Is chemoradiation as effective as surgery with postoperative radiotherapy for locally advanced (operable) head and neck cancer? A retrospective observational study

OBJECTIVE: To determine whether chemoradiation (CX) is as effective as surgery with postoperative radiotherapy (SX) for operable, locally advanced head and neck cancer (LAHNC). METHODS: A retrospective review of 78 patients with operable stage III or IV cancer of the upper aerodigestive tract who were treated by CX (n = 25) or SX (n = 53) during a 20-year period was undertaken. RESULTS: Fewer patients relapsed regionally when treated by SX than by CX (p = 0.006). On the other hand, there was no significant difference in local recurrence, distant metastasis, 2-year survival rate, or 5-year survival rate between the two patient groups. CONCLUSION: Our results suggesting that CX is not as effective as SX for patients with operable LAHNC calls for a randomized trial comparing CX to SX in such cases.     

Is VMAT beneficial for patients undergoing radiotherapy to the head and neck?

Volumetric Intensity-Modulated Arc Therapy (VMAT) offers solutions to the time consuming, higher monitor unit (MU) delivery of Intensity-Modulated Radiotherapy (IMRT) for patients undergoing radiotherapy for head and neck cancer (HNC). Thus the aim was to determine whether VMAT would be beneficial for these patients.The majority of literature was planning comparative studies with only two studies on early clinical experience. Main themes arising from literature were conformity and homogeneity, organs at risk (OAR), MU and delivery time.VMAT provides plans with similar conformity, better homogeneity and results for improved sparing of OAR compared to IMRT. Thus it is clear that VMAT would be able to match the performance of IMRT plans, with the ability to treat patients in a short space of time and less MU. There is little clinical data on the side effects of VMAT, and more is needed to further evaluate the efficacy of VMAT. Overall these are encouraging results of VMAT for patients with HNC.     

What is the prognostic impact of FDG PET in locally advanced head and neck squamous cell carcinoma treated with concomitant chemo-radiotherapy? A systematic review and meta-analysis

Purpose

Evidence is conflicting on the prognostic value of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in head and neck squamous cell carcinoma. The aim of our study was to determine the impact of semiquantitative and qualitative metabolic parameters on the outcome in patients managed with standard treatment for locally advanced disease.

Methods

A systematic review of the literature was conducted. A meta-analysis was performed of studies providing estimates of relative risk (RR) for the association between semiquantitative metabolic parameters and efficacy outcome measures.

Results

The analysis included 25 studies, for a total of 2,223 subjects. The most frequent primary tumour site was the oropharynx (1,150/2,223 patients, 51.7%). According to the available data, the majority of patients had stage III/IV disease (1,709/1,799, 94.9%; no information available in four studies) and were treated with standard concurrent chemoradiotherapy (1,562/2,009 patients, 77.7%; only one study without available information). A total of 11, 8 and 4 independent studies provided RR estimates for the association between baseline FDG PET metrics and overall survival (OS), progression-free survival (PFS) and locoregional control (LRC), respectively. High pretreatment metabolic tumour volume (MTV) was significantly associated with a worse OS (summary RR 1.86, 95% CI 1.08–3.21), PFS (summary RR 1.81, 95% CI 1.14–2.89) and LRC (summary RR 3.49, 95% CI 1.65–7.35). Given the large heterogeneity (I² >?50%) affecting the summary measures, no cumulative threshold for an unfavourable prognosis could be defined. No statistically significant association was found between SUV_max and any of the outcome measures.

Conclusion

FDG PET has prognostic relevance in the context of locally advanced head and neck squamous cell carcinoma. Pretreatment MTV is the only metabolic variable with a significant impact on patient outcome. Because of the heterogeneity and the lack of standardized methodology, no definitive conclusions on optimal cut-off values can be drawn.

     

Unilateral cochlea sparing in locoregionally advanced head and neck cancer: a planning study

Background

Cochlea sparing can reduce late ototoxicity in head and neck cancer patients treated with cisplatin-based radiochemotherapy. In this situation, a mean cochlear dose (MCD) constraint of 10?Gy has been suggested by others based on the dose–effect relationship of clinical data. We aimed to investigate whether this is feasible for primary and postoperative radiochemotherapy in locoregionally advanced tumors without compromising target coverage.

