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Biomedical subjects

Michael Flentje

Publications and source records attributed to Michael Flentje.

At least 37 records · Page 2Linked to original sources
PubMed2006

Three-dimensional spatial modelling of the correlation between abdominal motion and lung tumour motion with breathing.

The aim of this research was to investigate whether a spatial correlation could be found between an external 3-D respiratory signal and the tumour trajectory. The respiratory signal was obtained by tracking the abdominal movement and the tumour trajectory was obtained by automatically determining the tumour position in a series of portal images. Three different models, based on Systems Identification, are presented to model the correlation using a 1-D respiratory signal, a 3-D respiratory signal and a 3-D respiratory signal together with previously determined tumour positions. Adequate correlation was found for all models in the direction of the tumour movement with standard deviations of 0.89 mm, 0.72 mm and 0.75 mm, respectively, and model fit of Rt2 = 0.19, 0.63 and 0.82, respectively. Increasing the frame rate for the acquisition of portal images from 3 to 15 frames per second improved the standard deviation and model fit. In summary, it is possible to spatially correlate a 3-D respiratory signal with the tumour trajectory using this approach. The models presented provide a framework that can be extended to include more information if required. A 3-D respiratory signal is preferable to a 1-D signal in modelling the tumour motion that is not along the main axis of tumour movement.

Abdomen↗
PubMed2006

Stereotactic radiotherapy of primary liver cancer and hepatic metastases.

The purpose was to evaluate the clinical results of stereotactic radiotherapy in primary liver tumors and hepatic metastases. Five patients with primary liver cancer and 39 patients with 51 hepatic metastases were treated by stereotactic radiotherapy since 1997. Twenty-eight targets were treated in a "low-dose"-group with 3 x 10 Gy (n = 27) or 4 x 7 Gy (n = 1) prescribed to the PTV-encl. 65%-isodose. In a "high-dose"-group patients were treated with 3 x 12 - 12.5 Gy (n = 19; same dose prescription) or 1 x 26 Gy/PTV-enclosing 80%-isodose (n = 9). Median follow-up was 15 months (2-48 months) for primary liver cancer and 15 months (2-85 months) for hepatic metastases. While all primary liver cancers were controlled, nine local failures (3-19 months) of 51 metastases were observed resulting in an actuarial local control rate of 92% after 12 months and 66% after 24 months and later. A borderline significant correlation between dose and local control was observed (p = 0.077): the actuarial local control rate after 12 and 24 months was 86% and 58% in the low-dose-group versus 100% and 82% in the high-dose-group. In multivariate analysis high versus low-dose was the only significant factor predicting local control (p = 0.0089). Overall survival after 1 and 2 years was 72% and 32% for all patients and was impaired due to systemic progression of disease. No severe acute or late toxicity exceeding RTOG/EORTC-score 2 were observed. Stereotactic irradiation of primary liver cancer and hepatic metastases offers a locally effective treatment without significant complications in patients, who are not amenable for surgery. Patient selection is important, because those with low risk for systemic progression are more likely to benefit from this approach.

Adolescent↗
PubMed2006

Cone-beam CT based image-guidance for extracranial stereotactic radiotherapy of intrapulmonary tumors.

Cone-beam CT (CB-CT) based image-guidance was evaluated for extracranial stereotactic radiotherapy of intrapulmonary tumors. A total of 21 patients (25 lesions: prim. NSCLC n = 6; pulmonary metastases n = 19) were treated with stereotactic radiotherapy (1 to 8 fractions). Prior to every fraction a CB-CT was acquired in treatment position, errors between planned and actual tumor position were measured and corrected. Intra- and inter-observer variability of manual evaluation of tumor position error was investigated and this manual method was compared with automatic image registration. Based on CB-CTs from 66 fractions the discrepancy (3-D vector) between planned and actual tumor position was 7.7 mm +/-1.3 mm. Tumor position error relative to the bony anatomy was 5.3 mm +/-1.2 mm, the correlation between bony anatomy and tumor position was poor. Intra-observer and inter-observer variability of manual evaluation of tumor position error was 0.9 mm +/-0.8 mm and 2.3 mm +/-1.1 mm, respectively. Automatic image registration showed highly reproducible results (<1 mm). However, compared with manual registration a systematic error was found in direction of predominant tumor breathing motion (2.5 mm vs 1.4 mm). Image-guidance using CB-CT was validated for high precision radiotherapy of intrapulmonary tumors. It was shown that both the planning reference and the verification image study have to consider tumor breathing motion.

