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Dive into the research topics where Claus A. Kristensen is active.

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Featured researches published by Claus A. Kristensen.


Oral Oncology | 2011

Salivary gland carcinoma in Denmark 1990–2005: A national study of incidence, site and histology. Results of the Danish Head and Neck Cancer Group (DAHANCA)

Kristine Bjørndal; Annelise Krogdahl; Marianne Hamilton Therkildsen; Jens Overgaard; Jørgen Johansen; Claus A. Kristensen; Preben Homøe; Christian Hjort Sørensen; Elo Andersen; Troels Bundgaard; Hanne Primdahl; Karin Lambertsen; Lisbeth Juhler Andersen; Christian Godballe

To describe the incidence, site and histology (WHO 2005) of salivary gland carcinomas in Denmark. Nine hundred and eighty-three patients diagnosed from 1990 to 2005 were identified from three nation-wide registries. The associated clinical data were retrospectively retrieved from patient medical records. Histological revision was performed in 886 cases (90%). Based on histological revision, 31 patients (3%) were excluded from the study leaving 952 for epidemiological analysis. The mean crude incidence in Denmark was 1.1/100,000/year. The male vs. female ratio was 0.97 and the median age was 62 years. The parotid gland was the most common site (52.5%) followed by the minor salivary glands of the oral cavity (26.3%). The most frequent histological subtypes were adenoid cystic carcinoma (25.2%), mucoepidermoid carcinoma (16.9%), adenocarcinoma NOS (12.2%) and acinic cell carcinoma (10.2%). The revision process changed the histological diagnosis in 121 out of 886 cases (14%). The incidence of salivary gland carcinoma in Denmark is higher than previously reported. More than half of salivary gland carcinomas are located in the parotid gland with adenoid cystic carcinoma being the most frequent subtype. Histological classification of salivary gland carcinomas is difficult and evaluation by dedicated pathology specialists might be essential for optimal diagnosis and treatment.


Radiotherapy and Oncology | 2009

Pulmonary toxicity following IMRT after extrapleural pneumonectomy for malignant pleural mesothelioma

Claus A. Kristensen; Trine Juhler Nøttrup; Anne Kiil Berthelsen; Flemming Kjær-Kristoffersen; Jesper Ravn; Jens Benn Sørensen; S.A. Engelholm

BACKGROUND AND PURPOSE The combination of chemotherapy, surgery, and radiotherapy has improved the prognosis for patients with malignant pleural mesothelioma (MPM). Intensity-modulated radiotherapy (IMRT) has allowed for an increase in dose to the pleural cavity and a reduction in radiation doses to organs at risk. The present study reports and analyses the incidence of fatal pulmonary toxicity in patients treated at Rigshospitalet, Copenhagen. MATERIALS AND METHODS Twenty-six patients were treated with induction chemotherapy followed by extrapleural pneumonectomy and IMRT between April 2003 and April 2006. The entire preoperative pleural surface area was treated to 50 Gy and areas with residual disease or close surgical margins were treated to 60 Gy in 30 fractions. RESULTS The main toxicities were nausea, vomiting, esophagitis, dyspnea, and thrombocytopenia. One patient died from an intracranial hemorrhage during severe thrombocytopenia. Four patients (15%) experienced grade 5 lung toxicity, i.e. pneumonitis 19-40 days after the completion of radiotherapy. Patients with pneumonitis had a significantly larger lung volume fraction receiving 10 Gy or more (V10) (median: 60.3%, range 56.4-83.2%) compared to patients without pneumonitis (median: 52.6%, range: 25.6-80.3%) (p=0.02). Mean lung dose (MLD) was also significantly higher in patients who developed pneumonitis (median 13.9 Gy, range: 13.6-14.2 Gy) than in patients who did not (median=12.4 Gy, range: 8.4-15.4 Gy) (p=0.04). CONCLUSIONS Significant differences in MLD and V10 for patients with fatal pulmonary toxicity compared to patients without fatal lung toxicity have been demonstrated. Based on the presented data local lung dose constraints have been modified in order to avoid unacceptable toxicity.


