Rob M. van Os
University of Amsterdam
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Featured researches published by Rob M. van Os.
Journal of Clinical Oncology | 2014
Vera Oppedijk; Ate van der Gaast; J. Jan B. van Lanschot; Pieter van Hagen; Rob M. van Os; Caroline M. van Rij; Maurice van der Sangen; Jannet C. Beukema; H.J.T. Rutten; Patty H. Spruit; Janny G. Reinders; Dick J. Richel; Mark I. van Berge Henegouwen; Maarten C. C. M. Hulshof
PURPOSEnTo analyze recurrence patterns in patients with cancer of the esophagus or gastroesophageal junction treated with either preoperative chemoradiotherapy (CRT) plus surgery or surgery alone.nnnPATIENTS AND METHODSnRecurrence pattern was analyzed in patients from the previously published CROSS I and II trials in relation to radiation target volumes. CRT consisted of five weekly courses of paclitaxel and carboplatin combined with a concurrent radiation dose of 41.4 Gy in 1.8-Gy fractions to the tumor and pathologic lymph nodes with margin.nnnRESULTSnOf the 422 patients included from 2001 to 2008, 418 were available for analysis. Histology was mostly adenocarcinoma (75%). Of the 374 patients who underwent resection, 86% were allocated to surgery and 92% to CRT plus surgery. On January 1, 2011, after a minimum follow-up of 24 months (median, 45 months), the overall recurrence rate in the surgery arm was 58% versus 35% in the CRT plus surgery arm. Preoperative CRT reduced locoregional recurrence (LRR) from 34% to 14% (P < .001) and peritoneal carcinomatosis from 14% to 4% (P < .001). There was a small but significant effect on hematogenous dissemination in favor of the CRT group (35% v 29%; P = .025). LRR occurred in 5% within the target volume, in 2% in the margins, and in 6% outside the radiation target volume. In 1%, the exact site in relation to the target volume was unclear. Only 1% had an isolated infield recurrence after CRT plus surgery.nnnCONCLUSIONnPreoperative CRT in patients with esophageal cancer reduced LRR and peritoneal carcinomatosis. Recurrence within the radiation target volume occurred in only 5%, mostly combined with outfield failures.
Neuro-oncology | 2012
Hanna van Alkemade; Michelle de Leau; E.M.T. Dieleman; Jan W.P.F. Kardaun; Rob M. van Os; W. Peter Vandertop; Wouter R. van Furth; Lukas J.A. Stalpers
PURPOSEnTo assess long-term functional outcome and survival among patients with meningioma World Health Organization (WHO) grade I.nnnMETHODSnRetrospective analysis of 205 patients after resection of WHO grade I intracranial meningioma from 1985 through 2003. Expected age- and sex-specific survival was calculated by applying Dutch life-table statistics to each patient for the individual duration of follow-up. Long-term functional outcome was assessed using a mailed questionnaire to the general practitioner.nnnRESULTSnThe mean duration of follow-up was 11.5 years. Survival at 5, 10, 15, and 20 years was 92%, 81%, 63%, and 53%, respectively, which is significantly lower than the expected survival (94%, 86%, 78%, and 66%, respectively). Survival was worse with higher age (P < .001). Survival among patients younger than 45 years and older than 65 years was comparable to the expected survival but significantly worse among patients aged 45-65 years. Analysis of the cause of death suggests an excess mortality associated with both brain tumor death and stroke (P = .07). Recurrence rates at 5, 10, and 15 years were 18%, 26%, and 32%, respectively. Higher Simpson grade (P < .001) and lower age (P = .02) were associated with a higher recurrence rate. In 29 patients (14%) receiving radiotherapy, the 5-year recurrence rate was 18% and the 5-year survival was only 58%. Long-term functioning (≥ 5 years after last treatment) could be assessed in 89 long-term survivors: 29 patients (33%) showed no deficits, and 60 (67%) showed at least 1 neurological symptom, of whom 24 (27%) were unable to perform normal daily activities.nnnCONCLUSIONnLong-term survival in WHO grade I meningioma is challenged in patients more than 45 years of age. Excess mortality seems to be associated with both tumor recurrence and stroke. The majority of patients have long-term neurological problems.
Advances in Experimental Medicine and Biology | 1990
Jan D.P. Van Dijk; Christoph Schneider; Rob M. van Os; Leo E. C. M. Blank; Dionisio Gonzalez Gonzalez
The purpose of this report is to present results of work in progress on hyperthermia treatment planning and clinical application of a fourapplicator phased array hyperthermia system for heating of large and deepseated tumors.