Aged↗
PubMed2006

Tracking moving objects with megavoltage portal imaging: a feasibility study.

Four different algorithms were investigated with the aim to determine their suitability to track an object in conventional megavoltage portal images. The algorithms considered were the mean of the sum of squared differences (MSSD), mutual information (MI), the correlation ratio (CR), and the correlation coefficient (CC). Simulation studies were carried out with various image series containing a rigid object of interest that was moved along a predefined trajectory. For each of the series the signal-to-noise ratio (SNR) was varied to compare the performance of the algorithms under noisy conditions. For a poor SNR of -6 dB the mean tracking error was 2.4, 6.5, 39.0, and 17.2 pixels for MSSD, CC, CR and MI, respectively, with a standard deviation of 1.9, 12.9, 19.5, and 7.5 pixels, respectively. The size of a pixel was 0.5 mm. These results improved to 1.1, 1.3, 1.3, and 2.0 pixels, respectively, with a standard deviation of 0.6, 0.8, 0.8, and 2.1 pixels, respectively, when a mean filter was applied to the images prior to tracking. The implementation of MSSD into existing in-house software demonstrated that, depending on the search range, it was possible to process between 2 and 15 images/s, making this approach capable of real-time applications. In conclusion, the best geometric tracking accuracy overall was obtained with MSSD, followed by CC, CR, and MI. The simplest and best algorithm, both in terms of geometric accuracy as well as computational cost, was the MSSD algorithm and was therefore the method of choice.

Algorithms↗
PubMed2005

Glucose requirement for hypoxic accumulation of hypoxia-inducible factor-1alpha (HIF-1alpha).

Hypoxia-inducible factor-1alpha (HIF-1alpha) is both a potential endogenous marker of tumor hypoxia and therapeutic target, and elevated HIF-1alpha protein levels have been shown to be associated with increased hypoxic radiation resistance in FaDu human pharyngeal carcinoma cells in vitro. Here, we found that in FaDu xenografts, no significant HIF-1alpha protein accumulation was detectable by either flow cytometry or Western blot, despite the presence of hypoxic (pimonidazole-positive, radiation resistant) cells. To investigate the effect of different tumor microenvironment conditions on hypoxic HIF-1alpha accumulation, we performed in vitro hypoxia experiments (0.1% O2, 24 h) with manipulation of pH (7.4 vs. 6.7), glucose (0-5.5 mM) and serum (0 or 10%) availability in FaDu and HT 1080 human fibrosarcoma cells. Hypoxic induction of HIF-1alpha protein was strongly dependent on glucose availability and largely abolished at 0.55 mM glucose or less in both cell lines. This glucose effect was confirmed in a hypoxia-responsive-element (HRE)/enhanced-green-fluorescent-protein (EGFP) reporter assay in transfected HT 1080 cells and possibly explains a lack of HIF-1alpha protein in hypoxic tumor cells.

Animals↗
PubMed2005

Late small bowel toxicity after adjuvant treatment for rectal cancer.

BACKGROUND: For locally advanced rectal cancer surgery as sole treatment results in poor local control and survival. After adjuvant radiotherapy for locally advanced rectal cancer, small bowel toxicity has been the most frequent and serious side effect. The gain in survival and local control was accompanied by severe late chronic toxicity reducing the benefit of adjuvant treatment. REVIEW: Clinical factors, pathology and treatment of late small bowel toxicity after adjuvant radiotherapy for locally advanced rectal cancer will be discussed. This review will focus on different surgical and radiotherapeutic means reducing the risk of late small bowel damage.