Patients and methods

Ten patients treated with definitive and ten patients treated with adjuvant intensity-modulated radiotherapy (IMRT) and concurrent chemotherapy were investigated. The cochleae and a planning risk volume (PRV) with a 3?mm margin were newly delineated, whereas target volumes and other organs at risk were not changed. The initial plan was recalculated with a constraint of 10?Gy (MCD) on the low-risk side. The quality of the resulting plan was evaluated using the difference in the equivalent uniform dose (EUD).

Results

A unilateral MCD of below 10?Gy could be achieved in every patient. The mean MCD was 6.8?Gy in the adjuvant cohort and 7.6?Gy in the definitive cohort, while the non-spared side showed a mean MCD of 18.7 and 30.3?Gy, respectively. The mean PRV doses were 7.8 and 8.4?Gy for the spared side and 18.5 and 29.8?Gy for the non-spared side, respectively. The mean EUD values of the initial and recalculated plans were identical. Target volume was not compromised.

Conclusion

Unilateral cochlea sparing with an MCD of less than 10?Gy is feasible without compromising the target volume or dose coverage in locoregionally advanced head and neck cancer patients treated with IMRT. A prospective evaluation of the clinical benefit of this approach as well as further investigation of the dose–response relationship for future treatment modification appears promising.

     

Split-course accelerated hyperfractionated irradiation (CHA-CHA) as a sole treatment for advanced head and neck cancer patients—final results of a randomized clinical trial

Objective:

Evaluation of the efficacy and toxicity of split-course accelerated hyperfractionated irradiation (CHA-CHA) as a sole treatment for advanced head and neck (H&N) cancer patients.

Methods:

We enrolled 101 patients (39 in CHA-CHA and 37 in conventional (Conv.) arm completed the treatment). The CHA-CHA arm patients were irradiated twice a day, 7 days a week, using a fraction dose (fd) of 1.6 Gy up to 64 Gy with an 8-day gap in midterm. Patients in the control (Conv.) arm group were irradiated with a fd of 2 Gy, five times a week to a total dose of 72–74 Gy in the overall treatment time of 50–53 days. Quality of life (QOL) and acute mucosal reaction were evaluated during radiotherapy (RT). After RT, we followed the effect of treatment, QOL, performance status and adverse effects of radiation. For statistical analysis mainly a hierarchical multilevel modelling was used.

Results:

QOL was most deteriorated in the CHA-CHA arm; the CHA-CHA scheme also caused a relatively stronger acute injury. There were no significant differences in late adverse effects. In the CHA-CHA arm in 35% and in Conv. arm in 30% of patients, disease was controlled during follow-up. Tumour regression 1 year after the treatment was significantly better in the CHA-CHA arm. However, the overall survival rate analysis did not show significant difference between both arms.

Conclusion:

Despite differences in treatment results, we cannot conclude that split-course accelerated hyperfractionated irradiation is superior to conventionally fractionated RT as a sole treatment for advanced H&N cancer patients.

Advances in knowledge:

Obtained results in the context of published data support the statement that altered fractionations alone do not give an advantage for advanced H&N cancer patients.There are, and have been, many attempts to create a clear and effective treatment modality for advanced inoperable head and neck (H&N) cancers. The most common are different combinations of chemoradiotherapy, or different schedules of altered and usually intensive radiation treatment. It is clear that intense dose delivery combined with a high total dose (TD) and short treatment time gives a higher probability of tumour destruction; unfortunately, it is also connected with a higher, usually unacceptable, risk of normal tissue damage. One of the causes of radiation toxicity in such cases is the inability of sufficient repair of healthy tissue damage.The reason for this is the intensity of dose delivery and the lack of time for repopulation of normal cells and proper repair. On the other hand, the accelerated repopulation of squamous cancer cells starts 4 weeks after radiotherapy (RT); therefore, radiation treatment should be completed in that time. Considering the aforementioned facts, we tried to construct a very intense and short RT schedule allowing for normal tissue (mainly mucosa) repair. We went back to the old concept of split-course RT and combined it with accelerated, continuous, intense hyperfractionation.Finally, we proposed twice-a-day irradiation, using fraction doses of 1.6 Gy, 7 days a week up to a TD of 32 Gy, an 8-day gap and the repetition of such course. Using this schedule, the treatment was completed exactly within 4 weeks to avoid repopulation of accelerated tumour clonogens and the 8-day gap in the midterm allowed for normal tissue repair.     

Does weight loss predict accuracy of setup in head and neck cancer patients treated with Intensity-Modulated Radiation Therapy?

