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Featured researches published by Alexander A.W. Peters.


International Journal of Gynecological Cancer | 2002

A nerve‐sparing radical hysterectomy: guidelines and feasibility in Western patients

J.B.M.Z. Trimbos; Cornelis P. Maas; Marco C. DeRuiter; Alexander A.W. Peters; G.G. Kenter

Surgical damage to the pelvic autonomic nerves during radical hysterectomy is thought to be responsible for considerable morbidity, i.e., impaired bladder function, defecation problems, and sexual dysfunction. Previous anatomical studies and detailed study of surgical techniques in various Japanese oncology centers demonstrated that the anatomy of the pelvic autonomic nerve plexus permits a systematic surgical approach to preserve these nerves during radical hysterectomy without compromising radicality. We introduced elements of the Japanese nerve-preserving techniques and carried out a feasibility study in ten consecutive Dutch patients. The technique involved three steps: first, the identification and preservation of the hypogastric nerve in a loose tissue sheath underneath the ureter and lateral to the sacro-uterine ligaments; second, the inferior hypogastric plexus in the parametrium is lateralized and avoided during parametrial transsection; third, the most distal part of the inferior hypogastric plexus is preserved during the dissection of the posterior part of the vesico-uterine ligament. The clinical study showed that the procedure is feasible and safe, except possibly when used with very obese patients and patients with broad, bulky tumors. Surgical preservation of the pelvic autonomic nerves in radical hysterectomy deserves consideration in the quest to improve both cure and quality of life in cervical cancer patients.


Clinical Cancer Research | 2007

High human papillomavirus oncogene mRNA expression and not viral DNA load is associated with poor prognosis in cervical cancer patients

Marjon A. de Boer; Ekaterina S. Jordanova; Gemma G. Kenter; Alexander A.W. Peters; Willem E. Corver; J. Baptist Trimbos; Gert Jan Fleuren

Purpose: Cervical cancer is now known to be caused by infection with an oncogenic type of the human papillomavirus (HPV). However, little is known about the continued role of HPV once cancer has been established. Here, we describe the quantitative relation between HPV DNA copy number and mRNA expression of the viral oncogenes (E6 and E7) and the prognostic value of both measures in cervical cancer patients. Experimental Design: We studied the number of viral DNA copies and the level of HPV E6/E7 mRNA expression in 75 HPV 16–positive or HPV 18–positive International Federation of Gynecology and Obstetrics stage Ib and IIa cervical cancer patients. Measurements were done with quantitative PCR. DNA copy number analysis was done on pure tumor cell samples enriched with flow sorting. mRNA expression data were compensated for the percentage of tumor cells included. Results: The number of viral DNA copies was not predictive of survival in cervical cancer patients. In contrast, high HPV E6/E7 mRNA expression was strongly related to an unfavorable prognosis (P = 0.006). In a multivariate Cox model for overall survival, including all known prognostic variables and stratified for HPV type, the level of E6/E7 mRNA expression was an independent prognostic indicator, second only to lymph node status. No correlation was observed between DNA copy number and the level of HPV E6/E7 mRNA expression, which reflects that not all DNA copies are equally transcriptionally active. Conclusions: Cervical cancer patients with high HPV E6/E7 oncogene mRNA expression have a worse survival independently from established prognostic factors.


International Journal of Gynecological Cancer | 2011

Optimization of near-infrared fluorescent sentinel lymph node mapping in cervical cancer patients.

Joost R. van der Vorst; Merlijn Hutteman; Katja N. Gaarenstroom; Alexander A.W. Peters; J. Sven D. Mieog; Boudewijn E. Schaafsma; Peter J. K. Kuppen; John V. Frangioni; Cornelis J. H. van de Velde; Alexander L. Vahrmeijer