International Journal of Radiation Oncology Biology Physics | 2009
Alejandra Méndez Romero; Roel Th. Zinkstok; Wouter Wunderink; Rob M. van Os; Hans Joosten; Yvette Seppenwoolde; Peter J.C.M. Nowak; Rene P. Brandwijk; Cornelis Verhoef; Jan N. M. IJzermans; Peter C. Levendag; B.J.M. Heijmen
PURPOSEnTo assess day-to-day differences between planned and delivered target volume (TV) and organ-at-risk (OAR) dose distributions in liver stereotactic body radiation therapy (SBRT), and to investigate the dosimetric impact of setup corrections.nnnMETHODS AND MATERIALSnFor 14 patients previously treated with SBRT, the planning CT scan and three treatment scans (one for each fraction) were included in this study. For each treatment scan, two dose distributions were calculated: one using the planned setup for the body frame (no correction), and one using the clinically applied (corrected) setup derived from measured tumor displacements. Per scan, the two dose distributions were mutually compared, and the clinically delivered distribution was compared with planning. Doses were recalculated in equivalent 2-Gy fraction doses. Statistical analysis was performed with the linear mixed model.nnnRESULTSnWith setup corrections, the mean loss in TV coverage relative to planning was 1.7%, compared with 6.8% without corrections. For calculated equivalent uniform doses, these figures were 2.3% and 15.5%, respectively. As for the TV, mean deviations of delivered OAR doses from planning were small (between -0.4 and +0.3 Gy), but the spread was much larger for the OARs. In contrast to the TV, the mean impact of setup corrections on realized OAR doses was close to zero, with large positive and negative exceptions.nnnCONCLUSIONSnDaily correction of the treatment setup is required to obtain adequate TV coverage. Because of day-to-day patient anatomy changes, large deviations in OAR doses from planning did occur. On average, setup corrections had no impact on these doses. Development of new procedures for image guidance and adaptive protocols is warranted.
International Journal of Hyperthermia | 2010
S. Oldenborg; Rob M. van Os; Caroline M. Van rij; J. Crezee; Jeroen B. van de Kamer; Emiel J. Th. Rutgers; Elisabeth D. Geijsen; Paul J. Zum Vörde Sive Vörding; Caro C.E. Koning; Geertjan van Tienhoven
Purpose: To analyse the therapeutic effect and toxicity of re-irradiation (re-RT) combined with hyperthermia (HT) following resection or clinically complete remission (CR) of persistent locoregional recurrent breast cancer in previously irradiated area. Methods and materials: Between 1988 and 2001, 78 patients with high risk recurrent breast cancer underwent elective re-RT and HT. All patients received extensive previous treatments, including surgery and high-dose irradiation (≥50Gy). Most had received one or more lines of systemic therapy; 44% had been treated for ≥ one previous locoregional recurrences. At start of re-RT + HT there was no macroscopically detectable tumour following surgery (96%) or chemotherapy (CT). Re-RT typically consisted of eight fractions of 4Gy, given twice weekly. Hyperthermia was added once a week. Results: After a median follow up of 64.2 months, three-year survival was 66%. Three- and five-year local control rates were 78% and 65%. Acute grade 3 toxicity occurred in 32% of patients. The risk of late ≥ grade 3 toxicity was 40% after three years. Time interval to the current recurrence was found to be most predictive for local control in univariate and multivariate analysis. The extensiveness of current surgery was the most relevant treatment related factor associated with toxicity. Conclusions: For patients experiencing local recurrence in a previously radiated area, re-irradiation plus hyperthermia following minimisation of tumour burden leads to a high rate of local control, albeit with significant toxicity. The latter might be reduced by a more fractionated re-RT schedule.
The Journal of Urology | 2015
Elisabeth D. Geijsen; Theo M. de Reijke; Caro C.E. Koning; Paul J. Zum Vörde Sive Vörding; Jean de la Rosette; Coen R. N. Rasch; Rob M. van Os; J. Crezee
PURPOSEnDespite intravesical therapy with immunotherapy or chemotherapy intermediate and high risk nonmuscle invasive bladder cancer is associated with a high risk of recurrence and progression to muscle invasive bladder carcinoma. While intravesical hyperthermia combined with mitomycin C has proved effective to treat nonmuscle invasive bladder cancer, there is less experience with invasive regional 70 MHz hyperthermia and mitomycin C. Therefore, we examined the safety and feasibility of this treatment combination for intermediate and high risk nonmuscle invasive bladder cancer.nnnMATERIALS AND METHODSnBetween 2009 and 2011, 20 patients with intermediate and high risk nonmuscle invasive bladder cancer were treated with intravesical mitomycin C (40 mg) combined with regional hyperthermia. Treatment consisted of 6 weekly sessions followed by a maintenance period of 1 year with 1 hyperthermia-mitomycin C session every 3 months. Regional hyperthermia was administered using a 70 MHz phased array system with 4 antennas. Toxicity was scored using CTC (Common Toxicity Criteria) 3.0.nnnRESULTSnThe records of 18 of 20 patients could be analyzed. Median followup was 46 months. Of the 18 patients 15 (83%) completed the induction period of 6 treatments. Four patients (22%) discontinued treatment because of physical complaints without exceeding grade 2 toxicity. Toxicity scored according to CTC 3.0 was limited to grade 1 in 43% of cases and grade 2 in 14%. Mean T90 and T50 bladder temperatures were 40.6C and 41.6C, respectively. The 24-month recurrence-free survival rate was 78%.nnnCONCLUSIONSnTreatment with regional hyperthermia combined with mitomycin C in patients with intermediate and high risk nonmuscle invasive bladder cancer is feasible with low toxicity and excellent bladder temperatures.
