Prognostic factors for survival in advanced non-small-cell lung cancer: univariate and multivariate analyses including recursive partitioning and amalgamation algorithms in 1,052 patients. The European Lung Cancer Working Party.

PURPOSE: This study attempted to determine the prognostic value for survival of various pretreatment characteristics in patients with nonresectable non-small-cell lung cancer in the context of more than 10 years of experience of a European Cooperative Group. PATIENTS AND METHODS: We included in the analysis all eligible patients (N = 1,052) with advanced non-small-cell lung cancer registered onto one of seven trials conducted by the European Lung Cancer Working Party (ELCWP) during one decade. The patients were treated by chemotherapy regimens based on platinum derivatives. We prospectively collected 23 variables and analyzed them by univariate and multivariate methods. RESULTS: The global estimated median survival time was 29 weeks, with a 95% confidence interval of 27 to 30 weeks. After univariate analysis, we applied two multivariate statistical techniques. In a Cox regression model, the selected explanatory variables were disease extent, Karnofsky performance status, WBC and neutrophil counts, metastatic involvement of skin, serum calcium level, age, and sex. These results were confirmed by application of recursive partitioning and amalgamation algorithms (RECPAM), which led to classification of the patients into four homogeneous subgroups. CONCLUSION: We confirmed by our analysis the role of well-known independent prognostic factors for survival, but also identified the effect of the neutrophil count, rarely studied, with the use of two methods: a classical Cox regression model and a RECPAM analysis. The classification of patients into the four subgroups we obtained needs to be validated in other series.

Randomized trial comparing induction chemotherapy versus induction chemotherapy followed by maintenance chemotherapy in small-cell lung cancer. European Lung Cancer Working Party.

PURPOSE AND METHODS: The European Lung Cancer Working Party (ELCWP) performed a randomized trial with the primary end point to determine if maintenance chemotherapy with 12 courses of etoposide (120 mg/m2 on days 1 and 3) and vindesine (3 mg/m2 on day 3) could improve progression-free survival in small-cell lung cancer (SCLC) patients who responded to six courses of induction chemotherapy with ifosfamide, etoposide, and an anthracycline (doxorubicin or epirubicin). RESULTS: Among 235 eligible patients initially registered, 91 were randomized to receive maintenance therapy, including seven patients who were no longer responding. Among 84 randomized responders, progression-free survival was significantly improved (P = .003) by maintenance therapy, with median durations (maintenance v follow-up) of 25 versus 12 weeks after the second randomization, but survival was not significantly increased (P = .10), with median durations of 48 and 38 weeks. However, in a multi-variate analysis that took into account disease extent, maintenance therapy, Karnofsky performance status (PS), and absolute dose-intensity (ADI) of anthracycline given during induction, limited disease (LD) and maintenance were found to be independent positive predictors of survival. CONCLUSION: We conclude that maintenance chemotherapy in responding patients is beneficial in SCLC.

Phase III randomized trial comparing cisplatin and carboplatin with or without ifosfamide in patients with advanced non-small-cell lung cancer. European Lung Cancer Working Party.

PURPOSE: A phase III randomized trial in patients with advanced non-small-cell lung cancer (NSCLC) was performed to determine if the addition of ifosfamide to moderate-dose cisplatin and carboplatin improved response rate (primary end point) and survival. PATIENTS AND METHODS: A total of 529 patients were randomized to receive a combination of moderate-dose carboplatin (200 mg/m2 intravenously [i.v.] on day 1) and cisplatin (30 mg/m2 i.v. on days 2 and 3) with (CCI arm) or without (CC arm) ifosfamide (1.5 g/m2 i.v. on days 1 to 3). There were 248 eligible patients on the CC arm and 257 on the CCI arm, with 220 and 238 patients assessable for response, respectively. All but 23 had stage IV disease with pleural effusion. RESULTS: There was a 16% objective response (OR) rate to CC and a 31% OR rate to CCI. That observed difference was highly statistically significant (P < 0.001). Duration of response and survival were not statistically different between arms. The CCI regimen was associated with significantly more acute toxicities: emesis, alopecia, leukopenia, and thrombocytopenia. The frequency of chronic renal, auditive, and peripheral neurologic toxicity was low in both arms (4.6% and 6.6%, respectively, after six courses of chemotherapy). The relative dose-intensity (RDI) of the CCI arm was significantly lower than that of the CC arm. CONCLUSION: The addition of ifosfamide to moderate-dose cisplatin and carboplatin significantly improves the antitumoral response rate, but has no apparent effect an survival in advanced NSCLC.