Purpose

This prospective study reports the impact of weight loss on setup of head and neck (H&;N) cancer patients treated by Intensity-Modulated Radiation Therapy (IMRT).

Materials and methods

Setup errors of H&;N cancer patients treated by IMRT from January to June 2010 were prospectively analysed and statistically related to weight loss. A mixed linear model was used for statistical evaluations. Setup margins of our institute were also calculated.

Results

Twenty-two patients and 128 pairs of Electronic Portal Images (EPI) were analysed. Setup errors varied between ?0.6 and +0.6, ?0.7 and +0.8 and ?0.2 and +0.8 in the anterior-posterior, superior-inferior and right-left direction, respectively. Median and mean weight loss were 2.1 and 3.1 kg (range 0?C12 kg), respectively; median and mean percent of weight loss were 2.95% and 4.64% (range 0.3?C19.7%), respectively. No statistical relation was seen between weight loss and the setup errors.

Conclusions

Weight loss is not a good clinical parameters for predicting an increase of setup errors. Other clinical and/or anthropometrical features should be prospectively evaluated in order to assess the need for re-planning.     

Value of fluorodeoxyglucose positron emission tomography before radiotherapy for head and neck cancer: does the standardized uptake value predict treatment outcome?

Purpose  The aim of this study was to determine if the standardized uptake value (SUV) of fluorodeoxyglucose positron emission tomography (FDG-PET) for head and neck cancer can predict the outcome of radiotherapy and if the SUV is correlated with histological grade, mitosis, and apoptosis. Materials and methods  The study included 45 head and neck cancer patients who underwent FDG-PET scanning before radiotherapy. The maximum SUV (SUVmax) of their primary lesions were measured. Biopsy was performed in all patients to determine the histological diagnosis. Altogether, 14 biopsy specimens were available for mitotic and apoptotic cell counts. Results  The mean SUVmax of T3 tumors was significantly higher than that of T1 (P = 0.01) and T2 (P = 0.011) tumors. The mean SUVmax of stage II disease was signifirfcantly lower than that of stage III (P = 0.028) and stage IV (P = 0.007) disease. There was a tendency toward a better locoregional control rate and disease-free survival for the lower SUV group using a cutoff value of 5.5. For 41 patients with squamous cell carcinoma or undifferentiated carcinoma, SUVmax did not reflect the histological grade. There was no correlation between the SUVmax and the mitotic/apoptotic status. Conclusion  SUVmax may correlate with the T classification and stage, but there was no predictive value for outcome of radiation therapy. Neither histological grading nor mitotic/apoptotic status is correlated with SUVmax.     

High expression of nuclear survivin and Aurora?B predicts poor overall survival in patients with head and neck squamous cell cancer

Background and purpose

Survivin is one of the apoptosis inhibitor proteins. Together with Aurora?B, it also plays a role in regulating several aspects of mitosis. High expression of these markers is correlated with malignant behavior of various cancers and resistance to therapy. Our aim was to evaluate the prognostic role of these markers in head and neck cancers.

Patients and methods

We evaluated the expression of Aurora B and survivin in tissue specimens of 58 patients with head and neck squamous cell carcinoma using immunohistochemistry.

Results

Patients who showed high expression of cytoplasmic and nuclear survivin and Aurora B had significantly shorter overall survival (p?=?0.036, p?Conclusion The negative prognostic values of high expression of Aurora B and high co-expression of nuclear survivin and Aurora B on survival were shown. These findings suggest that co-expression of nuclear survivin and Aurora B can be useful diagnostic markers and therapeutic targets for head and neck squamous cell carcinoma. However, further studies with a larger number of patients in a more homogeneous disease group are needed to confirm the conclusion.     

FDG positron emission tomography in head and neck cancer: pitfall or pathology?

PURPOSE: Fluorodeoxyglucose (FDG) positron emission tomography (PET) is a functional imaging technique used for imaging and staging malignant diseases. In many oncologic situations, however, abnormal changes seen on the PET studies are not caused by tumor, which is especially true in the head and neck region. The authors present an overview of the phenomena that may confound the interpretation of the images in head and neck cancer. MATERIALS AND METHODS: FDG PET studies were performed in patients with primary head and neck cancer and in patients in whom recurrent disease was likely. The results were correlated with clinical findings. Eight solitary cases were selected from a total of 180 patients studied. RESULTS AND CONCLUSIONS: Benign lesions and iatrogenic and physiologic changes may show increased FDG uptake. Therefore, clinical information on previous surgical interventions and optimal patient preparation are necessary for adequate interpretation. If these prerequisites can be met, benign lesions appear to be the only lesions that may interfere with the specificity of FDG PET.     

