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K. De Jaeger
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MINI 37 - SCLC Therapy (ID 165)
- Event: WCLC 2015
- Type: Mini Oral
- Track: Small Cell Lung Cancer
- Presentations: 1
- Moderators:D. Ettinger, G.R. Simon
- Coordinates: 9/09/2015, 18:30 - 20:00, 605+607
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MINI37.11 - Inter-Observer Variability in Hippocampus Delineation on MRI Scans for Hippocampal Avoidance Prophylactic Cranial Irradiation Trial (ID 2620)
19:30 - 19:35 | Author(s): K. De Jaeger
- Abstract
- Presentation
Background:
Prophylactic cranial irradiation (PCI) is the standard treatment in patients with small-cell lung cancer (SCLC) without progression after chemo-radiotherapy in stage I-III disease and after having a remission after chemotherapy in stage IV. In an international phase III trial (NCT01780675), patients with SCLC are randomised to receive PCI with or without Hippocampal Avoidance (HA). Accurate delineation of the hippocampus is crucial for this trial. In this study we evaluate the hippocampus delineation variability among radiation oncologists in multi-institutions for SCLC patients.
Methods:
The left and right hippocampus from 5 randomly selected patients (10 structures) were delineated by 5 radiation oncologists and 2 neuroradiologist in 7 institutions according to the RTOG atlas (http://www.rtog.org/CoreLab/ContouringAtlases/HippocampalSparing.aspx), together with a questionnaire. For each patient, a high resolution 3D inversion recovery T1 weighted MRI-scan was first registered to the planning CT-scan (1mm slicing). The observer then delineated the hippocampus according to the atlas on axial slices of the MRI. The mapped delineations on the CT were then used in dose planning with a 5mm margin. The mean and standard deviation (SD) of 1) volume and 2) range in medio-lateral, superior-inferior and anterior-posterior directions were computed for each structure. The corresponding inter-observer reliability was estimated by the intra-class correlation coefficient (ICC absolute agreement) using a linear mixed model. A median surface was computed and the overall delineation variability per structure was calculated by the root-mean-square (rms) of the local SD per sampled points on the median surface, while the local SD corresponds to the perpendicular distance between each observer and a sampled point.
Results:
The standard deviation of the delineated volume per structure varied from 0.14 to 0.48cm3. The corresponding inter-observer reliability (ICC) was 0.19, implying a high variability among the observers. The overall delineation variability per structure varied from 0.6 to 1.0mm. Areas with good agreements were the superior and inferior part of the hippocampus. The difficult area (Fig.1) was in the anterior medial area, close to the amygdala and uncus. The ICC in medio-lateral, superior-inferior and anterior-posterior directions were 0.55, 0.64 and 0.80, respectively. A large spread of the SD of range in medio-lateral direction and the relative low ICC imply that a better instruction, or training is desirable to improve the delineations. Figure 1
Conclusion:
There was a substantial variability in hippocampus delineation among the observers. Stricter adherence to the RTOG guidelines and (web-based) training are needed. The implication of the variations on the dose distribution is currently verified.
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P1.01 - Poster Session/ Treatment of Advanced Diseases – NSCLC (ID 206)
- Event: WCLC 2015
- Type: Poster
- Track: Treatment of Advanced Diseases - NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 9/07/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P1.01-029 - Dutch Radiotherapy Lung Audit: Results of 2014 (ID 1340)
09:30 - 09:30 | Author(s): K. De Jaeger
- Abstract
Background:
The Dutch Radiotherapy Lung Audit (DLRA) is an outcome registration that provides the local health professionals with an instrument to compare and improve their lung cancer treatments. It ensures transparency regarding clinical outcome, quality and safety of lung cancer treatments in the radiotherapy departments throughout the Netherlands. Patients receiving thoracic radiation treatment with curative intent for (primary or recurrent) stage I-IIIB Non-Small Cell Lung Cancer (NSCLC) were included in the registry. The results of the DLRA on the first fully registered year, 2014, are reported.
Methods:
Information collected included patient, tumor and treatment characteristics, the incidence and severity of acute toxicity, mortality within three months after radical radiation treatment and the time interval between diagnostic work-up and start of the radiotherapy. The adherence to the waiting time (time between referral and start of the irradiation) and throughput time (time between planning CT scan and start of the irradiation) guidelines were registered and analyzed, as well as the use of modern treatment techniques such as stereotactic irradiation and image-guided radiotherapy.
