KPS was available for 199 patients; the median KPS for the entire cohort was 80%, and 41% of patients had a KPS of less than 80%. The primary tumor site was the bladder in 79% of patients, the renal pelvis in 10%, and the ureter or urethra each in 5%. Visceral metastases were relatively prevalent in the cohort, with 49% of patients having lung, liver, or bone disease.
Response to Chemotherapy and Survival Distribution The median survival time for the entire cohort of 203 patients was 14.8 months (95% confidence interval, 12.1 to 16.2 months) at a median follow-up of 40 months (Fig 1). The 5-year survival rate was 17%, and at the time of this analysis, 19 (9%) of the 203 patients were alive.
Univariate Survival Analysis
Only three of 100 patients with visceral metastasis were alive at the time of the analysis, including two of 53 patients with lung metastasis, one of 52 with bone metastasis, and zero of 26 with liver metastasis (Table 3). Among patients without visceral metastasis, 16 of 103 remained alive. Only two of 81 patients with KPS less than 80% were alive at the time of this analysis, compared with 17 of 118 patients with a baseline KPS of
Multivariate Survival Analysis
Internal Validation
Risk Groups
The impact of risk factors on likelihood of response to chemotherapy was also examined. The proportion of patients who obtained a major response to chemotherapy was 78%, 74%, and 36% among patients with zero, one, and two risk factors, respectively. Similarly, 35% of patients who had zero risk factors, 11% of patients with one risk factor, and 0% of patients with two risk factors attained a complete response.
Expected Median Survival Table Interpretation
This analysis establishes performance status and visceral metastatic sites of disease as independent prognostic factors for predicting survival in patients with metastatic TCC. The impact of low performance status has previously been reported in analyses of phase II studies from our center as well as from the intergroup randomized trial of M-VAC versus cisplatin.2,19 The presence of visceral disease has also demonstrated prognostic significance in previous analyses, although the specific measure of visceral disease has varied. The presence of lung, liver, or bone metastasis was of independent significance in the current analysis and in the initial intergroup report.2 In a long-term follow-up of the intergroup study patients, only liver and bone metastasis retained prognostic significance.4 A previous analysis from our institution did not specifically analyze the prognostic impact of visceral metastasis but did determine that elevated alkaline phosphatase, an indirect measure of visceral metastasis to bone or liver, was prognostically important.19 Thus, lower KPS and the presence of visceral metastases are patient characteristics consistently demonstrated to have independent prognostic significance for survival in patients with metastatic TCC. A simple model of the impact of prognostic factors on survival was developed which emphasizes the profound survival impact of poor performance status and visceral sites of metastasis. Patients who had no risk factors fared best, with a median survival time of 33.0 months, compared with 13.4 months for patients with one risk factor and 9.3 months for those with two risk factors. Because performance status and baseline visceral metastasis have independent prognostic significance, reporting these patient characteristics in studies examining novel chemotherapy regimens would enhance trial interpretation. For example, a trial of a new regimen reporting a high response proportion and enhanced survival may simply reflect the inclusion of a high proportion of patients with zero or one risk factor. An imbalance of prognostic factors may also affect the outcome of phase III trials. For these reasons, we propose that the proportion of patients with zero, one, and two risk factors should be included in phase II trials and that phase III trials should be stratified accordingly. The availability of new agents with activity in TCC, such as paclitaxel and gemcitabine, has led to a large number of novel regimens.10-18 Results obtained in trials of these combinations vary substantially in the reported response rates and survival, making trial interpretation difficult. For example, median survival times for taxane-containing regimens range from 8.5 months to 18 months,10,11,18 and the differences may not be related to the chemotherapy regimens. Therefore, choosing a regimen for phase III study based solely on enhanced