Objective: In early cervical cancer, a total pelvic lymphadenectomy is the standard of care, even though most patients have negative nodes and thus undergo lymphadenectomy unnecessarily. Although the value of sentinel lymph node (SLN) mapping in early-stage cervical cancer has not yet been established, near-infrared (NIR) fluorescence imaging is a promising technique to perform this procedure. Near-infrared fluorescence imaging is based on invisible NIR light and can provide high sensitivity, high-resolution, and real-time image guidance during surgery. Methods: Clinical trial subjects were 9 consecutive cervical cancer patients undergoing total pelvic lymphadenectomy. Before surgery, 1.6 mL of indocyanine green adsorbed to human serum albumin (ICG:HSA) was injected transvaginally and submucosally in 4 quadrants around the tumor. Patients were allocated to 500-, 750-, or 1000-&mgr;M ICG:HSA concentration groups. The Mini-FLARE imaging system was used for NIR fluorescence detection and quantitation. Results: Sentinel lymph nodes were identified in all 9 patients. An average of 3.4 ± 1.2 SLNs was identified per patient. No differences in signal to background of the SLNs between the 500-, 750-, and 1000-&mgr;M dose groups were found (P = 0.73). In 2 patients, tumor-positive lymph nodes were found. In both patients, tumor-positive lymph nodes confirmed by pathology were also NIR fluorescent. Conclusions: This study demonstrated preliminary feasibility to successfully detect SLNs in cervical cancer patients using ICG:HSA and the Mini-FLARE imaging system. When considering safety, cost-effectiveness, and pharmacy preferences, an ICG:HSA concentration of 500 &mgr;M was optimal for SLN mapping in cervical cancer patients.


International Journal of Gynecological Cancer | 2009

Nerve-sparing radical hysterectomy: local recurrence rate, feasibility, and safety in cervical cancer patients stage IA to IIA.

Sabrina A. H. M. van den Tillaart; Gemma G. Kenter; Alexander A.W. Peters; Friedo W. Dekker; Katja N. Gaarenstroom; G.J. Fleuren; J. Baptist Trimbos

Objective: To clarify the debate about the possible threat of sparing the pelvic autonomic nerves in radical hysterectomy for cervical cancer to radicality, comparative studies of nerve-sparing and conventional surgery are necessary. The aim of his study was to analyze and compare local recurrence rate, feasibility, and safety of nerve-sparing and non-nerve-sparing radical hysterectomy. Methods: In a cohort study with 2 years of follow-up, 246 patients with cervical cancer of stages IA to IIA were analyzed: 124 in the non-nerve-sparing group (1994-1999) and 122 in the group where nerve-sparing was the intention-to-treat (2001-2005). Local recurrence rate, local recurrence-free survival, feasibility, and safety were analyzed and compared. Results: The clinical characteristics of the treatment groups were comparable. Sparing the nerves unilaterally or bilaterally was possible in 80% of cases of the nerve-sparing group. Local recurrence rates in the non-nerve-sparing (4.9%) and nerve-sparing (8.3%) group were not significantly different. Mean local recurrence-free survival within 2 years were 22.7 and 22.0 months, respectively. Univariate and multivariate regression analyses showed that nerve-sparing treatment was not a significant prognostic factor for local recurrence. With respect to perioperative and postoperative parameters, operating time and blood loss were less in the nerve-sparing group and mortality was equal (1 patient); the postoperative course of the nerve-sparing group was similar to the state-of-the-art of conventional radical hysterectomy. Conclusions: On the basis of the results of our study, we consider the nerve-sparing technique for cervical cancer stages IA to IIA feasible and safe.


Gynecologic Oncology | 2012

Randomized comparison of near-infrared fluorescence lymphatic tracers for sentinel lymph node mapping of cervical cancer.

Boudewijn E. Schaafsma; Joost R. van der Vorst; Katja N. Gaarenstroom; Alexander A.W. Peters; F.P.R. Verbeek; Cornelis D. de Kroon; J. Baptist Trimbos; Mariette I.E. van Poelgeest; John V. Frangioni; Cornelis J. H. van de Velde; Alexander L. Vahrmeijer

OBJECTIVE Near-infrared fluorescence imaging using indocyanine green (ICG) has recently been introduced as a novel technique for sentinel lymph node (SLN) mapping in early-stage cervical cancer. Although preclinical research has shown that ICG adsorbed to human serum albumin (ICG:HSA) improves its performance, the need for HSA has not yet been confirmed in cervical cancer patients. The current randomized study aims to determine whether ICG:HSA offers advantages over using ICG alone. METHODS Eighteen consecutive early-stage cervical cancer patients scheduled to undergo pelvic lymphadenectomy were included. Prior to surgery, 1.6 mL of 500 μM ICG:HSA or 500 μM ICG alone was injected transvaginally in 4 quadrants around the tumor. The Mini-FLARE imaging system was used for intraoperative NIR fluorescence detection and quantitation. RESULTS SLNs were identified intraoperatively in 78% of the patients. Patient and tumor characteristics were equally distributed over both treatment groups. No significant difference in signal-to-background ratio (9.3 vs. 10.1, P=.72) or average number of detected SLNs (2.9 vs 2.7, P=.84) was found between the ICG:HSA group and the ICG alone group, respectively. CONCLUSIONS In conclusion, this double-blind, randomized trial showed no advantage of ICG:HSA over ICG alone for the SLN procedure in early-stage cervical cancer. Further optimization is required to improve the intraoperative detection rate.


