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Dive into the research topics where Tjebbe C. Kok is active.

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Featured researches published by Tjebbe C. Kok.


Journal of Clinical Oncology | 1998

Evaluation of antiandrogen therapy in unresectable hepatocellular carcinoma: results of a European Organization for Research and Treatment of Cancer multicentric double-blind trial.

C Grimaldi; Harry Bleiberg; M Messner; P. Rougier; Tjebbe C. Kok; L Cirera; A Cervantes; J.-P. De Greve; B. Paillot; M Buset; D Nitti; Tarek Sahmoud; N Duez; Jacques Wils

PURPOSE The aim of the study was to evaluate the efficacy of antiandrogen therapy on overall survival and response in unresectable hepatocellular carcinoma (HCC). PATIENTS AND METHODS A total of 244 patients with unresectable HCC were included in this multicentric double-blind trial. According to a two-by-two factorial design, patients were randomly assigned to receive one of the following treatments: pure antiandrogen plus placebo (A+P group, 60 patients); luteinizing hormone-releasing hormone (LHRH) agonist plus placebo (LHRH+P group, 62 patients); pure antiandrogen plus LHRH agonist (A+LHRH group, 62 patients); or placebo plus placebo (P+P group, 60 patients). Pure antiandrogen consisted of Anandron (Roussel-Uclaf Laboratory, Romainville, France) administered orally (300 mg daily for 1 month, then 150 mg daily). LHRH consisted of goseriline acetate (3.6 mg) or triptoreline (3.75 mg) administered monthly by subcutaneous injection. Treatment was given until death. Response was evaluated every 8 weeks according to World Health Organization (WHO) criteria. RESULTS Six patients were considered ineligible. One patient had a complete response (A+P arm) and three had a partial response (two in the LHRH+P arm and one in the A+LHRH arm). An overall log-rank test did not demonstrate any significant difference in survival among the four arms. Taking the factorial design into account, comparison of survival showed no significant difference between Anandron-containing regimens and others, or between LHRH-containing regimens and others. No serious side effects occurred for any regimen. CONCLUSION This controlled study shows clearly the lack of efficacy of androgen treatment in unresectable HCC.


British Journal of Cancer | 1994

Evaluation of a new tumour marker in patients with non-small-cell lung cancer: Cyfra 21.1.

A. van der Gaast; C.H.H. Schoenmakers; Tjebbe C. Kok; B.G. Blijenberg; F. Cornillie; Ted A.W. Splinter

The Cyfra 21.1 assay is a newly developed test which measures in serum a fragment of cytokeratin 19. We evaluated this marker in 212 patients with non-small-cell lung cancer (NSCLC), predominantly stage 3a-b and 4, and compared it with three other markers: carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCC) and tissue polypeptide antigen (TPA). Sensitivities for Cyfra 21.1, TPA, CEA and SCC (using cut-off levels corresponding to a 95% specificity for benign lung diseases) were 40%, 40%, 42% and 19% respectively. The sensitivity of CEA was significantly higher in patients with adenocarcinomas compared with the other three markers, while the sensitivity of Cyfra 21.1 and TPA was significantly higher in patients with squamous cell carcinomas. The value of Cyfra 21.1 for monitoring disease during chemotherapy could be evaluated in 23 patients with squamous cell carcinomas. When the cases of lead time were included a concordance between clinical evaluations according to WHO response criteria and evaluations according to changes in the marker levels of 74% was found. The criteria defined for marker response were a 65% decrease in the marker level for a partial response and a 40% increase for progressive disease. In particular, increasing levels of this marker indicated usually disease progression. In conclusion, Cyfra 21.1 is a useful serum marker for patients with NSCLC, especially for disease monitoring of patients with squamous cell carcinoma during and after chemotherapy.