Results:
14 out of 21 radiotherapy institutes included patients in the DLRA database. A total of 1350 patients were entered from January-December 2014. Patients were treated with concurrent (32%) or sequential chemoradiation(20%), radiotherapy only (13%) or stereotactic ablative body radiotherapy (SABR [35%]). On a patient record level, there was a high level of completeness. The mean age was 69 years (range 32-91, 59% males). Charlson comorbidity index ≥ 2 was present in 42% of patients. Most patients (45%) were cN+ with 20% cT4 tumors. Fifty eight percent of all patients started irradiation within 21 days after referral (range 0-89%). For 68% of the patients SABR started within 10 days after the planning-CT scan was acquired (range 17-100%) (fig 1). There was no correlation between the number of patients treated and the throughput times. Most patients received IMRT or VMAT irradiation. All registered patients had position verification during irradiation, mostly 3D (94%). Three-month (calculated from the end of RT) acute esophagus toxicity (grade≥ III) and pneumonitis (grade≥ II) of concurrent treatment were 12.4% and 3.9%, 6.1% and 4.1% for sequential chemoradiation, 3.3% and 4.3% for radiotherapy only, and 0.4% and 2.3% for SABR, respectively. Three-month mortality rates were 8.2%, 8.5%, 9.6%, and 1.7%, respectively. Figure 1
Conclusion:
The Dutch Radiotherapy Lung Audit on outcomes after (chemo)radiotherapy is directed towards an improvement of care for lung cancer patients. There's room for improvement in the waiting and throughput times.
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P2.01 - Poster Session/ Treatment of Advanced Diseases – NSCLC (ID 207)
- Event: WCLC 2015
- Type: Poster
- Track: Treatment of Advanced Diseases - NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 9/08/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P2.01-051 - Determinants of Sequential versus Concurrent Chemoradiotherapy in Stage III Non-Small Cell Lung Cancer Patients (ID 1205)
09:30 - 09:30 | Author(s): K. De Jaeger
- Abstract
Background:
Concurrent chemoradiotherapy (CCRT) is considered the standard treatment regimen in patients with inoperable stage III non-small cell lung cancer (NSCLC). Sequential chemoradiotherapy (SCRT) is recommended in patients who are deemed unfit to receive CCRT. As this selection criterion is not very explicit, the ‘personalized’ choice for either CCRT or SCRT is mainly dependent on the multidisciplinary team and treating physician’s judgment. Consequently, this may result in a variation of treatment policies across hospitals/radiotherapy (RT) departments. In this study, we investigated the ratio CCRT/SCRT in eight RT departments in the Netherlands. Furthermore, we explored which patient and disease characteristics determined the choice for SCRT compared to CCRT.
Methods:
Data were derived from the Dutch Lung Radiotherapy Audit (DLRA). Within the DLRA, lung cancer patients undergoing a curative intent treatment are prospectively registered with respect to patient and disease characteristics, diagnostics and treatment. For this study, from eight out of 21 Dutch RT departments, patients with stage III NSCLC undergoing chemoradiotherapy in 2014 were selected. CCRT was defined as ≤ 50 days between the start of chemotherapy and the start of radiotherapy. Furthermore, RT had to start before the end of the last chemotherapy in CCRT. Patients with < 150 days between treatments were scored as undergoing SCRT. Differences in patient and disease characteristics between CCRT and SCRT were tested with independent samples t-tests (for continuous variables) and with chi-square tests (for categorical variables). A multivariate logistic regression model was constructed to determine patient and disease characteristics associated with the choice for SCRT, using a backward selection procedure. Odds ratios (OR) with 95% confidence intervals (CI) are reported.
Results:
In total, 453 stage III NSCLC patients (mean age 65.4 years, 56.5% male) were registered. Of those, 351 (77.5%) patients underwent CCRT and 102 (22.5%) patients received SCRT. The proportion of patients treated with CCRT ranged from 51% to 89% across RT departments. Gender, smoking, gross target volume (GTV), performance score (PS), lung function, Charlson comorbidity index and tumor location were not significantly associated with SCRT in the multivariate model. Conversely, older age (OR 1.05 [95%CI 1.03-1.09]), histology (large cell carcinoma vs adenocarcinoma [OR 0.42 CI 0.19 to 0.97]) and cN-stage (N3 vs N0-1 [OR 5.71 {95%CI 2.10-15.50}]) were significantly associated with SCRT.
Conclusion:
In this selected group of registered NSCLC patients, a large variation was observed in the proportion of stage III NSCLC patients treated with CCRT, ranging from 51% to 89% across RT departments. Surprisingly, PS and comorbidity index (as indicators of a patients’ physical fitness) were not significantly different in CCRT or SCRT patients while age and cN-stage were. Based on the analyzed patient and disease characteristics, it is currently unclear why patients treated with SCRT were not eligible for CCRT.