Chemotherapy, Adjuvant↗
PubMed2005

Hypofractionated stereotactic re-irradiation: treatment option in recurrent malignant glioma.

BACKGROUND: Hypofractionated stereotactic radiotherapy (HFSRT) is one salvage treatment option in previously irradiated patients with recurrent malignant glioma. We analyzed the results of HFSRT and prognostic factors in a single-institution series. METHODS: Between 1997 and 2003, 19 patients with recurrent malignant glioma (14 glioblastoma on most recent histology, 5 anaplastic astrocytoma) were treated with HFSRT. The median interval from post-operative radiotherapy to HFSRT was 19 (range 3-116) months, the median daily single dose 5 (4-10) Gy, the median total dose 30 (20-30) Gy and the median planning target volume 15 (4-70) ml. RESULTS: The median overall survival (OS) was 9.3 (1.9-77.6+) months from the time of HFSRT, 15.4 months for grade III and 7.9 months for grade IV tumors (p = 0.029, log-rank test). Two patients were alive at 34.6 and 77.6 months. OS was longer after a total dose of 30 Gy (11.1 months) than after total doses of <30 Gy (7.4 months; p = 0.051). Of five (26%) reoperations, none was performed for presumed or histologically predominant radiation necrosis. Median time to tumor progression after HFSRT on imaging was 4.9 months (1.3 to 37.3) months. CONCLUSION: HFSRT with conservative total doses of no more than 30 Gy is safe and leads to similar OS times as more aggressive treatment schemes. In individual patients, HFSRT in combination with other salvage treatment modalities, was associated with long-term survival.

Antineoplastic Agents↗
PubMed2005

Characterization of carbonic anhydrase IX (CA IX) as an endogenous marker of chronic hypoxia in live human tumor cells.

PURPOSE: Published clinical studies provide conflicting data regarding the prognostic significance of carbonic anhydrase IX (CA IX) overexpression as an endogenous marker of tumor hypoxia and its comparability with other methods of hypoxia detection. We performed a systematic analysis of CA IX protein levels under various in vitro conditions of tumor hypoxia in HT 1080 human fibrosarcoma and FaDu human pharyngeal carcinoma cells. Because sorting of live CA IX positive cells from tumors provides a tool to study the radiosensitivity of chronically hypoxic cells, we modified and tested a CA IX flow cytometry protocol on mixed hypoxic/aerobic suspensions of HT 1080 and FaDu cells. METHODS AND MATERIALS: HT 1080 and FaDu cells were treated with up to 24 h of in vitro hypoxia and up to 96 h of reoxygenation. To test the effect of nonhypoxic stimuli, glucose and serum availability, pH and cell density were modified. CA IX protein was quantified in Western blots of whole-cell lysates. Mixed suspensions with known percentages of hypoxic cells were prepared for CA IX flow cytometry. The same mixtures were assayed for clonogenic survival after 10 Gy. RESULTS: Hypoxia-induced CA IX protein expression was seen after >6 h at < or =5% O(2), and protein was stable over 96 h of reoxygenation in both cell lines. Glucose deprivation abolished the hypoxic CA IX response, and high cell density caused CA IX induction under aerobic conditions. Measured percentages of CA IX-positive cells in mixtures closely reflected known percentages of hypoxic cells in HT 1080 and were associated with radioresistance of mixtures after 10 Gy. CONCLUSION: CA IX is a stable marker of current or previous chronic hypoxia but influenced by nonhypoxic stimuli. Except the time course of accumulation, all properties of this marker resembled our previous findings for hypoxia-inducible factor-1alpha. A modified flow cytometry protocol provided good separability of CA IX-negative and -positive cells in vitro and can be applied to sort chronically hypoxic cells from tumors.

Antigens, Neoplasm↗
PubMed2005

Influence of calculation model on dose distribution in stereotactic radiotherapy for pulmonary targets.