Radiotherapy and Oncology | 2015
S. Oldenborg; V. Griesdoorn; Rob M. van Os; Yoka H. Kusumanto; Bing Oei; Jack Venselaar; Paul J. Zum Vörde Sive Vörding; Martijn W. Heymans; M.W. Kolff; Coen R. N. Rasch; Hans Crezee; Geertjan van Tienhoven
BACKGROUND/PURPOSEnTreatment options for irresectable locoregional recurrent breast cancer in previously irradiated area are limited. Hyperthermia, elevating tumor temperature to 40-45°C, sensitizes radio-and-chemotherapy. Four hundred and fourteen patients treated with reirradiation+hyperthermia (reRT+HT) in the AMC(n=301) and the BVI(n=113), from 1982 to 2005 were retrospectively analyzed for treatment response, locoregional control (LC) and prognostic factors for LC and toxicity.nnnPATIENTS/METHODSnAll patients received previous irradiation (median 50 Gy). reRT consisted of 8 × 4 Gy-2/week (AMC) or 12 × 3 Gy-4/week (BVI). Hyperthermia was added once (AMC)/twice (BVI) a week.nnnRESULTSnOverall clinical response rate was 86%. The 3-year LC rate was 25%. The number of recurrence episodes, distant metastases (DM), tumor site, tumor size, time to recurrence and treatment year were significant for LC. Acute ⩾ grade 3 toxicity occurred in 24% of patients. Actuarial late ⩾ grade 3 toxicity was 23% at 3-years. In multivariable analysis reRT fraction dose was significantly related to late ⩾ grade 3 toxicity.nnnCONCLUSIONnreRT+HT is an effective curative and palliative treatment option for patients with irresectable locoregional recurrent breast cancer in previously irradiated area. Early referral, treatment of chest wall recurrences ⩽ 5 cm in the absence of distant metastases, provided the highest local control rates. The cumulative effects of past and present treatments should be accounted for by adjusting treatment protocol to minimize toxicity.
International Journal of Radiation Oncology Biology Physics | 2013
Irma W.E.M. van Dijk; Mathilde C. Cardous-Ubbink; Helena J. van der Pal; Richard C. Heinen; Flora E. van Leeuwen; Foppe Oldenburger; Rob M. van Os; Cécile M. Ronckers; Antoinette Y. N. Schouten-van Meeteren; Huib N. Caron; Caro C.E. Koning; Leontien C.M. Kremer
PURPOSEnTo evaluate the prevalence and severity of clinical adverse events (AEs) and treatment-related risk factors in childhood cancer survivors treated with cranial radiation therapy (CRT), with the aim of assessing dose-effect relationships.nnnMETHODS AND MATERIALSnThe retrospective study cohort consisted of 1362 Dutch childhood cancer survivors, of whom 285 were treated with CRT delivered as brain irradiation (BI), as part of craniospinal irradiation (CSI), and as total body irradiation (TBI). Individual CRT doses were converted into the equivalent dose in 2-Gy fractions (EQD(2)). Survivors had received their diagnoses between 1966 and 1996 and survived at least 5 years after diagnosis. A complete inventory of Common Terminology Criteria for Adverse Events grade 3.0 AEs was available from our hospital-based late-effect follow-up program. We used multivariable logistic and Cox regression analyses to examine the EQD(2) in relation to the prevalence and severity of AEs, correcting for sex, age at diagnosis, follow-up time, and the treatment-related risk factors surgery and chemotherapy.nnnRESULTSnThere was a high prevalence of AEs in the CRT group; over 80% of survivors had more than 1 AE, and almost half had at least 5 AEs, both representing significant increases in number of AEs compared with survivors not treated with CRT. Additionally, the proportion of severe, life-threatening, or disabling AEs was significantly higher in the CRT group. The most frequent AEs were alopecia and cognitive, endocrine, metabolic, and neurologic events. Using the EQD(2), we found significant dose-effect relationships for these and other AEs.nnnCONCLUSIONnOur results confirm that CRT increases the prevalence and severity of AEs in childhood cancer survivors. Furthermore, analyzing dose-effect relationships with the cumulative EQD(2) instead of total physical dose connects the knowledge from radiation therapy and radiobiology with the clinical experience.