survival may be problematic if the phase II study enlisted a large proportion of good-risk patients. We sought to address this issue by developing a nomogram of expected median survival times of M-VACtreated patients based on hypothetical proportions of patients in each risk category for a typical phase II trial. The goal of this exercise was to produce a table enabling informal comparison of survival data from phase II trials of novel combinations in the context of known prognostic factors. The table was developed using bootstrap resampling technique and Kaplan-Meier methodology. It facilitates comparison of the relative efficacy of M-VAC in phase II studies at our center with novel treatmentregimens in phase II study, on the basis of the prevalence of prognostic factors in the treated populations. Median survivals for cohorts of patients who have a predefined prevalence of risk factors treated with M-VAC are provided. By knowing the distribution of risk factors in a clinical trial, the reader can assess the relative efficacy of a new agent or regimen. This approach facilitates phase II study interpretation and phase III trial design. It reduces the likelihood of a false interpretation of a regimen studied in a poor-risk population showing a relatively lower median survival compared with another study with more favorable results based on inclusion of patients with more favorable risk factors. The model makes it convenient to select chemotherapy regimens for phase III study. Promising regimens can be chosen for a randomized trial if the reported median survival of the phase II trial population is longer than that expected for conventional therapy for a patient population with similar risk factors. Although the survival model has been internally validated, its predictive accuracy still needs to be corroborated with an external data set of similarly treated patients. Moreover, median survivals are predicted based on treatment with conventional M-VAC in the 1980s and early 1990s. It is possible that improvements in therapy, including the introduction of new, active agents used in the second- and third-line setting, may prolong survival in contemporary patients. In summary, we report a cumulative 17% 5-year survival rate from M-VAC studies in our center. Pretreatment prognostic factors significantly affect survival. Patients with a poor KPS and evidence of visceral disease did not experience long-term survival, in contrast to a 33% likelihood of 5-year survival in patients with none of these poor risk features. Lastly, these factors can be used to predict survival and aid in the interpretation and conduct of phase II and III trials.
1. Sternberg CN, Yagoda A, Scher HI, et al: Methotrexate, vinblastine, doxorubicin, and cisplatin for advanced transitional cell carcinoma of the urothelium. Cancer64:2448-2458, 1989[Medline] 2. Loehrer PJ Sr, Einhorn LH, Elson PJ, et al: A randomized comparison of cisplatin alone or in combination with methotrexate, vinblastine, and doxorubicin in patients with metastatic urothelial carcinoma: A cooperative group study. J Clin Oncol10:1066-1073, 1992[Abstract] 3. Logothetis CJ, Dexeus FH, Finn L, et al: A prospective randomized trial comparing MVAC and CISCA chemotherapy for patients with metastatic urothelial tumors. J Clin Oncol8:1050-1055, 1990[Abstract]
4.
Saxman SB, Propert KJ, Einhorn LH, et al: Long-term follow-up of a phase III intergroup study of cisplatin alone or in combination with methotrexate, vinblastine, and doxorubicin in patients with metastatic urothelial carcinoma: A cooperative group study. J Clin Oncol15:2564-2569, 1997
5.
Roth BJ, Dreicer R, Einhorn LH, et al: Significant activity of paclitaxel in advanced transitional-cell carcinoma of the urothelium: A phase II trial of the Eastern Cooperative Oncology Group. J Clin Oncol12:2264-2270, 1994
6.
Stadler WM, Kuzel T, Roth B, et al: Phase II study of single-agent gemcitabine in previously untreated patients with metastatic urothelial cancer. J Clin Oncol15:3394-3398, 1997
7.
Moore MJ, Tannock IF, Ernst DS, et al: Gemcitabine: A promising new agent in the treatment of advanced urothelial cancer. J Clin Oncol15:3441-3445, 1997
8.
Witte RS, Elson P, Bono B, et al: Eastern Cooperative Oncology Group phase II trial of ifosfamide in the treatment of previously treated advanced urothelial carcinoma. J Clin Oncol15:589-593, 1997
9.
McCaffrey JA, Hilton S, Mazumdar M, et al: Phase II trial of docetaxel in patients with advanced or metastatic transitional-cell carcinoma. J Clin Oncol15:1853-1857, 1997
10.
