High Lymph Node Yield is Related to Microsatellite Instability in Colon Cancer

Abstract

BackgroundLymph node (LN) yield in colon cancer resection specimens is an important indicator of treatment quality and has especially in early-stage patients therapeutic implications. However, underlying disease mechanisms, such as microsatellite instability (MSI), may also influence LN yield, as MSI tumors are known to exhibit more prominent lymphocytic antitumor reactions. The aim of the present study was to investigate the association of LN yield, MSI status, and recurrence rate in colon cancer.MethodsClinicopathological data and tumor samples were collected from 332 stage II and III colon cancer patients. DNA was isolated and PCR-based MSI analysis performed. LN yield was defined as “high” when 10 or more LNs were retrieved and “low” in case of fewer than 10 LNs.ResultsTumors with high LN yield were significantly associated with the MSI phenotype (high LN yield: 26.3% MSI tumors vs low LN yield: 15.1% MSI tumors; P = .01), mainly in stage III disease. Stage II patients with high LN yield had a lower recurrence rate compared with those with low LN yield. Patients with MSI tumors tended to develop fewer recurrences compared with those with MSS tumors, mainly in stage II disease.ConclusionsIn the present study, high LN yield was associated with MSI tumors, mainly in stage III patients. Besides adequate surgery and pathology, high LN yield is possibly a feature caused by biologic behavior of MSI tumors.

Influence of Microsatellite Instability and KRAS and BRAF Mutations on Lymph Node Harvest in Stage I–III Colon Cancers

“…The current results substantiate previous findings by our group (11) and others (12,13) demonstrating an effect of MSI in determining the actual LN counts after surgery. Both MSI and proximal tumor location appear to be associated with a higher LN harvest, both independently and in combination.…”

“…However, in a previous cohort, we found that microsatellite instability (MSI) was associated with the total number of LNs harvested (11), which has been confirmed by others (12,13). The aim of the present study was to further investigate MSI and KRAS and BRAF mutations and their relationship to the number of harvested LNs in colon cancer patients.…”

“…Both MSI and proximal tumor location appear to be associated with a higher LN harvest, both independently and in combination. This relationship has been demonstrated in different populations with the use of various cutoffs to determine the appropriate nodal count (11)(12)(13)23). In contrast to these studies, a Canadian study found no significant difference between the effects of MSI and MSS on LN harvest in 168 selected stage III colon cancer patients (27).…”

“…The median number of harvested nodes was 14 (range 4-43; interquartile range [11][12][13][14][15][16][17][18][19], with significantly more nodes found in women, in proximal located tumors, in MSI genotype and larger (≥5 cm) tumors ( Table 1). The total nodes sampled for each frequency stratum of MSI is presented in Figures 1A-C, with and without tumor location.…”

Lymph Node Evaluation for Colon Cancer in Routine Clinical Practice: A Population-Based Study

“…Galon et al 41 coined the term "immune contexture" to describe the effect of the local host immune reaction in crc. There is a negative association between senescence and decreased nodal count 27 , and possibly a stronger association between comorbidity and diminished immunity 28 ; also, patients with crcs that genomically harbour microsatellite instability have a propensity for right-sided malignancies 42 , higher ln yields 43 , and better overall prognosis 44 . Given those findings, it is entirely plausible that ln yield is the surrogate marker for an immune response that reflects inherent prognosis.…”