A phase II study evaluating the cisplatin and epirubicin combination in patients with unresectable malignant pleural mesothelioma.

Few chemotherapeutic agents have demonstrated their efficacy in malignant mesothelioma. The cisplatin plus doxorubicin combination has one of the highest response rates. Epirubicin is an anthracyclin, analogous to doxorubicin, with a different toxicologic pattern. As there are no data on the activity of the combination cisplatin plus epirubicin in malignant mesothelioma, the European Lung Cancer Working Party (ELCWP) designed a phase II study with response rate as primary objective. Sixty-nine eligible patients with malignant pleural mesothelioma were centrally registered. The majority of the patients were male (n=59), had a Karnofsky performance status of 80 or more (n=62) and presented with an epithelial histologic subtype (n=43). Median age was 62 years. In nine patients, metastases were documented at the initial work-up, mainly in bone, lung and skin. Three hundred and twenty-four cycles of chemotherapy were administered. The main toxicities were nausea and vomiting, neutropenia and alopecia. Among 63 assessable patients, response rate was 19.0% (95% confidence interval [CI] 9-29%). Median survival was 13.3 months. In multivariate analysis, poor prognostic factors for survival were neutrophil count and CALGB groups 4-6. In conclusion, cisplatin plus epirubicin appears as an effective regimen in malignant mesothelioma, with a favourable toxicity profile. However, it does not demonstrate superior activity to other active regimens in this disease.

Response to chemotherapy has predictive value for further survival of patients with advanced non-small cell lung cancer: 10 years experience of the European Lung Cancer Working Party.

The aim of this study was the assessment of the predictive value for survival of an antitumoral response to three courses of chemotherapy in association with various pretreatment characteristics in patients with non-resectable non-small cell lung cancer treated by cisplatin- (or carboplatin)-based combination regimens. Patients considered for this study were eligible patients with advanced non-small cell lung cancer registered in one of the seven trials conducted by the European Lung Cancer Working Party from December 1980 to August 1991. All these trials tested chemotherapy regimens with platinum derivatives (cisplatin and/or carboplatin). In this population of 1052 eligible patients, 752 were assessed in this analysis. Data were prospectively collected on 23 pretherapeutic variables and objective response after three chemotherapy cycles. The predictive value of response to chemotherapy on survival (measured from the time of response assessment i.e. 12 weeks after registration in the trial) was studied by univariate analysis as well as by multivariate methods (adjustment of the impact of several covariates simultaneously on the dependent variable) with adjustment for the pretreatment prognostic variables. After three cycles of chemotherapy, the global estimated median survival time was 24 weeks with a 95% confidence interval of 22-25 weeks. By univariate analysis, we identified an objective response to chemotherapy as a highly significant discriminant marker (P < 0.0001) for further survival with estimated median survival times of 41 weeks (95% CI: 38-46) and 19 weeks (95% CI: 17-20), respectively, for the responding and non-responding patients. In a Cox regression model fitted to the data using a forward stepwise procedure, this variable was the first selected explanatory variable. Its effect was adjusted by the introduction in the model of initial disease extent, Karnofsky performance status, serum calcium level and white blood cell count. These results were consistent with those obtained by application of recursive partitioning and amalgamation algorithms (RECPAM) which led to a classification of the patients into three homogeneous subgroups. Our results, using a classical Cox regression model consistent with those highlighted by application of a RECPAM analysis, found an objective response to chemotherapy to be a predominant predictive factor for further survival, although it did not allow any conclusion about a causal relationship. The RECPAM results led to a classification of the patients into three subgroups which needs to be validated in other series.

A comparison of methods of calculation for estimating carboplatin AUC with a retrospective pharmacokinetic-pharmacodynamic analysis in patients with advanced non-small cell lung cancer. European Lung Cancer Working Party.

