Prognostic implications of lateral lymph nodes in rectal cancer: a population-based cross-sectional study with standardized radiological evaluation after dedicated training

Background: There is an ongoing discussion regarding the prognostic implications of the presence, short-axis diameter and location of lateral lymph nodes.Objective: To analyze lateral lymph node characteristics, the role of downsizing on restaging MRI and associated local recurrence rates for patients with cT3-4 rectal cancer after MRI re-review and training.Design: Retrospective population-based cross-sectional study. Settings: This collaborative project was led by local investigators from surgery and radiology departments in 60 Dutch hospitals.Patients: 3057 patients underwent rectal cancer surgery in 2016: 1109 had cT3-4 tumor located ≤8cm from the anorectal junction of which 890 received neoadjuvant therapy. Interventions(s):  NoneMain Outcome Measures: local recurrence and ipsi-lateral local recurrence rates. Results: Re-review identified 314 patients (35%) with visible lateral lymph nodes. 30 of these patients had either only long-stretched obturator (n=13) or external iliac (n=17) nodes and both did not lead to any lateral local recurrences. The presence of internal iliac/obturator lateral lymph nodes (n=284) resulted in 4-year local recurrence and lateral local recurrence rates of 16.4% and 8.8%, respectively. Enlarged (≥7mm) lateral lymph nodes (n=122) resulted in higher 4-year local recurrence (20.8%, 13.1%, 0%, pLimitations: This study was limited by the retrospective design and total number of patients with lateral lymph nodes.Conclusions: The risk of lateral local recurrence due to (enlarged) lateral lymph nodes was confirmed, but without prognostic impact of downsizing after neoadjuvant therapy. These results point towards the incorporation of primary lateral lymph node size into treatment planning. Biological, physical and clinical aspects of cancer treatment with ionising radiatio

Retrospective evaluation of national MRI reporting quality for lateral lymph nodes in rectal cancer patients and concordance with prospective re-evaluation following additional training

Objectives The presence and size of lateral lymph nodes (LLNs) are important factors influencing treatment decisions for rectal cancer. Awareness of the clinical relevance and describing LLNs in MRI reports is therefore essential. This study assessed whether LLNs were mentioned in primary MRI reports at a national level and investigated the concordance with standardised re-review. Methods This national, retrospective, cross-sectional cohort study included 1096 patients from 60 hospitals treated in 2016 for primary cT3-4 rectal cancer = 7 mm) LLNs were not mentioned in primary MRI reports. A contradictory anatomical location was stated for 73.2% of all LLNs and a different size (>=/< 7 mm) for 41.7%. In total, 49.4% of all cases did not mention LLNs in primary MRI reports. Reporting LLNs was associated with stage (cT3N0 44.3%, T3N+/T4 52.8%, p = 0.013), cN stage (N0 44.1%, N1 48.6%, N2 59.5%, p < 0.001), hospital type (non-teaching 34.6%, teaching 52.2%, academic 53.2% p = 0.006) and annual rectal cancer resection volumes (low 34.8%, medium 47.7%, high 57.3% p < 0.001). For LLNs present according to original MRI reports (n = 226), 64.2% also mentioned a short-axis size, 52.7% an anatomical location and 25.2% whether it was deemed suspicious. Conclusions Almost half of the primary MRI reports for rectal cancer patients treated in the Netherlands in 2016 did not mention LLNs. A significant portion of enlarged LLNs identified during re-review were also not mentioned originally, with considerable discrepancies for location and size. These results imply insufficient awareness and indicate the need for templates, education and training

Coverage of lateral lymph nodes in rectal cancer patients with routine radiotherapy practice and associated locoregional recurrence rates

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 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% 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. </p