PLOS ONE | 2015

The Value of Intraoperative Near-Infrared Fluorescence Imaging Based on Enhanced Permeability and Retention of Indocyanine Green: Feasibility and False-Positives in Ovarian Cancer.

Quirijn R.J.G. Tummers; Charlotte E.S. Hoogstins; Alexander A.W. Peters; Cor D. de Kroon; J. Baptist Trimbos; Cornelis J. H. van de Velde; John V. Frangioni; Alexander L. Vahrmeijer; Katja N. Gaarenstroom

Objective In ovarian cancer, two of the most important prognostic factors for survival are completeness of staging and completeness of cytoreductive surgery. Therefore, intra-operative visualization of tumor lesions is of great importance. Preclinical data already demonstrated tumor visualization in a mouse-model using near-infrared (NIR) fluorescence imaging and indocyanine green (ICG) as a result of enhanced permeability and retention (EPR). The aim of this study was to determine feasibility of intraoperative ovarian cancer metastases imaging using NIR fluorescence imaging and ICG in a clinical setting. Methods Ten patients suspected of ovarian cancer scheduled for staging or cytoreductive surgery were included. Patients received 20 mg ICG intravenously after opening the abdominal cavity. The mini-FLARE NIR fluorescence imaging system was used to detect NIR fluorescent lesions. Results 6 out of 10 patients had malignant disease of the ovary or fallopian tube, of which 2 had metastatic disease outside the pelvis. Eight metastatic lesions were detected in these 2 patients, which were all NIR fluorescent. However, 13 non-malignant lesions were also NIR fluorescent, resulting in a false-positive rate of 62%. There was no significant difference in tumor-to-background ratio between malignant and benign lesions (2.0 vs 2.0; P=0.99). Conclusions This is the first clinical trial demonstrating intraoperative detection of ovarian cancer metastases using NIR fluorescence imaging and ICG. Despite detection of all malignant lesions, a high false-positive rate was observed. Therefore, NIR fluorescence imaging using ICG based on the EPR effect is not satisfactory for the detection of ovarian cancer metastases. The need for tumor-specific intraoperative agents remains. Trial Registration ISRCTN Registry ISRCTN16945066


Vaccine | 2011

Parental acceptance of human papillomavirus (HPV) vaccination in Indonesia: A cross-sectional study

L. Jaspers; S. Budiningsih; R. Wolterbeek; F.C. Henderson; Alexander A.W. Peters

BACKGROUND Cervical cancer ranks the second most frequent cancer in Indonesian women. In Indonesia, human papillomavirus (HPV) vaccine acceptance has not been studied before. OBJECTIVE To determine parental HPV vaccine acceptance in Indonesia, and factors that influence their decision. Factors include sociodemographic factors, knowledge of HPV, HPV vaccination and cervical cancer, health beliefs about cervical cancer, and attitudes towards vaccination in general. METHODS 746 parents, with at least 1 daughter aged 0-14, were interviewed using questionnaires based on published and adjusted interviews. Interviews were done in sub district public health centers, general governmental hospitals, and via house-visits, in 5 Indonesian provinces. RESULTS Parental HPV vaccine acceptance was 96.1%. Logistic regression revealed that age, beliefs regarding cervical cancer, and attitudes towards vaccination in general were significantly associated with HPV vaccine acceptance. Of the participants, 66.0%, 16.6%, and 15.8% had heard about cervical cancer, HPV, and HPV vaccination respectively. The mean total knowledge score was 1.91(Standard Deviation 2.31) on a 0-8 scale. Health beliefs about cervical cancer and attitudes towards vaccination in general were positive. Participants named the high cost of the vaccine, fear for side-effects, and chosen vaccination locations as possible barriers towards HPV vaccine implementation. DISCUSSION Parental HPV vaccine acceptance is high, but knowledge about HPV and cervical cancer is low. During HPV vaccination programs, focus should not only be on providing information, but also on existing beliefs and attitudes towards cervical cancer and vaccination in general. If HPV vaccination programs were to be implemented in Indonesia, the indicated barriers should be taken into account.