We retrospectively analysed the data obtained in a large randomised trial performed in 505 eligible patients with advanced non-small cell lung cancer. Its purpose had been to compare a combination of carboplatin (200 mg/m2) and cisplatin (60 mg/m2) with or without the addition of ifosfamide. The present retrospective analysis assessed two ways of dosing carboplatin: according to body surface area (mg/m2) or to the estimated targeted area under the concentration versus time curve (AUC). Two different methods were used in the latter calculation: the Calvert formula using the Cockroft approximation to evaluate the glomerular filtration rate and the Chatelut equation. There was an excellent linear correlation between them. With the Chatelut method, the calculated administered AUC were lower. Whichever method was used, carboplatin AUC was not significantly associated with antitumour response rate nor patient survival. A statistically significant increase in haematological toxicity, mainly thrombopenia, was observed with an increase in the AUC. This effect was observed whatever AUC variable was considered, i.e. total dosage at course one, total dosage during the first three chemotherapy courses or dose intensity during the first three courses. The effect remained highly significant after adjustment for treatment arm. We conclude that for a moderate carboplatin dose in non-small cell lung cancer, the therapeutic index could be improved if dosage is calculated according to the AUC.

Induction chemotherapy with ifosfamide, etoposide, and anthracycline for small cell lung cancer: experience of the European Lung Cancer Working Party.

Prospective trials comparing drug analogues in the treatment of small cell lung cancer are rare. The European Lung Cancer Working Party has conducted a randomized trial with a primary end point of determining the effect on survival of maintenance chemotherapy and a secondary end point of comparing doxorubicin (45 mg/m2) with a bioequivalent epirubicin dose (60 mg/m2) in one set of patients, and a standard with a high epirubicin dose (60 v 90 mg/m2) in a second set of patients. Anthracycline was given on day 1 of induction chemotherapy in combination with ifosfamide (1.5 g/m2 intravenously days 1 through 3) and etoposide (80 mg/m2 intravenously days 1 through 3). Six courses were given at 3-week intervals. In all, 235 eligible previously untreated patients with pathologically proven small cell lung cancer were randomized: 106 to the comparison of doxorubicin and epirubicin and 129 to the comparison of standard-dose versus high-dose epirubicin. There was no difference between the regimens in terms of objective response rate or survival, and the regimen containing the lower (60 mg/m2) epirubicin dose was better tolerated, with fewer toxic deaths and less need for dose and schedule adjustments.

A phase-ii study testing a combination chemotherapy with epirubicin and vindesine as 2nd line treatment for patients with advanced non-small-cell lung-cancer.

The European Lung Cancer Working Party conducted a phase II trial to determine the activity of a salvage regimen with high dose epirubicin (120 mg/m(2) on day 1) and vindesine (3 mg/m(2) on day 1) in patients with advanced non-small cell lung cancer failing to respond to first-line chemotherapy containing cisplatin and/or carboplatin. Courses were repeated every 3 weeks and evaluation of antitumoral response was performed after the 2 first courses. A total of 53 patients were registered, 4 were not eligible and 42 were evaluable for response. Two (5%) objective responses were documented. Although the regimen was very well tolerated, based oh the results it has to be considered inactive.

A phase-ii study testing weekly platinum derivative combination chemotherapy as 2nd-line treatment in patients with advanced small-cell lung-cancer.

A phase II trial was conducted to determine the effectiveness of weekly administration of cisplatin (25 mg/m(2) on day 1) and carboplatin (100 mg/m(2) on day 1) as salvage chemotherapy for patients with small cell lung cancer after first-line chemotherapy without platinum derivatives. Of 40 eligible patients, 38 were evaluable for response. Interval between last course of first-line chemotherapy and first course of salvage therapy was less than 3 months in 34 and greater in 4. Five partial responses (13%; confidence interval at 95%:0.01-0.25) were documented (including 4 in patients with a treatment-free interval <3 months) as well as 8 no change, 21 progressions and 4 early deaths due to malignant disease. Toxicity consisted mainly of moderate thrombopenia and leucopenia. Grade I nephrotoxicity was observed in 6 patients. In conclusion, weekly administration of moderate doses of cisplatin and carboplatin as salvage chemotherapy for small cell lung cancer appeared feasible and was associated with a moderate but definitive anticancer activity.

A phase II trial testing gemcitabine as second-line chemotherapy for non small cell lung cancer. The European Lung Cancer Working Party. 101473.1044@compuserve.com.

