PubMed Health⌕ Search

Biomedical subjects

Kurt Baier

Publications and source records attributed to Kurt Baier.

18 recordsLinked to original sources
PubMed2006

Distinct effects of rectum delineation methods in 3D-conformal vs. IMRT treatment planning of prostate cancer.

BACKGROUND: The dose distribution to the rectum, delineated as solid organ, rectal wall and rectal surface, in 3D conformal (3D-CRT) and intensity-modulated radiotherapy treatment (IMRT) planning for localized prostate cancer was evaluated. MATERIALS AND METHODS: In a retrospective planning study 3-field, 4-field and IMRT treatment plans were analyzed for ten patients with localized prostate cancer. The dose to the rectum was evaluated based on dose-volume histograms of 1) the entire rectal volume (DVH) 2) manually delineated rectal wall (DWH) 3) rectal wall with 3 mm wall thickness (DWH(3)) 4) and the rectal surface (DSH). The influence of the rectal filling and of the seminal vesicles' anatomy on these dose parameters was investigated. A literature review of the dose-volume relationship for late rectal toxicity was conducted. RESULTS: In 3D-CRT (3-field and 4-field) the dose parameters differed most in the mid-dose region: the DWH showed significantly lower doses to the rectum (8.7% +/- 4.2%) compared to the DWH(3) and the DSH. In IMRT the differences between dose parameters were larger in comparison with 3D-CRT. Differences were statistically significant between DVH and all other dose parameters and between DWH and DSH. Mean doses were increased by 23.6% +/- 8.7% in the DSH compared to the DVH in the mid-dose region. Furthermore, both the rectal filling and the anatomy of the seminal vesicles influenced the relationship between the dose parameters: a significant correlation of the difference between DVH and DWH and the rectal volume was seen in IMRT treatment. DISCUSSION: The method of delineating the rectum significantly influenced the dose representation in the dose-volume histogram. This effect was pronounced in IMRT treatment planning compared to 3D-CRT. For integration of dose-volume parameters from the literature into clinical practice these results have to be considered.

Dose-Response Relationship, Radiation↗
PubMed2006

Magnitude and clinical relevance of translational and rotational patient setup errors: a cone-beam CT study.

PURPOSE: To establish volume imaging using an on-board cone-beam CT (CB-CT) scanner for evaluation of three-dimensional patient setup errors. METHODS AND MATERIALS: The data from 24 patients were included in this study, and the setup errors using 209 CB-CT studies and 148 electronic portal images were analyzed and compared. The effect of rotational errors alone, translational errors alone, and combined rotational and translational errors on target coverage and sparing of organs at risk was investigated. RESULTS: Translational setup errors using the CB-CT scanner and an electronic portal imaging device differed <1 mm in 70.7% and <2 mm in 93.2% of the measurements. Rotational errors >2 degrees were recorded in 3.7% of pelvic tumors, 26.4% of thoracic tumors, and 12.4% of head-and-neck tumors; the corresponding maximal rotational errors were 5 degrees , 8 degrees , and 6 degrees . No correlation between the magnitude of translational and rotational setup errors was observed. For patients with elongated target volumes and sharp dose gradients to adjacent organs at risk, both translational and rotational errors resulted in considerably decreased target coverage and highly increased doses to the organs at risk compared with the initial treatment plan. CONCLUSIONS: The CB-CT scanner has been successfully established for the evaluation of patient setup errors, and its feasibility in day-to-day clinical practice has been demonstrated. Our results have indicated that rotational errors are of clinical significance for selected patients receiving high-precision radiotherapy.

Head and Neck Neoplasms↗
PubMed2006

Adverse effect of a distended rectum in intensity-modulated radiotherapy (IMRT) treatment planning of prostate cancer.

BACKGROUND AND PURPOSE: The retrospective planning study for intensity-modulated radiotherapy (IMRT) of prostate cancer evaluated whether proximal rectum and supra-anal rectum/anal canal should be delineated as separated organs-at-risk (OARs) to achieve optimal dose distributions to the anorectal region. PATIENTS AND METHODS: For 10 patients with localized prostate cancer IMRT plans were generated with the rectum and anal canal as separated OARs (Rec-sep) and as one single OAR (Rec-tot). Two different treatment planning systems (TPS) were utilized. Influence on dose distributions to target and OARs was analyzed. RESULTS: Results from both TPS showed significantly increased doses to the distal rectum/anal canal for plans Rec-tot compared with Rec-sep in case of a distended rectum in the planning CT study: doses were increased by up to mean 31% (P = 0.02) and 18% (P = 0.03), respectively, in both TPS. For the patient with the largest rectum, the maximum dose increase was 61%. No significant differences in doses to target, bladder, femoral head and proximal rectum were seen. CONCLUSIONS: For patients with a distended rectum in the planning CT, delineation of separated OARs for proximal rectum and distal rectum/anal canal resulted in superior dose distributions to the anorectal region and therefore, we recommend this as standard procedure for IMRT planning of prostate cancer.