Do hardware artefacts influence the performance of head and neck PET scans in patients with oral cavity squamous cell cancer?

OBJECTIVE: The purpose of this study was to evaluate the influence of (68)Ge-based and CT-based attenuation correction as well as two standard image reconstruction algorithms on the appearance of artefacts due to dental hardware. Additionally, the intensity of such artefacts was compared with (18)F-fluorodeoxyglucose (FDG) uptake in patients with known oral cavity squamous cell cancer. METHODS: Thirty-two metallic and non-metallic objects used for dentistry/dental surgery were scanned in a water-bath filled with FDG on a combined PET/CT scanner. Images were reconstructed with either CT-based or (68)Ge-based transmission data and by using iterative reconstruction or filtered backprojection. The intensity of artefacts was assessed visually using a subjective scale from 0 (no artefact visible) to 4 (very strong artefact), and by quantitative measurements. In a second study, images of 30 patients with known squamous cell cancer and dental hardware were retrospectively analysed by two observers, again using a visual assessment grading system. Wilcoxon signed rank test was used for statistical comparisons. RESULTS: Eighteen of 32 objects caused artefacts, which were visible with both attenuation correction methods. CT-based attenuation correction was visually more intense than (68)Ge-based attenuation correction (P<0.0001), and the measured (18)F concentration was also higher (P=0.0002). No difference was found between the reconstruction algorithms. In 28 of 30 patients the primary tumour was visible. FDG uptake in the primary tumour was significantly higher than measured (18)F concentration in artefacts (P<0.0001). CONCLUSION: Attenuation correction of PET images generates artefacts adjacent to dental hardware that mimic FDG uptake. In this series, the primary lesion was discriminated from artefacts.     

Interstitial pulsed-dose-rate brachytherapy for head and neck cancer—Single-institution long-term results of 385 patients

PurposeTo assess the long-term results of protocol-based pulsed-dose-rate (PDR) interstitial brachytherapy (iBT) in 385 patients with head and neck cancer who underwent PDR-iBT preferably after minimal, nonmutilating surgery.Methods and MaterialsFrom 1997 to 2009, a total of 385 patients received protocol-based PDR-iBT for head and neck cancer. Brachytherapy was preceded by surgery in most of our patients (326/385, 84.7%). Altogether, 246 of 385 patients (63.9%) received iBT alone and 135 of 385 patients (36.1%) in combination with external beam radiation therapy. The analysis was done after a median followup of 63 months.ResultsThe 5-, 10-, and 15-year local relapse-free survival rates according to Kaplan–Meier test for all analyzed patients were 85.8%, 83.1%, and 80.2%, respectively. The 5-, 10-, and 15-year overall survival and disease-free survival rates were 68.9%, 52.2%, and 44.1%, and 81.3%, 79.3%, and 76.3%, respectively. For N0-/N1- vs. N2-patients, we observed significantly different 5-year local recurrence-free survival rates with values of 92.3% and 73.7%, respectively (p = 0.007). No other patient or treatment-related parameters had a significant influence on treatment results. Serious late side effects, such as soft tissue or bone necrosis, were observed in 39 of 385 patients (10.2%) and 18 of 385 patients (4.9%), respectively.ConclusionsThe PDR-iBT with 0.4–0.7 Gy each hour, 24 h per day for patients with head and neck cancer is a proven, effective, and safe treatment method with excellent long-term data.     

Once-daily radiotherapy to ≥59.4 Gy versus twice-daily radiotherapy to ≥45.0 Gy with concurrent chemotherapy for limited-stage small-cell lung cancer: a comparative analysis of toxicities and outcomes

Purpose  

The aim of this study was to compare toxicities, disease control, survival outcomes, and patterns of failure between groups of limited-stage small-cell lung cancer patients treated with once-daily versus twice-daily radiotherapy and concurrent chemotherapy.     

Fibroblast growth factor 2 is of prognostic value for patients with locally advanced squamous cell carcinoma of the head and neck

Background and purpose

Patients with locally advanced SCCHN have a poor prognosis. This study investigated the prognostic value of the tumor cell expression of the fibroblast growth factor 2 (FGF-2) in patients treated with surgery followed by radiotherapy.