The purpose of the present trial was to determine the activity of gemcitabine as a second-line chemotherapy for non small cell lung cancer (NSCLC). To be eligible, patients had to have pathologically proven NSCLC that has failed to respond to a first-line chemotherapy with a cisplatin-containing regimen, a Karnofsky performance status greater than 50 and adequate renal, haematological and hepatic functions. After registration, patients were treated by gemcitabine given i.v. at a dose of 1 g/m(2) on days 1, 8, 15 every 4 weeks. Response was assessed after two courses of therapy. Eighty-two patients have been registered, five are ineligible and 65 are assessable for response. Four partial responses were observed (6%). No change was documented in 18 cases (28%). Tolerance was good. A few grade III leucopenia and grade III-IV thrombopenia were observed. We conclude that gemcitabine has a modest activity as second-line chemotherapy for NSCLC. It has the advantage to be well tolerated and may thus be one drug to be proposed to the patients who have disease progression after a first-line chemotherapy and who ask for further treatment.

A phase II study testing paclitaxel as second-line single agent treatment for patients with advanced non-small cell lung cancer failing after a first-line chemotherapy.

The purpose of this study was to determine the activity of paclitaxel as a second-line chemotherapy for non-small cell lung cancer (NSCLC). This multicentric trial included patients who had failed to a first-line chemotherapy with platinum derivatives and/or ifosfamide. After registration, patients were treated by paclitaxel i.v. at a dose of 225 mg/m(2) given over 3 h administered every 3 weeks. Response was assessed after three courses of therapy. Sixty-seven patients were registered, one was ineligible and 64 were assessable for response. Two partial responses were observed (3% of the eligible patients; 95% confidence interval: 0-7%). No change was documented in 16 cases (24%). Tolerance was acceptable, the main toxicity being cumulative polyneuropathy. Median survival duration was 4.5 months with a 1-year rate at 19%. We concluded that paclitaxel is not active in terms of response as second-line chemotherapy for NSCLC.

Prognostic factors for response to chemotherapy containing platinum derivatives in patients with unresectable non-small cell lung cancer. (NSCLC).

PURPOSE: To identify pretreatment variables predicting response to platinum derivatives containing chemotherapy in patients with unresectable non-small cell lung cancer (NSCLC). PATIENTS AND METHODS: Eligible patients included in one of the 7 consecutive clinical trials conducted by the European Lung Cancer Working Party between December 1980 and August 1991. All patients received a cisplatin or carboplatin containing chemotherapy. We analyzed 22 potential prognostic factors including sex, age, histology, performance status, weight loss, type of lesions, extent of disease, main metastatic sites and several biological parameters, namely white blood cell count (WBC), neutrophil count, platelet count, hemoglobinemia, creatininemia, serum alkaline phosphatases and LDH. RESULTS: On 1052 eligible patients. 107 were not assessable for response. The objective response rate was 26% (95% C.I.: 23, 29%). Univariate analysis identified as statistically significantly associated with a higher objective antitumoral response rate the following characteristics: a normal platelet count, the absence of skin metastasis, the absence of adrenal metastasis, a higher creatininemia, a normal hemoglobinemia, an older age and a normal WBC count. On a restricted set of variables including data from 777 patients, a multivariate logistic regression model disclosed age and platelet count as significantly and independently related to response rate. CONCLUSION: Clinical and demographic characteristics of patients with unresectable NSCLC, as well as routine laboratory parameters, could not accurately predict response to chemotherapy in a population of patients selected for a clinical trial. Future studies on this subject should include more sophisticated variables as new biomolecular makers.

Survival is better predicted with a new classification of stage III unresectable non-small cell lung carcinoma treated by chemotherapy and radiotherapy.