Acta Oncologica | 2010

Carcinoma of the nasal cavity and paranasal sinuses in Denmark 1995-2004

Christian Thorup; Lars Sebbesen; Hella Danø; Michael Leetmaa; Mette Andersen; Christian von Buchwald; Claus A. Kristensen; Jens Bentzen; Christian Godballe; Jørgen Johansen; Cai Grau

Abstract Objective. To evaluate the treatment outcome for sino-nasal carcinomas in Denmark from 1995–2004 and compare the results to the previous Danish survey covering 1982–1991. Design. Retrospective follow-up. Materials and methods. In the five Danish head and neck oncology centres, charts of all consecutive patients with sino-nasal carcinomas were reviewed and data extracted to a common database. Altogether 242 patients from the period 1995–2004 were identified. Of these 162 (67%) were male and 80 (33%) female. Histologies included squamous cell carcinoma (55%), adenocarcinoma (28.5%), adenoid-cystic carcinoma (5.0%), undifferentiated carcinoma (4.5%), transitiocellular carcinoma (1.7%), mucoepidermoid carcinoma (0.8%), neuroendocrine carcinoma (2.5%), small cell carcinomas (1.2%) and carcinomas not otherwise specified (0.8%). Treatments included radiotherapy alone 79 (33%), surgery alone 29 (12%), combined surgery and radiotherapy 96 (40%), palliative/no treatment 38 (16%). A total of 204 (86%) patients were treated with curative intent. Results. Of the 204 patients treated with curative intent, 94 (46%) relapsed. Most failures were in T-site (63, 30%). N-site failures were 10 (5%) and M-site failures six (3%). Failure occurring in T+N-site, T+M-site, N+M-site and T+N+M-site were seven (3%), two (1%), one (0.5%) and five (3%) respectively. The 5-year actuarial local, nodal and loco-regional control rates were 55±4%, 86±3%, 49±4%, respectively. The overall 5-year actuarial survival rate for the entire cohort was 47±3%, and the corresponding cancer-specific 5-year actuarial survival rate was 57±3%. Female gender, nasal cavity tumour, adenocarcinoma and low clinical stage were significant positive prognostic factors in univariate analysis. A Cox multivariate analysis showed that only tumour site and clinical stage were independent significant prognostic factors. Conclusion. The current series has confirmed stage and tumour site as independent prognostic factors. Compared to the previous Danish survey covering the period 1982–1991, the overall survival and cancer-specific survival rates have improved significantly.


European Journal of Cancer | 2013

Waiting times for diagnosis and treatment of head and neck cancer in Denmark in 2010 compared to 1992 and 2002

Nina Munk Lyhne; A. Christensen; Mikkel Christian Alanin; Mie Topholm Bruun; Tove Holme Jung; Mikkel A. Bruhn; Janus Bo Bechmann Jespersen; Claus A. Kristensen; Elo Andersen; Christian Godballe; Christian von Buchwald; Troels Bundgaard; Jørgen Johansen; Karin Lambertsen; Hanne Primdahl; Kasper Toustrup; Jens Ahm Sørensen; Jens Overgaard; Cai Grau

BACKGROUND AND AIM Significant tumour progression was observed during waiting time for treatment of head and neck cancer. To reduce waiting times, a Danish national policy of fast track accelerated clinical pathways was introduced in 2007. This study describes changes in waiting time and the potential influence of fast track by comparing waiting times in 2010 to 2002 and 1992. METHODS Charts of all new patients diagnosed with squamous cell carcinoma of the oral cavity, pharynx and larynx at the five Danish head and neck oncology centres from January to April 2010 (n=253) were reviewed and compared to similar data from 2002 (n=211) and 1992 (n=168). RESULTS The median time to diagnosis was 13 days (2010) versus 17 days (2002; p<0.001) and 20 days (1992; p<0.001). Median days from diagnosis to treatment start were 25 (2010) versus 47 (2002; p<0.001) and 31 (1992; p<0.001). Total pre-treatment time was median 41 days in 2010 versus 69 days (2002) (p<0.001) and 50 days (1992; p<0.001). Significantly more diagnostic imaging was done in 2010 compared to 2002 and 1992. When compared to current fast track standards the adherence to diagnosis improved slightly from 47% (1992) to 51% (2002) and 64% (2010); waiting time for radiotherapy was within standards for 7%, 1% and 22% of cases, respectively; waiting time for surgery was within standards for 17%, 22% and 48%, respectively. CONCLUSION The study showed a significant reduction in delay of diagnosis and treatment of head and neck cancer in 2010, but still less than half of all patients start treatment within the current standards.