Algorithms↗
PubMed2006

Influence of rectum delineation (rectal volume vs. rectal wall) on IMRT treatment planning of the prostate.

PURPOSE: To evaluate the delineation of either the rectal volume (RV) or the rectal wall (RW) in intensity-modulated radiotherapy (IMRT) for prostate cancer: influence on dose distribution to the targets and organs at risk (OARs) was investigated. MATERIAL AND METHODS: For ten patients with localized prostate cancer IMRT treatment plans were generated with the RV, wall including the filling, and the RW without the lumen as OAR (plan-RV and plan-RW), respectively. Two different IMRT treatment- planning systems (TPS) were utilized. The influence on target coverage and sparing of OARs was investigated. RESULTS: No influence was seen on target coverage and sparing of the bladder and femoral heads. Doses to the RV were significantly reduced in plan-RV for all evaluated dose levels: maximum 26% and 17%, respectively, in both TPS. The dose distribution to the RW was not significantly different between plan-RV and plan-RW. CONCLUSION: The different delineation of the OAR rectum significantly affected the inverse IMRT treatment-planning process. The use of the RV as OAR resulted in improved dose distributions to the RV. Therefore, it is suggested using the RV as OAR in IMRT treatment planning of the prostate.

Femur Head↗
PubMed2006

3-D conformal treatment of prostate cancer to 74 Gy vs. high-dose-rate brachytherapy boost: a cross-sectional quality-of-life survey.

The effects of two modalities of dose-escalated radiotherapy on health-related quality of life (HRQOL) were compared. Forty-one consecutive patients were treated with a 3-D conformal (3-DC) boost to 74 Gy, and 43 with high-dose rate (HDR) brachytherapy boost (2x9 Gy), following 3-D conformal treatment to 46 Gy. Median age was 70 years in both groups, median initial PSA was 7.9 microg/l in 3-DC boost patients and 8.1 microg/l in HDR boost patients. Stage was or=7 in 52% and 47%, respectively. HRQOL was assessed cross-sectionally using EORTC QLQ-C30 and organ-specific PR25 modules 3--32 (median 19) and 4--25 (median 14) months after treatment, respectively. Questionnaires were completed by 93% and 97% of patients, respectively. Diarrhea and insomnia scores were significantly increased in both groups. In the PR25 module, scores of 3-DC boost and HDR boost patients for urinary, bowel and treatment-related symptoms were similar. Among responders, 34% of 3-DC boost patients and 86% of HDR boost patients had severe erectile problems. Dose escalation in prostate cancer by either 3-DC boost to 74 Gy or HDR brachytherapy boost appears to result in similar HRQOL profiles.

Brachytherapy↗
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

Dose-response in stereotactic irradiation of lung tumors.

The dose-response for local tumor control after stereotactic radiotherapy of 92 pulmonary tumors (36 NSCLC and 56 metastases) was evaluated. Short course irradiation of 1-8 fractions with different fraction doses was used. After a median follow-up of 14 months (2-85 months) 11 local recurrences were observed with significant advantage for higher doses. When normalization to a biologically effective dose (BED) is used a dose of 94Gy at the isocenter and 50Gy at the PTV-margin are demonstrated to give 50% probability of tumor control (TCD50). Multivariate analysis revealed the dose at the PTV-margin as the only significant factor for local control.

Carcinoma, Non-Small-Cell Lung↗
PubMed2005

Fast image acquisition and processing on a TV camera-based portal imaging system.

The present paper describes the fast acquisition and processing of portal images directly from a TV camera-based portal imaging device (Siemens Beamview Plus). This approach employs not only hard- and software included in the standard package installed by the manufacturer (in particular the frame grabber card and the Matrox Intellicam interpreter software), but also a software tool developed in-house for further processing and analysis of the images. The technical details are presented, including the source code for the Matrox interpreter script that enables the image capturing process. With this method it is possible to obtain raw images directly from the frame grabber card at an acquisition rate of 15 images per second. The original configuration by the manufacturer allows the acquisition of only a few images over the course of a treatment session. The approach has a wide range of applications, such as quality assurance (QA) of the radiation beam, real-time imaging, real-time verification of intensity-modulated radiation therapy (IMRT) fields, and generation of movies of the radiation field (fluoroscopy mode).