UNLABELLED: The 1997 International staging system (ISS) classification separated stage III non-small cell lung cancer (NSCLC) into stages IIIA and IIIB. In a previous study including unresectable NSCLC initially treated with chemotherapy, we analysed survival according to tumour (T) and node (N) stages and derived a classification into stages IIIbeta (T3-4N3) and IIIalpha (other TN stage III) that had a better discrimination on survival distribution. The aim of this study was to validate these results in a further set of patients. Patients with unresectable stage III NSCLC included in a phase III trial assessing the role of increased dose chemotherapy (SuperMIP: mitomycin 6 mg/m2, ifosfamide 4.5 g/m2, cisplatin 60 mg/m2, carboplatin 200 mg/m2) in comparison to standard chemotherapy MIP (mitomycin 6 mg/m2, ifosfamide 3 g/m2, cisplatin 50 mg/m2), before thoracic irradiation (60 Gy in 30 fractions over 6 weeks) were the subject of this study. Survival distributions were assessed by the method of Kaplan-Meier. Survival comparisons were made by the log-rank test. Multivariate analyses using Cox regression models, included all potential prognostic factors for survival with a P-value <0.2 in univariate analysis. According to the 1997 International staging system classification, 328 eligible patients were included in the study. There was no imbalance between the two arms. Five parameters were significantly associated (P < or = 0.05) with survival in univariate analysis: European lung cancer working party (ELCWP) staging (IIIalpha[n = 294 pts] versus IIIbeta [n = 46]), Karnofsky index, weight loss, platelet count and haemoglobin level. These variables as well as the 1997 ISS staging, white blood cell (WBC) count, LDH and sodium levels were included in a multivariate analysis. Two models were constructed, including either the ELCWP or the 1997 ISS. In model 1 (ISS included), Karnofsky index (HR 0.69; 95% confidence interval (CI) 0.47-1.00; P = 0.05) and haemoglobin (HR 1.49; 95% CI 1.11-1.99; P = 0.007) were found significant. In model 2, including ELCWP staging, two variables were associated with survival: ELCWP staging (HR 1.68; 95% CI 1.20-2.35; P = 0.002) and haemoglobin (HR 1.54; 95% CI 1.15-2.07; P = 0.01). CONCLUSION: In initially unresectable stage III NSCLC treated by chemotherapy and radiotherapy, we validated the results of our previous study. The classification into stages IIIbeta (T3-4N3M0) and IIIalpha (other TN stage III) better discriminates the patients in term of survival than the 1997 ISS classification.

Evaluation of the TN sub-staging in patients with initially unresectable stage III non-small cell lung cancer treated by induction chemotherapy. The European Lung Cancer Working Party.

PURPOSE: This study attempted to investigate, in a cohort of patients with clinical stage III initially unresectable non-small cell lung cancer (NSCLC) treated by the same induction chemotherapy regimen, the prognostic value of clinical T and N sub-groupings in order to validate the current International Staging System (ISS). PATIENTS AND METHODS: All the eligible patients with stage III NSCLC (428 patients) registered in a clinical trial were included in the study investigating, after three courses of induction chemotherapy, the role, in responders, of chest irradiation in comparison to further chemotherapy. The chemotherapy regimen consisted of mitomycin C, ifosfamide and cisplatin. RESULTS: Patients with ISS 1986 stage IIIA had a significantly better survival than those with stage IIIB (median survival 47 vs 36 weeks; P = 0.01). A RECPAM analysis showed that patients with T1-T2 N3 and T4 N0-1-2 stage had a more similar prognosis to those with stage IIIA. That result leads to define two new sub-groups: stage IIIlalpha (T3-T4 N0-N1; any T N2; T1-T2 N3) and IIIbeta (T3-T4 N3), with a highly significant difference in survival between them (median survival: 45 vs 29 weeks; P < 0.0001). The superiority of that new classification on the ISS documented in our series of stage III patients for discriminating survival and tumour response has to be confirmed on another series in a multivariate context. CONCLUSION: For unresectable NSCLC treated by induction chemotherapy, stage III sub-classification by moving T4 N0-1 and T1-2 N3 tumours from stage IIIB to stage IIIA appeared to better correlate with prognosis. The usefulness of this new sub-division has to be tested in validation studies.

Cisplatin-carboplatin-gemcitabine or ifosfamide-gemcitabine in advanced non-small cell lung carcinoma: two pilot studies.

Gemcitabine has been demonstrated active in non-small cell lung cancer (NSCLC). The objective of this trial was to evaluate the feasibility of combinations of gemcitabine (1 g/m2 dl,8,15) with cisplatin (60 mg/m2 dl) and carboplatin (200 mg/m2 dl) (CCG; n = 12) or ifosfamide (4.5 g/m2 dl) (IG;n = 4) in patients with advanced NSCLC, in order to prepare a phase III randomised trial. Toxicity, mainly haematological, was tolerable. It consisted in neutropenia (IG) and both thrombopenia and neutropenia (CCG). The administration of carboplatin according to the AUC (AUC = 3) resulted in a significant reduction of haematological toxicity. A good number of responses were documented. These acceptable results urged our group to compare these regimens to the combination of cisplatin, carboplatin and if osfamide.

[Prognostic factors in advanced stage non-small cell bronchial cancer: experiences of the European Lung Cancer Working Party]. / Facteurs pronostiques des cancers bronchiques non à petites cellules au stade avancé: expérience de l'European Lung Cancer Working Party.

