HEALTH PROFESSIONAL · SOURCE READING

Regional Lymph Node Surgery

Source: Merkel Cell Carcinoma Treatment (PDQ®)–Health Professional Version, National Cancer Institute.

Source updated: May 9, 2025 · Captured 2026-09-09.

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Context: Treatment Option Overview for Merkel Cell Carcinoma

In some case series, local-regional recurrence rates are high when pathological nodal staging is omitted. Surgical nodal staging in clinically negative patients has identified positive nodes in at least 25% to 35% of patients.[4,11,12][Level of evidence C2] In one retrospective series of 213 patients who underwent surgical treatment of the primary tumor and evaluation of the draining nodes, nodal positivity was found in 2 of 54 patients with small tumors (e.g., ≤1.0 cm) and 51 of 159 patients with tumors larger than 1.0 cm.[13][Level of evidence C2]

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The role of elective lymph node dissection (ELND) in the absence of clinically positive lymph nodes has not been studied in formal clinical trials. In small case series, ELND has been recommended for larger primary tumors, tumors with more than ten mitoses per high-power field, lymphatic or vascular invasion, and the small-cell histological subtypes.[14-16][Level of evidence C2]

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Sentinel lymph node (SLN) biopsy has been suggested as a preferred initial alternative to complete ELND for the proper staging of MCC. SLN biopsy has less morbidity than complete nodal dissection. Furthermore, for MCC sites with indeterminate lymphatic drainage, such as those on the back, SLN biopsy techniques can be used to identify the pertinent lymph node bed(s). If performed, SLN biopsy is done at the time of the wide resection when the local lymphatic channels are still intact.

Several reports have found the use of SLN biopsy techniques in MCC to be reliable and reproducible.[17-20] However, the significance of SLN positivity remains unclear.

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One meta-analysis of ten case series found that SLN positivity strongly predicted a high short-term risk of recurrence and that subsequent therapeutic lymph node dissection was effective in preventing short-term regional nodal recurrence.[21]

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Another meta-analysis included 12 retrospective case series (only partially overlapping the collection of case series in the previous meta-analysis).[12][Level of evidence C2]

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Another meta-analysis included 12 retrospective case series (only partially overlapping the collection of case series in the previous meta-analysis).[12][Level of evidence C2]

SLN biopsy detected MCC spread in one-third of patients whose tumors would have otherwise been clinically and radiologically understaged.

Another meta-analysis included 12 retrospective case series (only partially overlapping the collection of case series in the previous meta-analysis).[12][Level of evidence C2]

The recurrence rate was three times higher in patients with a positive SLN biopsy than in those with a negative SLN biopsy (P = .03).

Between 2006 and 2010, a large, retrospective, single-institutional series of 95 patients (with a total of 97 primary tumors) identified a SLN in 93 instances, and nodal tumor was seen in 42 patients. Immunohistochemical techniques were used to assess node positivity. Various models of tumor and patient characteristics were studied to predict node positivity. There was no subgroup of patients predicted to have lower than 15% to 20% likelihood of SLN positivity, suggesting that SLN biopsy may be considered for all curative patients with clinically negative lymph nodes and no distant metastases.[22][Level of evidence C2]

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From 1996 to 2010, another retrospective single-institutional study of 153 patients with localized MCC who underwent SLN biopsy analyzed factors associated with SLN positivity. The best predictors of SLN biopsy positivity were tumor size and lymphovascular invasion.[22,23][Level of evidence C2]

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In the absence of adequately powered, prospective, randomized clinical trials, the following questions remain:[4,12,21,24][Level of evidence C2]

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Should every positive SLN biopsy be followed routinely by completion nodal surgery and/or radiation therapy?

Are outcomes demonstrably improved by routinely adding radiation if lymph node surgery reveals tumor in multiple nodes and/or extracapsular extension and/or lymphovascular invasion?

Should patients with MCCs smaller than 1 cm routinely undergo sentinel lymph node dissection (SLND)?

Should patients with negative or omitted nodal work-up routinely undergo local or local-regional radiation therapy?

Should immunohistochemical staining techniques be used to identify micrometastases in lymph nodes, and is micrometastatic disease in nodes clinically relevant?

Lymph node surgery is primarily used for staging and guiding additional treatment.

Based on a small number of retrospective studies, therapeutic dissection of the regional lymph nodes after a positive SLND appears to minimize, but not totally eliminate, the risk of subsequent regional lymph node recurrence and in-transit metastases.[4,21,24][Level of evidence C2] There are no data from prospective randomized trials demonstrating that definitive regional nodal treatment with surgery improves survival.

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Preserved source evidence · Not medical advice