PURPOSE: To compare the pencil beam (PB) and collapsed cone (CC)-based three-dimensional dose calculation used for stereotactic irradiation of pulmonary targets. METHODS AND MATERIALS: Three-dimensional conformal dose distributions (using 6-MV and 18-MV photon beams) were generated for 33 pulmonary targets using the PB algorithm implemented in the Helax-TMS treatment planning system and then recalculated with the CC algorithm of TMS using an identical beam setup and parameters. The differences were analyzed by evaluating the dose-volume histograms for the planning target volume (PTV) and clinical target volume (CTV) and evaluating the computed absolute monitor units (MUs). The influence of the photon energy was also studied. For three cases, the results were compared with Monte-Carlo calculations. RESULTS: Use of the CC model typically showed increased dose inhomogeneity. Owing to a more accurate modeling of secondary charged particle disequilibrium at the tumor-lung interface, the beam penumbra is broadened. The median and mean target dose decreased by 13.9% and 11.2% for the PTV and 9.2% and 9.4% for the CTV, respectively, using the CC algorithm. Consequently, the average PTV dose coverage decreased by 7.1% (SD, 6.5%). On average, the MUs calculated to achieve the prescribed dose were 5.4% (SD, 5.8%) greater for the CC algorithm. The difference in MUs between the PB and CC increased with decreasing PTV size and high photon energy (18 MV; r = -0.68), reaching 26% at the maximum. CONCLUSION: The absorbed dose at the lung-tumor interface calculated by the PB algorithm was considerably greater than the dose calculated using the CC algorithm. In small targets (PTV < or = 100 cm(3)) and for 18-MV photons, the MUs calculated with PB may lead to an insufficient dose to the target volume.

Algorithms↗
PubMed2005

Radiotherapy of prostate cancer with multileaf collimators (MLCs) optimization of the undulating dose distribution at the MLC edge.

BACKGROUND AND PURPOSE: A technical modification for radiotherapy of prostate cancer is presented to smooth the scalloped dose pattern that occurs at treatment field edge, when a multileaf collimator (MLC) has been used. MATERIAL AND METHODS: Ten patients with prostate cancer receiving postoperative, adjuvant irradiation were studied prospectively. By a three-dimensional planning system (TMS, Helax 6.1B) the irradiation was planned for an 18-MV linear accelerator (Primus 1, Siemens). The volumes of interest (VOI) were the planning target volume (PTV; the region of the prostate including the seminal vesicles), the volume of rectum (V(rectum)) and urinary bladder (V(bladder)). Two four-field techniques (0 degrees , 90 degrees , 180 degrees , 270 degrees ) were planned using "beam's eye view" for setting the leaf position of the MLC. For technique A the MLC was adapted to the PTV using a 0 degrees collimator angle for the lateral fields. For technique B the collimator angle of the lateral fields was optimized to compensate the cascade field shape. Dose-volume histograms of PTV, V(rectum) and V(bladder) were analyzed. The dose was prescribed for the reference point according to ICRU 50. Film dosimetry was used to show the dose pattern at the field edge produced by the two techniques. RESULTS: Dose to PTV did not differ between technique A and B. Median dose to V(rectum) was 82.6% for technique A and 77.3% for technique B (p < 0.001). Technique A irradiates a larger V(rectum) than technique B being significant for all isodose levels tested. Median dose to V(bladder) did not differ for technique A and B (p > 0.05). CONCLUSION: The presented technical modification is an effective method to blur the staggered dose distribution that results, when the MLC is conventionally stepped to adapt to the dorsal, irregular PTV border in irradiation of prostate. Especially for irradiation to escalated dose levels, this modification may reduce the dose to the rectum and thus the rectal side effects in comparison to the conventional MLC fields.

Algorithms↗
PubMed2005

The influence of heterotopic ossification on functional status of hip joint following total hip arthroplasty.