The European Lung Cancer Working Party has investigated prognostic factors for response, overall survival, long term survival in a population with advanced non small cell lung cancer registered in a clinical trial evaluating platinum derivatives-containing chemotherapy regimens. Various factors have been identified in multivariate analyses and were classified using RECPAM methodology. In addition to the clinical factors such as disease extent and performance status were shown, as significant predictors, rarely studied biological factors like pretherapeutic leucocyte and polynuclear levels. The obtention of an objective response to chemotherapy appeared to be a major prognostic factor for further survival.

Complete remissions in non small cell lung cancer.

We studied 241 patients with non small cell bronchogenic cancer who were treated with cisplatin and etoposide or cisplatin, etoposide and vindesine. There were 11 (4.5%) complete responders in these series most of whom had a prolonged survival.

Placebo controlled pneumococcal immunization in patients with bronchogenic carcinoma.

Pneumococcal vaccine [heptadecavalent types 1, 2, 3, 4, 6A, 7F, 8, 9N, 11A, 12F, 14, 15F, 17F, 18C, 19F, 23F and 25 pneumococcal capsular polysaccharide vaccine (Moniarix)] or placebo were evaluated in 26 and 21 patients with bronchogenic carcinoma, most of whom did not receive prior radiotherapy or chemotherapy. No difference was detected as far as clinical outcome is concerned: 3 vaccinated patients out of 26 (11.5%) developed pneumococcal infections (1 fatal bacteremia) and 4/21 (19%) of those who received a placebo presented such an infection (1 fatal bacteremia). The antibody response was significantly increased in the vaccines for types 1, 2, 7F, 8, 9N, 12F, 14, 17F, 18C, 23F and 25.

Subrenal capsule assay of fresh human tumors: problems and pitfalls.

The 6 day subrenal capsule (SRC) assay was performed in normal mice using 20 fresh human non-small cell lung cancers and nine fresh ovarian cancers. Different multi-agent chemotherapy regimens administered intravenously on days 2 + 3 of the assay were evaluated for activity against these two tumor types. Macroscopic results measured via an ocular microscope showed high activity for some combinations as well as for single agents. However, when subjected to microscopic examination, the SRC implants in the untreated control animals did not show viable tumor growth on day 6. Detailed histologic evaluation of over 800 SRC grafts reveals an intense inflammatory and fibrotic reaction in the majority of the grafts. These results indicate that drug sensitivity patterns obtained with this assay using only macroscopic criteria do not correlate with actual tumor regression. Microscopic analysis of the grafts prior to transplant shows absence or only minimal presence of tumor in many cases which also contributes to the poor growth observed in these two tumors.

A preliminary evaluation of calcitonin and PDN-21 as tumor markers for lung cancer. EORTC Lung Cancer Working Party.

Immunoreactive calcitonin (iCT) can be ectopically secreted by lung cancer cells and has been proposed as a tumor marker for bronchial neoplasms. Since PDN-21 (katacalcin or the carboxyl-terminal flanking peptide of the calcitonin gene) and CT are cosecreted in normal subjects and in patients with medullary thyroid carcinoma (MTC), we sought to determine the potential utility of PDN-21 as a tumor marker for lung cancer. We measured carcinoembryonic antigen (CEA), neurone-specific enolase (NSE), iCT, and PDN-21 in 119 to 378 healthy subjects, 88 to 91 patients with benign pulmonary disease, and 249 patients with advanced lung cancer (108 small cell lung cancers and 141 other forms). Tumor marker specificity was satisfactory: the percentage of increased values (greater than the 95th percentile of normal subjects) in patients with benign pulmonary diseases varied from 9% (NSE, PDN-21) to 12% (CEA). PDN-21 was a more sensitive marker for lung cancer than iCT: the percentage of increased values was 44% for PDN-21 versus 19% for iCT, and 51% versus 23% for the subgroup of patients with small cell lung cancer (SCLC). PDN-21 concentrations were increased in 69 (34%) of 202 patients with a normal iCT level, whereas iCT concentrations were increased in only six (4%) of 139 patients with a normal PDN-21 level. However, markedly elevated concentrations of the two markers generally occurred in the same patients and the correlation between the two markers was significant (rs = 0.60; P less than 0.01). PDN-21 provided complementary information to that from the classical markers NSE and CEA.(ABSTRACT TRUNCATED AT 250 WORDS)