BMC Cancer | 2011

Chemotherapy followed by surgery versus surgery alone in patients with resectable oesophageal squamous cell carcinoma: Long-term results of a randomized controlled trial

Jurjen J. Boonstra; Tjebbe C. Kok; Bas P. L. Wijnhoven; Mark van Heijl; Mark I. van Berge Henegouwen; Fiebo J. ten Kate; Peter D. Siersema; Winand N. M. Dinjens; J. Jan B. van Lanschot; Hugo W. Tilanus; Ate van der Gaast

BackgroundThis is a randomized, controlled trial of preoperative chemotherapy in patients undergoing surgery for oesophageal squamous cell carcinoma (OSCC). Patients were allocated to chemotherapy, consisting of 2-4 cycles of cisplatin and etoposide, followed by surgery (CS group) or surgery alone (S group). Initial results reported only in abstract form in 1997, demonstrated an advantage for overall survival in the CS group. The results of this trial have been updated and discussed in the timeframe in which this study was performed.MethodsThis trial recruited 169 patients with OSCC, 85 patients assigned to preoperative chemotherapy and 84 patients underwent immediate surgery. The primary study endpoint was overall survival (OS), secondary endpoints were disease free survival (DFS) and pattern of failure. Survival has been determined from Kaplan-Meier curves and treatment comparisons made with the log-rank test.ResultsThere were 148 deaths, 71 in the CS and 77 in the S group. Median OS time was 16 months in the CS group compared with 12 months in the S group; 2-year survival rates were 42% and 30%; and 5-year survival rates were 26% and 17%, respectively. Intention to treat analysis showed a significant overall survival benefit for patients in the CS group (P = 0.03, by the log-rank test; hazard ratio [HR] 0.71; 95%CI 0.51-0.98). DFS (from landmark time of 6 months after date of randomisation) was also better in the CS-group than in the S group (P = 0.02, by the log-rank test; HR 0.72; 95%CI 0.52-1.0). No difference in failure pattern was observed between both treatment arms.ConclusionsPreoperative chemotherapy with a combination of etoposide and cisplatin significantly improved overall survival in patients with OSCC.


British Journal of Cancer | 2003

Prognostic factors for survival in patients with advanced oesophageal cancer treated with cisplatin-based combination chemotherapy

M. B. Polee; Wim C. J. Hop; Tjebbe C. Kok; F. Eskens; M.E.L. van der Burg; Ted A.W. Splinter; P. D. Siersema; H. W. Tilanus; G. Stoter; A. van der Gaast

The objective of this study was to identify prognostic factors for survival in patients with advanced oesophageal cancer, who are treated with cisplatin-based combination chemotherapy. We analysed the baseline characteristics of 350 patients who were treated in six consecutive prospective trials with one of the following regimens: cisplatin/etoposide, cisplatin/etoposide/5-fluorouracil, cisplatin/paclitaxel (weekly) and cisplatin/paclitaxel (biweekly). Predictive factors in univariate analyses were further evaluated using multivariate analysis (Cox regression). The median survival of all patients was 9 months. The 1, 2 and 5-year survival rates were 33, 12 and 4%, respectively. The main prognostic factors were found to be WHO performance status (0 or 1 vs 2), lactate dehydrogenase (normal vs elevated), extent of disease (limited disease defined as locoregional irresectable disease or lymph node metastases confined to either the supraclavicular or celiac region vs extensively disseminated disease) in addition to the type of treatment (weekly or biweekly cisplatin/paclitaxel regimen vs 4-weekly cisplatin/etoposide with or without 5-fluorouracil). Although weight loss, liver metastases and alkaline phosphatase were significant prognostic factors in univariate analyses, these factors lost their significance in multivariate analyses. The median survival for patients without any risk factors was 12 months, compared to only 4 months in patients with WHO 2 plus elevated LDH and extensive disease. The performance status, extent of disease, LDH and the addition of paclitaxel to cisplatin are independent prognostic factors in patients with advanced oesophageal cancer, who are treated with cisplatin-based combination chemotherapy.


European Journal of Cancer | 1997

No evidence of known types of human papillomavirus in squamous cell cancer of the oesophagus in a low-risk area

Tjebbe C. Kok; Kees Nooter; Steven P. Tjong-A-Hung; Henk L. Smits; J. ter Schegget

Controversial results regarding the presence and role of human papillomavirus in the development of oesophageal squamous cell carcinoma have been published. We used multiple broad-spectrum polymerase chain reactions to identify HPV DNA in oesophageal carcinomas from a low-incidence area. Paraffin embedded- and snap-frozen specimens from oesophageal cancer tissues of 63 patients were examined with a PCR technique with several primer pairs, capable of detecting most known HPV types. In none of the oesophagus cancer tissues could HPV DNA be detected. The role of HPV in this type of carcinoma in a low incidence area remains unclear.