Radiation Oncology | 2007
Apollonia L.J. Uitterhoeve; Mia G.J. Koolen; Rob M. van Os; Kees Koedooder; Marlou van de Kar; Bradley R. Pieters; Caro C.E. Koning
BackgroundResults of high-dose chemo-radiotherapy (CRT), using the treatment schedules of EORTC study 08972/22973 or radiotherapy (RT) alone were analyzed among all patients (pts) with Non Small Cell Lung Cancer (NSCLC) treated with curative intent in our department from 1995–2004.MaterialIncluded are 131 pts with medically inoperable or with irresectable NSCLC (TNM stage I:15 pts, IIB:15 pts, IIIA:57 pts, IIIB:43 pts, X:1 pt).TreatmentGroup I: Concomitant CRT: 66 Gy/2.75 Gy/24 fractions (fx)/33 days combined with daily administration of cisplatin 6 mg/m2: 56 pts (standard).Group II: Sequential CRT: two courses of a 21-day schedule of chemotherapy (gemcitabin 1250 mg/m2 d1, cisplatin 75 mg/m2 d2) followed by 66 Gy/2.75 Gy/24 fx/33 days without daily cisplatin: 26 pts.Group III: RT: 66 Gy/2.75 Gy/24 fx/33 days or 60 Gy/3 Gy/20 fx/26 days: 49 pts.ResultsThe 1, 2, and 5 year actuarial overall survival (OS) were 46%, 24%, and 15%, respectively.At multivariate analysis the only factor with a significantly positive influence on OS was treatment with chemo-radiation (P = 0.024) (1-, 2-, and 5-yr OS 56%, 30% and 22% respectively). The incidence of local recurrence was 36%, the incidence of distant metastases 46%.Late complications grade 3 were seen in 21 pts and grade 4 in 4 patients. One patient had a lethal complication (oesophageal). For 32 patients insufficient data were available to assess late complications.ConclusionIn this study we were able to reproduce the results of EORTC trial 08972/22973 in a non-selected patient population outside of the setting of a randomised trial. Radiotherapy (66 Gy/24 fx/33 days) combined with either concomitant daily low dose cisplatin or with two neo-adjuvant courses of gemcitabin and cisplatin are effective treatments for patients with locally advanced Non-Small Cell Lung Cancer. The concomitant schedule is also suitable for elderly people with co-morbidity.
Gynecologic Oncology | 2014
Raquel Dávila Fajardo; Rob M. van Os; Marrije R. Buist; Lon Uitterhoeve; Anneke M. Westermann; Gemma G. Kenter; Coen R. N. Rasch; Lukas J.A. Stalpers
OBJECTIVEnThe aim of this study is to investigate the impact of treatment policy changes in cervical cancer patients treated with adjuvant (chemo) radiotherapy.nnnMETHODSnBetween 1970 and 2007, 292 patients received adjuvant radiotherapy after a radical hysterectomy with pelvic lymphadenectomy for early stage cervical carcinoma. All patients received pelvic radiotherapy (40 Gy-46 Gy in 1.8 Gy-2 Gy/fraction). Vaginal vault brachytherapy boost (10-14 Gy) was increasingly used for patients with high-risk factors, and since 1993 systematically applied in patients with at least 2 of the 3 risk factors: adenocarcinoma, nodal involvement and parametrial invasion. Cisplatin-based chemotherapy was introduced in this group of patients from 2000.nnnRESULTSnThe 5-year cumulative risk of local recurrence (CRLR) was 13% (95%CI 9%-17%), resulting in an overall 5-year survival (OS) of 78% (95%CI 83%-73%). Since 1970, the OR for the 5-year locoregional recurrence risk (LRR) decreased from 2.5 to 1.15 (linear-OR=-0.02/year). The OR for the 5-year mortality risk reduced from 2.2 in 1970 to 1.0 in 2007 (linear-OR=-0.03/year). The largest risk reductions were observed before 1990 with a minor rise after 2002. The risk of severe late toxicity reduced from 1.8% to 1.5% (linear-OR=-0.03/year). The addition of concomitant adjuvant chemotherapy since 2000 may have benefited a subgroup of patients with squamous cell carcinoma, but not the patients with adenocarcinoma, and after introduction of chemotherapy the risk of severe late toxicity tripled from 2% to 7%.nnnCONCLUSIONnSince 1970, tumour recurrence risk and mortality have decreased, as radiation dose increased. The potential benefit of concomitant adjuvant chemotherapy could not be demonstrated in this nonrandomized study.