PURPOSE: The functional failure induced by heterotopic ossification (HO) following total hip arthroplasty (THA) was analyzed and correlated to the radiologic failure. PATIENTS AND METHODS: From July 1997 to July 2001, 315 patients (345 hips) received THA indicated by a hypertrophic osteoarthritis of higher degree (Kellgren grade III, IV). All patients were irradiated prophylactically for prevention of HO on the evening before surgery with a 7-Gy single fraction. The patients' median age was 66.3 years. Radiologic failure was assessed by comparison of pre- and postoperative hip X-rays (immediately and 6 months after surgery). Analysis of radiographs was performed according to the Brooker Score. Clinical failure was appraised by measurement of passive range of motion (ROM) of the hip joint with a standard goniometer. The t-test was used for statistical analysis. RESULTS: 281 patients (81.5%) did not develop HO. HO of Brooker grade I or II was found in 58 patients (16.8%). Six patients (1.7%) developed HO Brooker grade III or IV. There was a significant negative correlation between the degree of radiologic and clinical failure. ROM differed significantly between patients with HO Brooker grade 0, I, II and patients with HO Brooker grade III, IV. Comparing the pre- and postoperative ROM, all patients with Brooker grade 0, I and II showed a significant improvement of flexion, internal and external rotation, abduction and adduction movement. Patients with HO Brooker grade III and IV showed no improvement of ROM in the postoperative follow-up. CONCLUSION: The development of HO following THA influences the physical function of the hip joint dependent on the degree of ossification. HO of lower degree (Brooker I, II) does not influence the clinical outcome, whereas HO of higher degree (Brooker III, IV) reduces the function of hip arthroplasty. Therefore, the purpose of a prophylactic therapy must be to reduce HO of higher degree.

Aged↗
PubMed2005

Response of the plasma hypoxia marker osteopontin to in vitro hypoxia in human tumor cells.

BACKGROUND: Osteopontin (OPN) is recognized as a tumor-associated protein and has recently been shown to be a potential plasma marker of tumor hypoxia in head and neck cancer patients. We sought to detect patterns of OPN accumulation and secretion in human tumor cells during in vitro hypoxia. MATERIALS AND METHODS: The human tumor cell lines A 549 lung carcinoma, U 87 malignant glioma, HT 1080 fibrosarcoma, FaDu pharyngeal carcinoma and HT 29 and HCT 116 colorectal carcinoma were treated with 1, 6 or 24 h of hypoxia (0.1% O2) or 24 h followed by 4 h or 20 of reoxygenation. OPN concentration in the supernatant was measured by ELISA, OPN protein and mRNA levels by Western and Northern blotting. RESULTS: In FaDu, HT 29 and HCT 116, OPN levels in the supernatant remained below 10 ng/ml under all conditions. In A 549, HT 1080 and U 87, mean aerobic OPN concentrations were 2296, 164 and 115 ng/ml, respectively. No increase of OPN in the medium during 24h of hypoxia, but moderate increases during subsequent 24-hour-reoxygenation were observed in these three cell lines. Intracellular OPN protein was present to a similar extent in all six-cell lines under aerobic conditions and also did not accumulate during hypoxia treatment. OPN mRNA response to hypoxia and reoxygenation was very heterogeneous between cell lines. CONCLUSION: Reoxygenation rather than hypoxia appears to induce OPN secretion from human tumor cells in a cell-type specific manner.

Cell Adhesion↗
PubMed2004

Stereotactic radiotherapy for primary lung cancer and pulmonary metastases: a noninvasive treatment approach in medically inoperable patients.