British Journal of Cancer | 1999

Phase I study of a biweekly schedule of a fixed dose of cisplatin with increasing doses of paclitaxel in patients with advanced oesophageal cancer

A. van der Gaast; Tjebbe C. Kok; L. Kerkhofs; P. D. Siersema; H. W. Tilanus; Ted A.W. Splinter

SummaryWe performed this dose-finding study with a fixed dose of cisplatin and increasing doses of paclitaxel given every 2 weeks to determine the maximum tolerable dose of this schedule. Sixty-four patients with advanced oesophageal cancer were treated with a cisplatin dose of 60 mg m–2 and increasing doses of paclitaxel from 100 mg m–2 up to 200 mg m–2 both administered over 3 h for a maximum of six cycles in patients with stable disease or eight cycles in responding patients. Patients were retreated when the granulocytes were > 0.75 × 109 l–1 and the platelets > 75 × 109 l–1. The dose of paclitaxel could be increased to 200 mg m–2 without encountering dose limiting haematological toxicity. At the dose levels 190 mg m–2 and 200 mg m–2 of paclitaxel cumulative sensory neurotoxicity became the dose-limiting toxicity. The dose intensity of paclitaxel calculated over six cycles rose from 50 mg m–2 per week to 85 mg m–2 per week. Only three episodes of granulocytopenic fever were encountered out of a total of 362 cycles of treatment. Of the 59 patients evaluable for response, 31 (52%) had a partial or complete response. In a biweekly schedule with a fixed dose of 60 mg m–2 cisplatin it is possible to increase the dose of paclitaxel to 180 mg m–2. At higher dose levels, neurotoxicity becomes the dose-limiting toxicity. The observed response rate warrants further investigation of this schedule.


Anti-Cancer Drugs | 2001

Phase II study of the combination cisplatin, etoposide, 5-fluorouracil and folinic acid in patients with advanced squamous cell carcinoma of the esophagus.

M. B. Polee; Tjebbe C. Kok; P. D. Siersema; H. W. Tilanus; Ted A.W. Splinter; G. Stoter; A. Van Der Gaast

The objective of this study was to determine the toxicity and the efficacy of the combination of cisplatin, etoposide, 5-fluorouracil (5-FU) and folinic acid in the treatment of patients with advanced squamous cell carcinoma of the esophagus. Patients received cisplatin 80 mg/m2 i.v. on day 1, etoposide 125 mg/m2 i.v. on day 1 and etoposide 200 mg/m2 p.o. on days 3 and 5, 5-FU 375 mg/m2/day continuously i.v. combined with folinic acid 30 mg p.o. 6 times per day on days 1-4. Courses were repeated every 4 weeks until progression or up to a maximum of 6 courses. Patients were evaluated for response after every two courses. Sixty-nine patients received a total of 291 courses (median 4, range 1-6). The hematological toxicity consisted of leukocytopenia grade 3 or 4 in 17 and 16% of patients, respectively. Leukocytopenic fever was seen in 19% of patients. Thrombocytopenia grade 3 or 4 was seen in 13 and 7% of patients, respectively. Non-hematological toxicity consisted of nausea/vomiting grade 3 in 32%, diarrhea grade 3 in 6% and mucositis grade 3 or 4 in 23% of patients. The overall response rate was 34% (complete response 4%, partial response 30%) and the median time to progression was 7 months in 13 patients who received no additional treatment. The median survival for all patients was 9.5 months with a 1-year survival rate of 36%. Ten patients with initially locally unresectable disease (N=2) or celiac or supraclavicular lymph node metastases (N=8) who received additional treatment (esophageal resection in seven patients and radiotherapy in three patients) after they had responded to chemotherapy had a 3-year survival of 50%. We conclude that the combination cisplatin and etoposide combined with 5-FU and folinic acid is a safe and active regimen for patients with advanced squamous cell carcinoma of the esophagus. Mucositis is the most prevalent toxicity.