British Journal of Cancer | 2008

Prevalence of human papillomavirus in Indonesia: a population-based study in three regions

J.N.I. Vet; M. A. de Boer; B.E. van den Akker; Budiningsih Siregar; Lisnawati; S Budiningsih; D Tyasmorowati; Moestikaningsih; Santoso Cornain; Alexander A.W. Peters; Gert Jan Fleuren

Cervical cancer is the most common cancer among women in the Indonesian population, yet little is known about the prevalence of human papillomavirus (HPV). We investigated age-specific prevalence of HPV types and possible risk factors of HPV positivity in a population-based sample of 2686 women, aged 15–70 years, in Jakarta, Tasikmalaya, and Bali, Indonesia. The overall HPV prevalence was 11.4%, age-standardized to the world standard population 11.6%. The most prevalent types found were HPV 52, HPV 16, HPV 18, and HPV 39, respectively, 23.2, 18.0, 16.1, and 11.8% of the high-risk HPV types. In 20.7% of infections, multiple types were involved. Different age-specific prevalence patterns were seen: overall high in Jakarta, and in Tasikmalaya, and declining with age in Bali. The number of marriages was most associated with HPV positivity (OR 1.81 95% CI 1.31–2.51)). Remarkably, in Indonesia HPV 16 and HPV 18 are equally common in the general population, as they are in cervical cancer. HPV 52 was the most prevalent type in the general population, suggesting that this type should be included when prophylactic HPV vaccination is introduced in Indonesia.


European Journal of Obstetrics & Gynecology and Reproductive Biology | 1996

Pain relief during and following outpatient curettage and hysterosalpingography: a double blind study to compare the efficacy and safety of Tramadol versus Naproxen

Alexander A.W. Peters; E.H. Witte; A.C.H. Damen; J.P. Holm; A.C. Drogendijk; E.A. vd Velde; J.B. Trimbos

OBJECTIVE To compare the analgetic efficacy and side-effects of Naproxen and Tramadol following the outpatient VABRA aspiration or hysterosalpingography. SETTING Ninety-one patients from the gynaecology clinics of two university hospitals and one municipal-teaching hospital. DESIGN Multicentre double blind randomized clinical trial. Computerised randomisation, stratification per-centre. METHODS Semiquantitative assessment of the two drugs was performed by the patient and the gynaecologist using a 1- to 6-point scale. Pain, stress and well-being was scored by the patient using the visual analog scale (VAS) and the verbal description scale (VDS), ranging from 0 (good) to 100 (bad). Side-effects during the first 24 h postoperatively were recorded by the patient in a diary. RESULTS The analgetic efficacy (pain, stress and well-being) of Naproxen and Tramadol was identical. Subjective assessment by the patient and the doctor also revealed no differences between Naproxen and Tramadol. Side-effects of Tramadol, however, were significantly more severe than those of Naproxen and this phenomenon was responsible for a lower ability to proceed with normal activities in the Tramadol group. CONCLUSION Tramadol is a good alternative for Naproxen at outpatient VABRA or HSG procedures when Naproxen is contra-indicated.


European Journal of Obstetrics & Gynecology and Reproductive Biology | 1993

A comparison of pefloxacin/metronidazole and doxycycline/metronidazole in the treatment of laparoscopically confirmed acute pelvic inflammatory disease

E.H. Witte; Alexander A.W. Peters; I.B.C. Smit; M.C.G.J. van der Linden; R.P. Mouton; J.W.M. van der Meer; E.J.M. van Erp

A double-blind, randomised study was conducted to compare the efficacy and safety of a combination of pefloxacin and metronidazole versus doxycycline and metronidazole in patients with pelvic inflammatory disease (PID). The clinical diagnosis had to be confirmed by laparoscopy before patients were included. Of the 74 patients who fulfilled the clinical criteria for PID, laparoscopy confirmed the diagnosis in only 40 patients (54%). The microorganism most frequently found as causative pathogen was Chlamydia trachomatis. Both treatment groups showed a good response to the study-medication. At discharge 9 patients in the pefloxacin group (45%) were cured and 10 patients (50%) had improved. In the doxycycline group 7 patients (35%) were cured and 10 patients (50%) had improved. Obviously pefloxacin/metronidazole and doxycycline/metronidazole are equally effective in the treatment of PID.

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Gert Jan Fleuren

Leiden University Medical Center

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Katja N. Gaarenstroom

Leiden University Medical Center

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Alexander L. Vahrmeijer

Leiden University Medical Center

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Vivian M. Spaans

Leiden University Medical Center

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John V. Frangioni

Beth Israel Deaconess Medical Center

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Boudewijn E. Schaafsma

Leiden University Medical Center

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G.G. Kenter

Leiden University Medical Center

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