Patients and methods

The impact of FGF-2-expression and 11 additional potential prognostic factors on loco-regional control (LRC), metastases-free survival (MFS), and overall survival (OS) was retrospectively evaluated in 146 patients. Additional factors included age, gender, performance status, pre-radiotherapy hemoglobin levels, tumor site, histologic grade, T-category, N-category, human papilloma virus (HPV) status, extent of resection, and chemotherapy. Univariate analyses were performed with the Kaplan-Meier method and the log-rank test, multivariate analyses with the Cox proportional hazard model.

Results

On multivariate analysis, improved LRC was significantly associated with FGF-2-negativity [risk ratio (RR): 7.33; 95?%-confidence interval (CI): 2.88–19.05; p?<?0.001], lower T-category (RR: 2.42; 95?%-CI: 1.47–4.33; p?<?0.001), lower N-category (RR: 12.36; 95?%-CI: 3.48–78.91; p?<?0.001), and pre-radiotherapy hemoglobin levels ≥?12 g/dl (RR: 4.18; 95?%-CI: 1.73–10.53; p?=?0.002). No factor was significantly associated with improved MFS. Lower T-category showed a trend (RR: 1.59; 95?%-CI: 0.97–2.82; p?=?0.069). Better OS was significantly associated with FGF-2-negativity (RR: 5.10; 2.22–11.80; p?<?0.001), lower T-category (RR: 2.17; 95?%-CI: 1.38–3.68; p?<?0.001), lower N-category (RR: 3.86; 95?%-CI: 1.60–10.85; p?=?0.002), and pre-radiotherapy hemoglobin levels ≥?12 g/dl (RR: 3.20; 95?%-CI: 1.46–7.30; p?=?0.004). HPV-positivity showed a trend (RR: 2.36; 95?%-CI: n.a.; p?=?0.054).

Conclusions

Tumor cell expression of FGF-2 proved to be an independent prognostic factor for LRC and OS. This factor can help personalize treatment and stratify patients in future trials.     

Can FDG PET predict radiation treatment outcome in head and neck cancer? Results of a prospective study

Purpose  

In head and neck cancer (HNC) various treatment strategies have been developed to improve outcome, but selecting patients for these intensified treatments remains difficult. Therefore, identification of novel pretreatment assays to predict outcome is of interest. In HNC there are indications that pretreatment tumour ¹⁸F-fluorodeoxyglucose (FDG) uptake may be an independent prognostic factor. The aim of this study was to assess the prognostic value of FDG uptake and CT-based and FDG PET-based primary tumour volume measurements in patients with HNC treated with (chemo)radiotherapy.     

Dose–volume-related dysphagia after constrictor muscles definition in head and neck cancer intensity-modulated radiation treatment

Objective:

Dysphagia remains a side effect influencing the quality of life of patients with head and neck cancer (HNC) after radiotherapy. We evaluated the relationship between planned dose involvement and acute and late dysphagia in patients with HNC treated with intensity-modulated radiation therapy (IMRT), after a recontouring of constrictor muscles (PCs) and the cricopharyngeal muscle (CM).

Methods:

Between December 2011 and December 2013, 56 patients with histologically proven HNC were treated with IMRT or volumetric-modulated arc therapy. The PCs and CM were recontoured. Correlations between acute and late toxicity and dosimetric parameters were evaluated. End points were analysed using univariate logistic regression.

Results:

An increasing risk to develop acute dysphagia was observed when constraints to the middle PCs were not respected [mean dose (D_mean) ≥50 Gy, maximum dose (D_max) >60 Gy, V50 >70% with a p = 0.05]. The superior PC was not correlated with acute toxicity but only with late dysphagia. The inferior PC was not correlated with dysphagia; for the CM only, D_max >60 Gy was correlated with acute dysphagia ≥ grade 2.

Conclusion:

According to our analysis, the superior PC has a major role, being correlated with dysphagia at 3 and 6 months after treatments; the middle PC maintains this correlation only at 3 months from the beginning of radiotherapy, but it does not have influence on late dysphagia. The inferior PC and CM have a minimum impact on swallowing symptoms.