British Journal of Cancer | 1996

Cisplatin and etoposide in oesophageal cancer: a phase II study. Rotterdam Oesophageal Tumour Study Group.

Tjebbe C. Kok; A. van der Gaast; Jan Dees; W. M. H. Eykenboom; H. Van Overhagen; G. Stoter; H. W. Tilanus; Ted A.W. Splinter

In the search for effective chemotherapy regimens which can be used in multimodality treatment programmes for patients with cancer of the oesophagus, we conducted a phase II trial to determine the activity and toxicity of the combination of cisplatin and etoposide in patients with advanced squamous cell carcinoma of the oesophagus. Seventy-three consecutive patients with unresectable or metastatic squamous cell carcinoma of the thoracic oesophagus were treated with cisplatin 80 mg m-2 by 4 h infusion on day 1, etoposide 100 mg (fixed dose) by 2 h infusion on day 1 and 2, and etoposide 200 mg m-2 orally on day 3 and 5. Courses were repeated every 4 weeks, for a maximum of six courses. The oral dosages of etoposide were modified individually until a significant degree of myelosuppression was reached. Of 65 evaluable patients, five complete responses (CRs) and 26 partial responses (PRs) were seen, for an overall response rate of 48% (95% confidence interval 35-60%). Median time to progression was 7 months (range 3-72 + months). There were two toxic deaths (neutropenic sepsis). The response rate equals that of other cisplatin-based regimens. Its toxicity profile allows addition of a third active drug such as 5-fluorouracil.


European Urology | 1991

Growing Teratoma Syndrome Successfully Treated with Lymphoblastoid Interferon

A. Van Der Gaast; Tjebbe C. Kok; Ted A.W. Splinter

In most instances mature teratoma can be successfully resected following chemotherapy for advanced testicular cancer. However, some patients may eventually die because of uncontrollable local growth of an unresectable growing mature teratoma. This is a report on a patient with an unresectable growing mature teratoma in whom a long-lasting disease stabilization was achieved after treatment with lymphoblastoid interferon.


European Journal of Cancer | 1992

A phase I study of local treatment of liver metastases with recombinant tumour necrosis factor

George P. van der Schelling; Jan N. M. IJzermans; Tjebbe C. Kok; Marcel Scheringa; Richard L. Marquet; Ted A.W. Splinter; Johannes Jeekel

15 patients with therapy-resistant liver metastases were treated in a phase I study with recombinant tumour necrosis factor (rTNF). rTNF was injected into a liver metastasis by ultrasound guidance, using a 50 micrograms escalating dose schedule (3 patients/dosage) ranging from 100 to 350 micrograms per injection. Influenza-like symptoms such as fever, chills, nausea and vomiting were the main clinical side-effects. 2 patients experienced transient hypotension, probably due to concomitant use of morphine. Other toxicities, as reported after systemic use of rTNF, such as decrease in leucocytes and platelet counts, renal or liver toxicity were not observed. No difference was seen in subpopulations of lymphocytes (CD3+, CD4+, CD8+, CD16+ and CD19+) prior to and after rTNF injection. In 8 patients stable disease occurred in rTNF-treated metastases. The maximal dose used by this route of administration is 350 micrograms per injection. Based on these observations we conclude that the toxicity of rTNF injected into liver metastases by sonographic control is transient and mild. The results suggest that intratumoral administration of rTNF might play a role in local tumour control.

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Ted A.W. Splinter

Erasmus University Rotterdam

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A. van der Gaast

Erasmus University Rotterdam

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Ate van der Gaast

Erasmus University Rotterdam

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H. W. Tilanus

Erasmus University Rotterdam

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J.-P. De Greve

Vrije Universiteit Brussel

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G. Stoter

Erasmus University Medical Center

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Hugo W. Tilanus

Erasmus University Rotterdam

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Jan Dees

Erasmus University Rotterdam

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P. D. Siersema

Erasmus University Medical Center

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