Vaughn DJ, Malkowicz SB, Zoltick B, et al: Paclitaxel plus carboplatin in advanced carcinoma of the urothelium: An active and tolerable outpatient regimen. J Clin Oncol16:255-260, 1998 11. Redman BG, Smith DC, Flaherty L, et al: Phase II trial of paclitaxel and carboplatin in the treatment of advanced urothelial carcinoma. J Clin Oncol16:1844-1848, 1998[Abstract] 12. Droz JP, Mottet N, Prapotrich D, et al: Phase II study of Taxol (paclitaxel) and carboplatin in patients with advanced transitional-cell carcinoma of the urothelium: Preliminary results. Proc Am Soc Clin Oncol 17:316a, 1998 (abstr 1219) 13. Moore MJ, Tannock I, Winquist E, et al: Gemcitabine (G) + cisplatin (C): An active regimen in advanced transitional cell carcinoma (TCC). Proc Am Soc Clin Oncol 17:320a, 1998 (abstr 1234) 14. Kaufman D, Stadler W, Carducci M, et al: Gemcitabine (GEM) plus cisplatin (CDDP) in metastatic transitional cell carcinoma (TCC): Final results of a phase II study. Proc Am Soc Clin Oncol 17:320a, 1998 (abstr 1235) 15. Dreicer R, Roth B, Lipsitz S, et al: E2895 cisplatin and paclitaxel in advanced carcinoma of the urothelium: A phase II trial of the Eastern Cooperative Oncology Group (ECOG). Proc Am Soc Clin Oncol 17:320a, 1998 (abstr 1233) 16. Bellmunt J, Carles J, Climent MA, et al: Phase I trial of paclitaxel, cisplatin, and gemcitabine (TCG) in patients (pts) with advanced transitional cell carcinoma (TCC) of the urothelium. Proc Am Soc Clin Oncol 17, 1998 (abstr 1236) 17. Meyers FJ, Edelman MJ, Houston J, et al: Phase I/II trial of paclitaxel, carboplatin, and methotrexate in advanced transitional cell carcinoma. Proc Am Soc Clin Oncol 17:317a, 1998 (abstr 1222) 18. Bajorin DF, McCaffrey JA, Hilton S, et al: Treatment of patients with transitional-cell carcinoma of the urothelial tract with ifosfamide, paclitaxel, and cisplatin: A phase II trial. J Clin Oncol16:2722-2727, 1998[Abstract] 19. Geller NL, Sternberg CN, Penenberg D, et al: Prognostic factors for survival of patients with advanced urothelial tumors treated with methotrexate, vinblastine, doxorubicin, and cisplatin chemotherapy. Cancer67:1525-1531, 1991[Medline] 20. Gabrilove JL, Jakubowski A, Scher H, et al: Effect of granulocyte colony-stimulating factor on neutropenia and associated morbidity due to chemotherapy for transitional-cell carcinoma of the urothelium. N Engl J Med318:1414-1422, 1988[Abstract] 21. Dodd PM, McCaffrey JA, Mazumdar M, et al: Phase II trial of intermediate-dose methotrexate in combination with vinblastine, doxorubicin, and cisplatin in patients with unresectable or metastatic transitional cell carcinoma. Cancer85:1145-1150, 1999[Medline]
22.
Seidman AD, Scher HI, Gabrilove JL, et al: Dose-intensification of M-VAC with recombinant granulocyte colony-stimulating factor as initial therapy in advanced urothelial cancer. J Clin Oncol11:408-414, 1993
23.
McCaffrey JA, Hilton S, Mazumdar M, et al: Phase II randomized trial of gallium nitrate plus fluorouracil versus methotrexate, vinblastine, doxorubicin, and cisplatin in patients with advanced transitional cell carcinoma. J Clin Oncol15:2449-2455, 1997 24. Kaplan EL, Meier P: Nonparametric estimation from incomplete observations. J Am Stat Assoc53:457-481, 1958 25. Chen CH, George SL: The bootstrap and identification of prognostic factors vis Cox's proportional hazards regression model. Stat Med4:39-46, 1985[Medline] Submitted March 1, 1999; accepted June 10, 1999.
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Copyright © 1999 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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