Acta Oncologica | 2007

Nasopharyngeal carcinoma. Treatment planning with IMRT and 3D conformal radiotherapy

Claus A. Kristensen; Flemming Kjær-Kristoffersen; Wendy Sapru; Anne Kiil Berthelsen; Annika Loft; Lena Specht

The study was undertaken in order to compare dose plans for intensity-modulated radiotherapy (IMRT) with 3D conformal radiotherapy (3D-CRT) dose plans in patients with nasopharyngeal carcinoma (NPC). Clinical data from 20 consecutive patients treated with IMRT are presented. For 11 patients 3D-CRT plans were made and compared to the IMRT plans with respect to doses to the planning target volumes (PTVs) and to organs at risk (OARs). For comparison of the conformation of dose to defined target volumes the conformity index (CI) was used. Target volume coverage and critical organ protection were significantly improved with IMRT compared to 3D-CRT. One-year loco-regional control, distant metastasis-free survival, and overall survival were 79%, 72%, and 80%. Two patients have had recurrence in the clinical target volume (CTV) only and seven patients have relapsed in distant organs and/or in head-and-neck areas outside the target areas. The study confirms that IMRT is superior to 3D-CRT in the treatment of NPC. As locoregional control of NPC improves we are facing an increasing number of recurrences outside the irradiated area.


Oral Oncology | 2012

Salivary gland carcinoma in Denmark 1990-2005: outcome and prognostic factors. Results of the Danish Head and Neck Cancer Group (DAHANCA).

Kristine Bjørndal; Annelise Krogdahl; Marianne Hamilton Therkildsen; Jens Overgaard; Jørgen Johansen; Claus A. Kristensen; Preben Homøe; Christian Hjort Sørensen; Elo Andersen; Troels Bundgaard; Hanne Primdahl; Karin Lambertsen; Lisbeth Juhler Andersen; Christian Godballe

To describe outcome and prognostic factors in a national Danish series of patients treated for salivary gland carcinoma. From three Danish nation-wide registries and supplementary patient records, 871 patients diagnosed with primary major or minor salivary gland carcinoma in the period from 1990 to 2005 were identified. A total of 796 (91%) histological specimens were revised according to the WHO 2005 classification. The median follow-up time was 78 months. Three hundred and thirty-four patients (38%) experienced recurrence. Crude survival, disease-specific survival and recurrence-free survival after 5 and 10 years were 66%, 76%, 64% and 51%, 69%, 58%, respectively. In multivariate analysis age, latency, stage, microscopic margins, vascular invasion and histological grade were all independent prognostic factors with regards to crude and disease-specific survival. Stage, microscopic margins, vascular invasion and histological grade were independent prognostic factors for recurrence-free survival. Age over 61 years, latency under 8 months, stage 3+4 disease, involved or close microscopic margins, vascular invasion and high histological grade are all independent prognostic factors with a negative impact on survival in salivary gland carcinoma patients. This knowledge can be helpful in guiding clinicians in daily work and choice of treatment across the large variety of salivary gland carcinoma subtypes.


Acta Oncologica | 2015

Quality assurance of radiation therapy for head and neck cancer patients treated in DAHANCA 10 randomized trial.

Christian Hansen; Jørgen Johansen; Claus A. Kristensen; B. Smulders; Lisbeth Juhler Andersen; E. Samsøe; Elo Andersen; Jørgen B. B. Petersen; Jens Overgaard; Cai Grau

1Laboratory of Radiation Physics, Odense University Hospital, Denmark, 2Department of Oncology, Odense University Hospital, Denmark, 3Department of Oncology, Finsen Centre, Copenhagen University Hospital, Denmark, 4Department of Oncology, Aalborg Hospital, Denmark, 5Department of Oncology, Division of Radiophysics, University Hospital Herlev, Denmark, 6Department of Oncology, University Hospital Herlev, Denmark, 7Department of Medical Physics, Aarhus University Hospital, Denmark, 8Department of Experimental Clinical Oncology, Aarhus University Hospital, Denmark and 9Department of Oncology, Aarhus University Hospital, Denmark


Auris Nasus Larynx | 2012

Salivary gland carcinomas of the larynx: A national study in Denmark

Troels Krogh Nielsen; Kristine Bjørndal; Annelise Krogdahl; Hanne Primdahl; Claus A. Kristensen; Elo Andersen; Christian Godballe

