Background & purpose: Involved internal iliac and obturator lateral lymph nodes (LLNs) are a known risk factor for ipsi-lateral local recurrences (LLR) in rectal cancer. This study examined... Show moreBackground & purpose: Involved internal iliac and obturator lateral lymph nodes (LLNs) are a known risk factor for ipsi-lateral local recurrences (LLR) in rectal cancer. This study examined coverage of LLNs with routine radiotherapy practice in the Netherlands and associated LLR rates. Materials & methods: Patients with a primary tumor ≤8cm of the anorectal junction, cT3-4 stage and at least one internal iliac or obturator LLN with short-axis ≥5mm who received neoadjuvant (chemo)radiotherapy, were selected from a national, cross-sectional study of rectal cancer patients treated in the Netherlands in 2016. MR-images and radiotherapy treatment plans were reviewed regarding segmented LLNs as gross-tumor volume (GTV), location of LLNs within clinical target volume (CTV), and received proportion of the planned radiotherapy dose. Results: A total of 223 out of 3057 patients with at least one LLN ≥5mm were selected. Of those, 180 (80.7%) LLNs were inside the CTV, of which 60 (33.3%) were segmented as GTV. Overall, 202 LLNs (90.6%) received >95% of the planned dose. Four-year LLR rates were not significantly higher for LLNs situated outside the CTV compared to inside (4.0% vs. 12.5%, p=.092) or when receiving <95% versus >95% of the planned radiotherapy dose (7.1% vs. 11.3%, p=.843), respectively. Two of seven patients who received a dose-escalation of 60Gy developed a LLR (4-year LLR rate 28.6%). Conclusion: This evaluation of routine radiotherapy practice showed that adequate coverage of LLNs was still associated with considerable 4-year LLR rates. Techniques resulting in better local control for patients with involved LLNs need to be explored further. Show less
Ende, R.P.J. van den; Peters, F.P.; Harderwijk, E.; Rutten, H.; Bouwmans, L.; Berbee, M.; ... ; Kerkhof, E.M. 2020
Background The STAR-TReC trial is an international multi-center, randomized, phase II study assessing the feasibility of short-course radiotherapy or long-course chemoradiotherapy as an alternative... Show moreBackground The STAR-TReC trial is an international multi-center, randomized, phase II study assessing the feasibility of short-course radiotherapy or long-course chemoradiotherapy as an alternative to total mesorectal excision surgery. A new target volume is used for both (chemo)radiotherapy arms which includes only the mesorectum. The treatment planning QA revealed substantial variation in dose to organs at risk (OAR) between centers. Therefore, the aim of this study was to determine the treatment plan variability in terms of dose to OAR and assess the effect of a national study group meeting on the quality and variability of treatment plans for mesorectum-only planning for rectal cancer. Methods Eight centers produced 25 x 2 Gy treatment plans for five cases. The OAR were the bowel cavity, bladder and femoral heads. A study group meeting for the participating centers was organized to discuss the planning results. At the meeting, the values of the treatment plan DVH parameters were distributed among centers so that results could be compared. Subsequently, the centers were invited to perform replanning if they considered this to be necessary. Results All treatment plans, both initial planning and replanning, fulfilled the target constraints. Dose to OAR varied considerably for the initial planning, especially for dose levels below 20 Gy, indicating that there was room for trade-offs between the defined OAR. Five centers performed replanning for all cases. One center did not perform replanning at all and two centers performed replanning on two and three cases, respectively. On average, replanning reduced the bowel cavity V20Gy by 12.6%, bowel cavity V10Gy by 22.0%, bladder V35Gy by 14.7% and bladder V10Gy by 10.8%. In 26/30 replanned cases the V10Gy of both the bowel cavity and bladder was lower, indicating an overall lower dose to these OAR instead of a different trade-off. In addition, the bowel cavity V10Gy and V20Gy showed more similarity between centers. Conclusions Dose to OAR varied considerably between centers, especially for dose levels below 20 Gy. The study group meeting and the distribution of the initial planning results among centers resulted in lower dose to the defined OAR and reduced variability between centers after replanning. Show less