Advances in knowledge:

We used recent guidelines to define dose constraints of the PCs and CM. Two results emerge in the present analysis: the superior PC influences late dysphagia, while the middle PC influences acute dysphagia.In the past decade, substantial progress has been made in the treatment of head and neck cancer (HNC). Several reports show that radiotherapy (RT) with concomitant chemotherapy or altered fractionation schedules improve tumour control and survival rate.^1,2However, xerostomia and dysphagia often remain relevant side effects for patients with HNC, compromising their quality of life (QoL), as a consequence of radiation damage to the parotid glands and to the organ at risk (OAR) involved in the swallowing process (SWOARs).³Intensity-modulated radiation therapy (IMRT) and rotational intensity-modulated techniques, including volumetric-modulated arc therapy (VMAT), allow for a better dose conformation to target structures while reducing the dose.^4–8 In comparison with three-dimensional-conformal radiation therapy, several studies have shown that IMRT in HNC treatment reduces overall adverse effects such as xerostomia and dysphagia and thus improves QoL, even when chemotherapy is added.^9–13Regarding tolerance of the parotid glands, several studies have suggested significant recovery when the mean dose is inferior to 26 Gy. Open questions remain for SWOARs, especially with reference to the delineation modalities of the involved structures to the volumes or the dose constraints to be applied.^14–18 More authors hypothesized that sparing a portion of the constrictor muscles (PCs), not involved by tumour and not at risk of subclinical disease, might reduce dysphagia.^19–21 These studies obtained different results, maybe, owing to a number of methodological issues and to the ambiguous contouring of the PCs. For this purpose, Christianen et al²² recently defined guidelines for SWOARs contouring.Based on these findings, the aim of this retrospective analysis is to evaluate potential relationships between planned dose–volume parameters and observed incidence of acute and late dysphagia in patients with HNC treated with IMRT or VMAT, after a recontouring of the PCs according to these recently published guidelines.     

Does primary tumour volumetry performed early in the course of definitive concomitant chemoradiotherapy for head and neck squamous cell carcinoma improve prediction of primary site outcome?

Although previous studies have documented correlations between pre-treatment or post-treatment primary tumour volumes and local outcome following definitive concomitant chemoradiotherapy (CCRT) in head and neck squamous cell carcinoma (HNSCC), no study has included and compared tumour volumes during CCRT. We reviewed the MRIs of 69 HNSCC patients treated with a 6 weeks course of CCRT and who underwent successful MRI pre-treatment (n = 69), 2 weeks intra-treatment (n = 48) and 6 weeks post-treatment (n = 61). Primary tumour volumes on MRI at the three time points were calculated and compared for their predictive value for primary site outcome. Volume thresholds optimised to predict failure with the highest accuracy and positive predictive value (PPV) were calculated. The mean pre-treatment volume was 24.6 cm3 (range, 1.1-187.9 cm3) and the mean follow-up interval was 41 months (range, 12-100 months). 23 primary tumours failed treatment (33%). Volumes before, during and after CCRT were positively associated with local failure (p = 0.015, p = 0.009, p<0.0001). Volume reductions during and after CCRT were negatively associated with local failure (p = 0.021, p = 0.001). Pre-treatment and intra-treatment volume thresholds achieved the highest accuracy and produced intermediate PPVs (51-64%) for predicting local failure. Optimised intra-treatment thresholds did not identify any more treatment failures than the pre-treatment thresholds. By comparison, a 6 weeks post-treatment volume reduction (<35%) achieved 100% PPV for failure, albeit with 26% sensitivity. In conclusion, primary tumour volumetry performed early in CCRT provides minimal additional information compared with pre-treatment volumetry, with respect to predicting post-treatment local failures. Therefore, volumetry during CCRT is unlikely to be useful for guiding individual response-based therapeutic modifications.     

Embolization with “Ethibloc” of vascular tumors and arteriovenous malformations in the head and neck

Summary Ethibloc has been used almost exclusively until now for embolization of tumors and bleeding vessels in the liver and kidney. Unlike with Gelfoam-particles, there is no recanalization. The resorption occurs so slowly that there is no interference with the necrosis of the embolized tumor. Due to its low viscosity, it passes catheters with thin lumina and fills the capillary bed of the tumor without danger of reaching the venous vessels. In this paper we describe a new technic of percutaneous catheter-embolization with Ethibloc using a coaxial catheter which we believe enhances safety and effectiveness. It has been successfully used in five patients. In the meantime two more patients have been treated successfully.Presented in part at the 17th Annual Meeting of the German Society of Neuroradiology, 9–10 October 1981 in Tübingen, FRG.