OBJECTIVE Salivary gland carcinomas of the larynx are rare. The purpose of this study is to present a national series of laryngeal salivary gland carcinoma patients and to bring a review of recent literature. METHODS By merging The Danish Cancer Registry, The National Pathology Registry and The National Patient Registry all registered patients with laryngeal salivary carcinomas diagnosed from 1990 to 2007 were identified. The histological slides were reviewed and data concerning age, sex, symptoms, topography, histology, treatment and outcome were registered. Based on a supplemented PubMed search a review of literature from 1991 to 2010 was performed. RESULTS Six Danish patients with a malignant salivary gland tumor in the larynx were identified resulting in an incidence of 0.001/100,000 inhabitants/year. Four had adenoid cystic carcinoma and two a mucoepidermoid carcinoma. All patients were male. The patients were treated with surgery and/or radiotherapy. Three patients had recurrent disease. One died of the primary disease and one died of other causes. Four are alive with no evidence of disease. Merging of actual study group with patients from recent literature resulted in 83 cases. The male vs. female ratio was 2:1, the most common location was the supraglottic region (52%) and the most predominant histological subtypes were adenoid cystic carcinoma (46%), mucoepidermoid carcinoma (35%) and adenocarcinoma NOS (12%). CONCLUSION Laryngeal salivary gland carcinoma is a rare disease with a male predominance and most often localized in the supraglottic region. Data concerning treatment and outcome are scarce, but primary surgery with utmost focus on free surgical margins is the treatment of choice. Recurrences are observed later than ten years after primary treatment and a long follow up time is advocated.


Oral Oncology | 2016

Polymorphous low-grade adenocarcinoma: A Danish national study

Mohammad Talal Elhakim; Helle Breinholt; Christian Godballe; Lisbeth Juhler Andersen; Hanne Primdahl; Claus A. Kristensen; Kristine Bjørndal

OBJECTIVES To present a national series of polymorphous low-grade adenocarcinoma (PLGA) patients, including survival rates and an analysis of prognostic factors. MATERIALS AND METHODS By merging three Danish nationwide registries, 73 patients diagnosed with PLGA from 1990 to 2005 were identified. Histological slides were reviewed and data concerning demographics, tumour site, clinical stage, treatment profiles and follow-up were retrieved. Survival estimates and prognostic factors were evaluated by comparing Kaplan-Meier plots using the Mantel-Haenszel log-rank test. RESULTS Of the 73 patients, 47 (64%) were female. Median age was 58years. The most common location was the palate (73%). Median latency was five months. Recurrence was seen in 13% of patients. Overall survival (OS), disease-specific survival (DSS) and recurrence-free survival (RFS) rates after 10years were 73%, 99% and 83%, respectively. Univariate analyses suggested that free resection margins significantly improve RFS. CONCLUSION PLGA usually has an excellent survival outcome even in cases of advanced stage disease and locoregional recurrence. Primary choice of treatment should be complete surgical excision. Although there is no convincing evidence for the efficacy of adjuvant radiotherapy, it should still be considered, particularly in cases of involved resection margins and advanced stage disease. Late recurrences are common and respond well to salvage therapy.


Journal of Oral Pathology & Medicine | 2016

Salivary duct carcinoma: A Danish national study

Helle Breinholt; Mohammad Talal Elhakim; Christian Godballe; Lisbeth Juhler Andersen; Hanne Primdahl; Claus A. Kristensen; Kristine Bjørndal

BACKGROUND To present the first national series of salivary duct carcinoma patients, including survival rates and an analysis of prognostic factors. METHODS By merging three Danish nationwide registries that encompass an entire population, 34 patients diagnosed with salivary duct carcinoma from 1990 to 2005 were identified. Histological slides were reviewed, and data concerning demographics, tumour site, clinical stage, treatment profiles and follow-up were retrieved. Survival estimates and prognostic factors were evaluated by comparing Kaplan-Meier plots using the Mantel-Haenszel log-rank test. RESULTS Salivary duct carcinoma showed an incidence of 0.04/100.000 inhabitants/year. Distant recurrence was seen in 52% of patients. Five-year overall survival, disease-specific survival and recurrence-free survival were 32%, 42% and 35%, respectively. Univariate analyses suggested that overall stage (III/IV) and vascular invasion have a negative impact on all survival measures. Involved resection margins correlated with a poorer overall survival and disease-specific survival, whereas adjuvant radiotherapy improved overall survival and recurrence-free survival. CONCLUSIONS Salivary duct carcinoma incidence averages to two episodes per year in the entire Kingdom of Denmark. With half of patients in this study experiencing distant recurrences and only a third surviving at 5 years, prognosis is dismal. Advanced overall stage, vascular invasion and involved resection margins all seem to correlate with a poorer survival, while adjuvant radiotherapy significantly improved outcome. Extensive T-site surgery, neck dissection and adjuvant radiotherapy are therefore recommended.

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Jørgen Johansen

Aarhus University Hospital

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Annelise Krogdahl

Odense University Hospital

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Mie Topholm Bruun

Odense University Hospital

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Mikkel Christian Alanin

Copenhagen University Hospital

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