Background The optimal treatment sequence for patients with rectal cancer and synchronous liver metastases remains unclear. The aim of this study was to evaluate the feasibility and effectiveness... Show moreBackground The optimal treatment sequence for patients with rectal cancer and synchronous liver metastases remains unclear. The aim of this study was to evaluate the feasibility and effectiveness of short-course pelvic radiotherapy (5 x 5 Gy) followed by systemic therapy and local treatment of all tumour sites in patients with potentially curable stage IV rectal cancer in daily practice.Methods This was a retrospective study performed in eight tertiary referral centres in the Netherlands. Patients aged 18 years or above with rectal cancer and potentially resectable liver +/- extrahepatic metastases, treated between 2010 and 2015, were eligible. Main outcomes included full completion of treatment schedule, symptom control and survival.Results In total, 169 patients were included with a median follow-up of 49 center dot 5 (95 pr cent c.i. 43 center dot 6 to 55 center dot 6) months. The completion rate for the entire treatment schedule was 65 center dot 7 per cent. Three-year progression-free survival and overall survival (OS) rates were 24 center dot 2 (95 per cent c.i. 16 center dot 6 to 31 center dot 6) and 48 center dot 8 (40 center dot 4 to 57 center dot 2) per cent respectively. Median OS of patients who responded well and completed the treatment schedule was 51 center dot 5 months, compared with 15 center dot 1 months for patients who did not complete the treatment (P < 0 center dot 001). Adequate symptom control of the primary tumour was achieved in 87 center dot 0 per cent of all patients.Conclusion Multimodal treatment is palliative in most patients, and associated with good survival rates in those able to complete the schedule. Show less
Stijns, R.C.H.; Graaf, E.J.R. de; Punt, C.J.A.; Nagtegaal, I.D.; Nuyttens, J.J.M.E.; Meerten, E. van; ... ; CARTS Study Grp 2019
Purpose: To assess the effect of additional magnetic resonance imaging (MRI) alongside the planning computed tomography (CT) scan on target volume delineation in pancreatic cancer patients.Material... Show morePurpose: To assess the effect of additional magnetic resonance imaging (MRI) alongside the planning computed tomography (CT) scan on target volume delineation in pancreatic cancer patients.Material and methods: Eight observers (radiation oncologists) from six institutions delineated the gross tumor volume (GTV) on 3DCT, and internal GTV (iGTV) on 4DCT of four pancreatic cancer patients, while MRI was available in a second window (CT+MRI). Variations in volume, generalized conformity index (CIgen), and overall observer variation, expressed as standard deviation (SD) of the distances between delineated surfaces, were analyzed. CIgen is a measure of overlap of the delineated iGTVs (1=full overlap, 0=no overlap). Results were compared with those from an earlier study that assessed the interobserver variation by the same observers on the same patients on CT without MRI (CT-only).Results: The maximum ratios between delineated volumes within a patient were 6.1 and 22.4 for the GTV (3DCT) and iGTV (4DCT), respectively. The average (root-mean-square) overall observer variations were SD=0.41cm (GTV) and SD=0.73cm (iGTV). The mean CIgen was 0.36 for GTV and 0.37 for iGTV. When compared to the iGTV delineated on CT-only, the mean volumes of the iGTV on CT+MRI were significantly smaller (32%, Wilcoxon signed-rank, p<.0005). The median volumes of the iGTV on CT+MRI were included for 97% and 92% in the median volumes of the iGTV on CT. Furthermore, CT+MRI showed smaller overall observer variations (root-mean-square SD=0.59cm) in six out of eight delineated structures compared to CT-only (root-mean-square SD=0.72cm). However, large local observer variations remained close to biliary stents and pathological lymph nodes, indicating issues with instructions and instruction compliance.Conclusions: The availability of MRI images during target delineation of pancreatic cancer on 3DCT and 4DCT resulted in smaller target volumes and reduced the interobserver variation in six out of eight delineated structures. Show less
Bastiaannet, E.; Breugom, A.; Kiderlen, M.; Iversen, L.; Martling, A.; Johansson, R.; ... ; Velde, C. van de 2015
