Work

Locally Recurrent Rectal Cancer in the Lateral Compartment: Imaging Features and Association with Primary Tumour Characteristics

Year: 2026

Type: article

Abstract: BACKGROUND AND PURPOSE: Locally recurrent rectal cancer (LRRC) involving the lateral pelvic compartment is associated with a poor prognosis. The underlying aetiology, such as lateral lymph node(s) (LLN) metastases or other high-risk features, remains unclear. This study aimed to investigate features of lateral LRRC and their anatomical association with primary tumour characteristics. METHODS: All patients with lateral LRRC referred to our centre between 2018 and 2025 were included (n = 104). Primary and recurrent tumour MRIs were centrally re-reviewed to evaluate tumour features. An expert panel further assessed anatomical relationships between the primary tumour locations and lateral LRRC sites. Primary outcome was to characterise recurrence features; secondary outcomes were overall and local re-recurrence-free survival. RESULTS: Primary tumours of 104 patients frequently showed a high prevalence of high-risk radiological features: extramural vascular invasion (45%), cT3cd-cT4ab staging (47%), tumour deposits (23%) and pathological LLNs (≥ 7 mm short axis, LLN+, 20%). In patients with LLN+ primary tumours (n = 21), the incidence of the other synchronous high-risk features was significantly increased. Within this group, primary LLN dissection (LLND) was performed in 7/21 (33%). Subsequent lateral LRRC due to LLN nodal recurrence occurred in 10/21 (48%), including 4 patients who had undergone LLND. Overall, the expert panel linked 11% of lateral LRRC to LLNs visible on primary imaging, and the remaining 89% to other causes. CONCLUSIONS: Only a minority of lateral LRRCs could be attributed to primary LLN+. Other causes, related to primary tumour spread and high-risk features, appear to be associated with the majority of lateral LRRC, suggesting a multifactorial aetiology.

Source: Annals of Surgical Oncology

DOI: 10.1245/s10434-025-19068-w