Top Line: A few years back, a study from the Lateral Node Study Consortium found that enlarged (>7mm) lateral pelvic lymph nodes (internal iliac and obturator) had a higher rate of recurrence (19%).
The Study: They also found that persistently enlarged nodes after neoadjuvant therapy had a >50% recurrence rate, which might be mitigated by lateral pelvic lymph node dissection. However, the management of enlarged lateral nodes with either dose escalated radiation or dissection is far from standardized. This Dutch study examined whether standard neoadjuvant doses to the lateral lymph nodes were adequate to control nodal disease. Of over 1200 patients identified with low T3 rectal cancer, 18.2% had internal iliac or obturator nodes measuring ≥5 mm identified retrospectively on MRI. Most of the internal iliac (94.3%) and obturator nodes (78.2%) were included in the original plan CTV, but only 33% were actually delineated as GTV. Most of the nodes outside the CTV (63.4%) still received >95% of the prescribed dose. Most (69.5%) were treated with long-course chemoradiation versus short course RT. At 4 years, the rate of local recurrence was 19.4%, and the rate of lateral pelvic recurrence was 10.8%. Only a small number of patients (3%) received dose escalation to enlarged nodes, yet their rate of lateral node recurrence was 28.6%. In other words, boosting lateral pelvic nodes was uncommon in clinical practice and we can’t draw conclusions from this study about its benefit.
TBL: This retrospective study shows us that nearly 20% of patients with enlarged lateral pelvic nodes experience locoregional recurrence with standard neoadjuvant radiation. While the majority of these nodes are within standard CTVs, we could do a much better job at delineating enlarged nodes to ensure adequate coverage. | Sluckin, Int J Radiat Oncol Biol Phys 2023
The Study: They also found that persistently enlarged nodes after neoadjuvant therapy had a >50% recurrence rate, which might be mitigated by lateral pelvic lymph node dissection. However, the management of enlarged lateral nodes with either dose escalated radiation or dissection is far from standardized. This Dutch study examined whether standard neoadjuvant doses to the lateral lymph nodes were adequate to control nodal disease. Of over 1200 patients identified with low T3 rectal cancer, 18.2% had internal iliac or obturator nodes measuring ≥5 mm identified retrospectively on MRI. Most of the internal iliac (94.3%) and obturator nodes (78.2%) were included in the original plan CTV, but only 33% were actually delineated as GTV. Most of the nodes outside the CTV (63.4%) still received >95% of the prescribed dose. Most (69.5%) were treated with long-course chemoradiation versus short course RT. At 4 years, the rate of local recurrence was 19.4%, and the rate of lateral pelvic recurrence was 10.8%. Only a small number of patients (3%) received dose escalation to enlarged nodes, yet their rate of lateral node recurrence was 28.6%. In other words, boosting lateral pelvic nodes was uncommon in clinical practice and we can’t draw conclusions from this study about its benefit.
TBL: This retrospective study shows us that nearly 20% of patients with enlarged lateral pelvic nodes experience locoregional recurrence with standard neoadjuvant radiation. While the majority of these nodes are within standard CTVs, we could do a much better job at delineating enlarged nodes to ensure adequate coverage. | Sluckin, Int J Radiat Oncol Biol Phys 2023