Humans↗
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

Positional variability of a tandem applicator system in HDR brachytherapy for primary treatment of cervix cancer. Analysis of the anatomic pelvic position and comparison of the applicator positions during five insertions.

PURPOSE: Evaluation of the inter- and intraindividual applicator variability of multiple high-dose-rate (HDR) brachytherapy applications for primary treatment of cancer of the uterine cervix. MATERIAL AND METHODS: Retrospective analysis of 460 pairs of orthogonal X-ray films for conventional treatment in 92 patients with five intrauterine applications using an HDR tandem applicator. Measurement of the position of the applicator origin relative to a bony reference system in three dimensions. Evaluation of the differences of the applicator position in all 460 applications (interindividual variability), of the five applications in a single patient (intraindividual variability) and of the intraindividual variability relative to the applicator position at the first application. RESULTS: The position of the applicator origin in the pelvis ranged from 23 mm cranial and 55 mm caudal to the top of femoral heads, 23 mm right and 27 mm left to the pelvic midline, and 6-53 mm dorsal to the mid of the femoral heads. Standard deviation (SD) of interindividual applicator variability was 12.9 mm (minimum/maximum -55/+23 mm, mean -13.6 mm) in longitudinal, 5.1 mm (-27/+23 mm, mean 1.6 mm) in lateral, and 7.6 mm (6/53 mm, mean 26 mm) in anterior-posterior [AP] direction. SD of intraindividual variability was 5.5 mm (-21/+23 mm, mean 0 mm) in longitudinal, 2.5 mm (-17/+19 mm, mean 0 mm) in lateral, and 4.2 mm (-15/+18 mm, mean 0 mm) in AP direction compared to intraindividual variability relative to the first insertion with an SD of 8.9 mm (-23/+36 mm, mean 2.8 mm) in longitudinal, 4.0 mm (-11/+23 mm, mean 0 mm) in lateral, and 6.8 mm (-27/+17 mm, mean -0.8 mm) in AP direction. CONCLUSION: Intraindividual applicator variability is significantly smaller than interindividual variability. Applicator-related procedures such as midline shielding or dose matching of tele- and brachytherapy should be performed with information on at least one individual applicator position.

Adenocarcinoma↗
PubMed2004

A table top suited for CT and radiotherapy.

A radiotherapy table top was to be designed and manufactured, suitable for computer tomography in the same room. The aim was a distortion of the dose distribution by the table top of not more than 4% in small subunits of the target volume (TV) and less than 2% for the mean dose in the TV. Only negligible artifacts in the CT slices should occur in order to assure the exact relocalization of the TV. The table top manufactured of carbon fiber reinforced plastic was constructed by means of finite-element-algorithms. The trapezoidal shaped sandwich plate is supported with tapered beams. The small side of the table can penetrate a 60 cm CT-gantry. When turned, the table top allows large ap-pa opposed fields without irradiating through the beams. Transmission measurements were performed with an ionization chamber under different irradiation angles to determine the influence of the beams and the covering plate. Additionally, a portal imaging device (PID) was used for comparison. It was found that the deflection and torsion of the carbon fiber table top was smaller than for the original. The transmission of the sandwich plate was 97.5% (18 MV) and 96.5% (6 MV photons) respectively. If the irradiation of the beam walls can not be avoided the transmission is not in a critical range. The CT-slices show only minor artifacts along the side walls of the beams. The localization of the tumor or the TV is not restricted.

Artifacts↗
PubMed2003

A little to a lot or a lot to a little? An analysis of pneumonitis risk from dose-volume histogram parameters of the lung in patients with lung cancer treated with 3-D conformal radiotherapy.