PURPOSE: The clinical results of dose escalation using stereotactic radiotherapy to increase local tumor control in medically inoperable patients with Stage I-II non-small-cell lung cancer or pulmonary metastases were evaluated. METHODS AND MATERIALS: Twenty patients with Stage I-II non-small-cell lung cancer and 41 patients with 51 pulmonary metastases not amenable to surgery were treated with stereotactic radiotherapy at 3 x 10 Gy (n = 19), 3 x 12-12.5 Gy to the planning target volume enclosing 100%-isodose, with normalization to 150% at the isocenter; n = 26) or 1 x 26 Gy to the planning target volume enclosing 80%-isodose (n = 26). The median follow-up was 11 months (range, 2-61 months) for primary lung cancer patients and 9 months (range, 2-37 months) for patients with metastases. RESULTS: The actuarial local control rate was 92% for lung cancer patients and 80% for metastasis patients > or =1 year after treatment and was significantly improved by increasing the dose from 3 x 10 Gy to 3 x 12-12.5 Gy or 1 x 26 Gy (p = 0.038). The overall survival rate after 1 and 2 years was 52% and 32%, respectively, for lung cancer patients and 85% and 33%, respectively, for metastasis patients, impaired because of systemic disease progression. After 12 months, 60% of patients with primary lung cancer and 35% of patients with pulmonary metastases were without systemic progression. No severe acute or late toxicity was observed, and only 2 patients (3%) developed symptomatic Grade 2 pneumonitis, which was successfully treated with oral steroids. CONCLUSION: Stereotactic radiotherapy for lung tumors offers a very effective treatment option locally without significant complications in medically impaired patients who are not amenable to surgery. Patient selection is important, because those with a low risk of systemic progression are more likely to benefit from this approach.

Adult↗
PubMed2004

Cell type-specific association of hypoxia-inducible factor-1 alpha (HIF-1 alpha) protein accumulation and radiobiologic tumor hypoxia.

PURPOSE: The transcription factor subunit hypoxia-inducible factor-1 alpha (HIF-1 alpha) is currently discussed as a potential endogenous marker of tumor hypoxia to select patients for modified treatment. Despite an association of immunohistochemical HIF-1 alpha overexpression and poor prognosis after radiotherapy in many tumor entities, the reported pattern of HIF-1 alpha staining was often not consistent with tumor hypoxia. To explain this discrepancy, we studied the in vitro conditions under which HIF-1 alpha protein accumulates. METHODS AND MATERIALS: FaDu human pharyngeal carcinoma and HT 1080 human fibrosarcoma cells were treated with different schedules of in vitro hypoxia at 5%, 1%, and 0.1% O(2) and reoxygenation. HIF-1 alpha protein levels were determined in nuclear extracts. Cellular radiation sensitivity was assessed by clonogenic survival assay after single-dose irradiation at the above oxygen concentrations. RESULTS: In both cell lines, weak HIF-1 alpha expression was observed at 20% O(2) and after 10 min of hypoxia. Increased HIF-1 alpha protein levels were observed at 1 h of hypoxia, remained stable over 24 h, and decreased to baseline within 15 min of reoxygenation. HIF-1 alpha protein at 5% O(2) was half-maximal in FaDu but indistinguishable from 0.1% O(2) in HT 1080. A good correlation of HIF-1 alpha protein level and hypoxic radiation resistance, with equal ranking of data points by both assays, was observed in FaDu cells but not in HT 1080 cells. CONCLUSIONS: The ability of HIF-1 alpha to indicate radiobiologically relevant levels of tumor hypoxia seems to be cell type specific. This finding may explain the inconsistent results regarding the pattern of HIF-1 alpha expression in tumor sections.

Cell Hypoxia↗
PubMed2004

Inversion recovery TrueFISP: quantification of T(1), T(2), and spin density.

A novel procedure is proposed to extract T(1), T(2), and relative spin density from the signal time course sampled with a series of TrueFISP images after spin inversion. Generally, the recovery of the magnetization during continuous TrueFISP imaging can be described in good approximation by a three parameter monoexponential function S(t) = S(stst)(1-INV exp(-t/T(*) (1)). This apparent relaxation time T(*) (1) <or= T(1) depends on the flip angle as well as on both T(1) and T(2). Here, it is shown that the ratio T(1)/T(2) can be directly extracted from the inversion factor INV, which describes the relation of the signal value extrapolated to t = 0 and the steady-state signal. Analytical expressions are given for the derivation of T(1), T(2), and relative spin density directly from the fit parameters. Phantom results show excellent agreement with single point reference measurements. In human volunteers T(1), T(2), and spin density maps in agreement with literature values were obtained.

Algorithms↗
PubMed2004

Recurrent rectal cancer within the pelvis. A multicenter analysis of 123 patients and recommendations for adjuvant radiotherapy.

BACKGROUND AND PURPOSE: Recommendations for radiation ports in adjuvant radiation therapy for rectal cancer are mainly based on analysis of recurrence patterns. To evaluate whether changes in surgical technique have influenced this pattern of recurrence, a multicenter retrospective analysis was carried out on a patient population treated recently. PATIENTS AND METHODS: 123 patients were evaluated with the help of a CT-based self-developed 3-D data file system and an extensive questionnaire. Major inclusion criteria (one sufficient) for eligibility were: histological confirmation, clear bone destruction, and a positive PET scan, or at least three minor criteria: progressive soft tissue mass, invasion of adjacent organs on follow-up CT or MRI, rising tumor markers, and typical appearance in cross-sectional imaging. Clinical or serologic signs of inflammation were exclusion criteria. RESULTS: Initially, 54% of the evaluated patients were N0; in the remainder, N1 and N2 were distributed evenly. Initial T-category was T1 in 2%, T2 in 24%, T3 in 60%, and T4 in 13%, the male-to-female ratio was 2:1. Recurrent tumors were mainly situated in the posterior part of the bony pelvis as displayed in the figures. When abdominoperineal resection was compared to low anterior resection as primary operation, there was a significant difference in extension of recurrent tumors in the inferior parts of the pelvis (p<0.025 in all statistical tests applied), whereas no significant difference was found in the superior parts of the pelvis. CONCLUSION: Based on these results, a modest field size reduction in adjuvant radiotherapy for rectal cancer seems feasible, offering the perspective of a reduction in acute and late side effects.

Adult↗
PubMed2004

Outcome of postoperative treatment for rectal cancer UICC stage II and III in day-to-day clinical practice. Results from a retrospective quality control analysis in six institutions in North Bavaria (Germany).

BACKGROUND AND PURPOSE: Radiochemotherapy (RChT) as adjuvant treatment for rectal cancer UICC stage II/III has been recommended by the National Cancer Institute (NCI) since 1991 and in Germany since 1994. Quality and results of postoperative treatment in day-to-day clinical practice in a complete region are evaluated retrospectively in a multi-institutional approach. PATIENTS AND METHODS: 534 patients from six institutions treated between 1993 and 1998 were evaluated. The institutions covered a complete region with radiotherapeutic care. Patients were staged as follows: UICC I 1%, II 28%, III 69%, and IV 2%. 92% received RChT, 8% radiotherapy (RT) alone. Median follow-up of patients was 47 months (17-91 months). RESULTS: Only about 37% of expected patients were referred for postoperative treatment. The 5-year actuarial rate was as follows: local control 75% (63-84%), freedom from distant metastases 56% (44-63%), disease-free survival (DFS) 53% (42-59%), and overall survival (OS) 53% (45-64%). In multivariate analysis, local control was significantly influenced by T- and N-category, tumor grading, and RChT instead of RT alone. 6% (2-11%) of patients showed involved resection margins, in 33% of patients categorized pN0 less than the required twelve lymph nodes were examined, both leading to a significant decrease of local control. CONCLUSION: While the quality of adjuvant treatment followed consensus guidelines, the number of referred patients which was lower as expected and the inferior treatment results as compared to randomized studies indicate that the consensus recommendations for adjuvant treatment have not been fully accepted. Instead of patient referral according to UICC stage, patient selection by the surgeons has been performed according to individual risk factors. Efforts have to be made not only to improve treatment results in randomized studies but also to transfer and control these standards in daily practice.

Actuarial Analysis↗