PURPOSE: To determine whether a little dose to a large normal lung volume or a high dose to a small lung volume is more critical for induction of clinical pneumonitis. The second question is if dose-volume histogram (DVH) parameters are more reliable, if the lungs are analyzed as separate organs or as a whole organ. PATIENTS AND METHODS: We analyzed the clinical and DVH data from 49 patients treated for a thoracic malignancy using 3-D conformal treatment plans. 18 patients had developed a clinical pneumonitis (CTC II or III). The majority of patients (n = 48) received radiochemotherapy for non-small-cell lung cancer (NSCLC) with a combination of paclitaxel and carboplatin. Patients were generally treated 5 fx/week, single dose 2 Gy, using a two-series approach (shrinking field) up to a total dose of 60-70 Gy. For every individual patient, the overall dose distribution was recalculated in the Helax-TMS by means of adding dose plans according to the total dose applied in each series. The lungs were defined both as separate organs and as a whole organ. Low-dose volume (< or = 10 Gy, Vlow), moderate-dose volume (> 10-40 Gy, Vmod) and high-dose volume (> 40 Gy, Vhigh), as well as V10-V40 and mean lung dose (MLD) were defined from the cumulative DVH. Dose-effect relationships were fitted with a logistic regression model. RESULTS: Manifestation of clinical pneumonitis was within 3 months from termination of irradiation in all cases. For the ipsilateral lung, the incidence of pneumonitis was closely correlated to Vhigh. The pneumonitis rate increased from 13% up to 60%. By contrast, with increasing Vlow the pneumonitis rate dropped to < 10%. A similar but less pronounced effect was seen for the total lung. The lung volumes Vlow, Vmod and Vhigh of the ipsilateral, contralateral and whole lung were significantly correlated to the corresponding MLD. The incidence of pneumonitis increased with increasing MLD for the ipsilateral lung with a D50 of 32 Gy and a gamma 50 of 0.98. For the whole lung, the observed increase was less steep. MLD showed a close correlation to NTCP calculated by the Kutcher model. However, NTCP calculation overestimated the pneumonitis risk for the ipsilateral lung and underestimated the risk for the whole lung due to the steeper gradient. The logistic regression curve for the DVH parameters V10-V40 showed an increase of steepness toward higher doses. From the logistic regression curves, a DVH template indicating critical borders of V10-V40 was generated for the ipsilateral as well as for the total lung. CONCLUSION: Our data indicate that it is reasonable to disperse the dose outside the target volume over large areas in order to reduce the volumes of lung receiving > 40 Gy. Reducing the high-dose volume reduces the pneumonitis rate more than a corresponding reduction in the low-dose regions of the DVH. Landmarks for DVH optimization as defined in this analysis may serve as a basis for DVH contrains in IMRT planning. Separate organ analysis produced more reliable results and should be preferred to whole-organ analysis, if techniques mainly involving one side of the lung are applied. Further validation of these constraints is necessary prior to general recommendation.

Aged↗
PubMed2002

Dose, volume, and tumor control prediction in primary radiotherapy of non-small-cell lung cancer.

BACKGROUND: To evaluate the influence of total dose and tumor volume on local control and survival in primary radiotherapy of non-small-cell lung cancer (NSCLC). METHODS AND MATERIALS: We retrospectively analyzed the clinical course and CT-derived pre- and post-therapeutic tumor volume data of 135 patients with NSCLC undergoing primary radiotherapy at our department between 1989 and 1996. Among these, a total of 192 spatially separated tumor volumes (135 primary tumors, 1 additional intrapulmonary tumor, and 56 involved lymph nodes) were available for analysis. In all patients, treatment was planned using CT-based three-dimensional treatment planning. The dose to each tumor volume was derived from the individual dose plans. Mean total dose was 59.9 Gy (range: 30-80 Gy). All but 3 patients were followed until death. For local control analysis, each tumor was analyzed separately, and its remission status was determined in serial follow-up CT scans. A total of 784 CT scans were analyzed. Actuarial local control analysis was performed for the 192 separated tumor volumes, and survival analysis was performed for the 135 patients. Tumor control probability was calculated using a Poisson statistical model. RESULTS: Overall 1- and 2-year local control rate was 50% and 37%, respectively. The 2-year local control rate for tumors <50 ccm, 50-200 ccm, and >200 ccm was 51%, 22%, and 10%, respectively (p = 0.02). The 2-year local control rate for dose levels < or = 60 Gy and >60 Gy was 28% and 43% (p < 0.001). For the subgroup of 147 tumors smaller than 100 ccm, the local control rate increased up to 70% (1 year) and 51% (2 years) with doses of more than 60 Gy. For tumors larger than 100 ccm, no dose effect was seen. Only 2 of 45 tumors >100 ccm were controlled more than 2 years. Multivariate analysis revealed tumor volume, total dose, histopathologic type, and grading as significant and independent prognostic factors for local control. The number of delay days by split course (if used) and application of chemotherapy was not found to influence local control. Overall 1- and 2-year survival rate was 42% and 13%. Total radiation dose, chemotherapy, and T and N stage---but not tumor volume---were found to be independent and significant prognostic factors for survival in multivariate analysis. CONCLUSION: Tumor volume is an important predictor of local control in NSCLC. We found a clear dose effect for local control and survival in NSCLC. Long-term local control for a significant proportion of patients seems possible for small tumors only (<100 ccm, i.e., maximum diameter 6 cm) with doses of 70 Gy and more. Tumors of > or = 100 ccm are unlikely to be controlled long term by conventional doses up to 70 Gy. These results support dose escalation in patients with NSCLC.

Adenocarcinoma↗