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Page 8 of 11 Tirelli et al. J Cancer Metastasis Treat 2023;9:20 https://dx.doi.org/10.20517/2394-4722.2022.98

Table 2. Levels indicated for elective neck dissection according to primary tumor site
Neck levels according to Indication for dissection of
Site of primary cancer [54]
Robbins et al., perimarginal nodes
Oral cavity I-III Yes
Lip I - III Yes
Oropharynx II-IV No
Skin of the head - Area along the course of the facial vein I-III, parotid and facial nodes Yes
Skin of the head - Other subsites - Posterior scalp and Upper II-V, suboccipital and Not enough data/No scientific evidence
neck postauricolar nodes
Skin of the head - Other subsites - Preauricolar, Anterior scalp I-III, parotid and facial nodes Not enough data/No scientific evidence
and Temporal region

undergoing elective ND for cancers of the oral cavity. [Table 2]

The main reason why these lymph nodes are traditionally not routinely excised during elective ND is the
risk of injury to the marginal mandibular nerve . Marginal mandibular nerve injury is a complication that
[13]
causes an aesthetic defect that greatly impacts the patient’s quality of life, often resulting in medicolegal
actions. Many surgical recommendations and techniques have been adopted over the years, but none of
them has been able to totally prevent nerve damage [23,49,50] . The most widespread technique during ND is the
Hayes Martin maneuver which, however, is oncologically unsafe and should be avoided during oncological
surgery [13,51] .

Since PMN metastasis mainly concerns oral cavity tumors, mention should be made of their possible
involvement during the sentinel node biopsy procedure. While not yet universally accepted, sentinel node
biopsy is now incorporated in many national guidelines also for early stage oral cavity SCC . Although
[52]
some papers have reported the presence of positive sentinel nodes at level IIB, it should be noted that the
position of the PMN may hinder the detection of such nodes during the procedure because of the shine-
through phenomenon, particularly if the primary tumor is located in the lower oral cavity (floor of mouth,
tongue, inferior alveolar ridge) . A recent study indeed suggests routinely removing level IB, or at least the
[53]
preglandular triangle, in the floor of mouth tumors even when the sentinel node biopsy is negative, on
account of the increased risk of false negative results due to the shine-through phenomenon .
[52]

CONCLUSIONS
Based on our review of the literature, it is imperative to remove the PMN during ND in all cases of
treatment for oral cavity and lip cancer, regardless of location, tumor stage and neck status. In addition,
their rare involvement in oropharyngeal cancer suggests that removal of the PMN is not mandatory in these
cases and should be avoided due to the risk of injury to the marginal mandibular nerve. Moreover, their
removal should also be considered in facial skin SCC, especially when the tumor originates along the course
of the AFV. Future research on larger series of facial skin SCC will help to further assess the correlation
between the facial region involved by the tumor and metastases to the PMN. Further studies with a long-
term follow-up are needed to verify whether PMN removal could lead to a reduction in locoregional
relapses and an increase in survival.

DECLARATIONS
Acknowledgments
The authors thank Itala Mary Ann Brancaleone, MA, RSA Dip TEFLA, teacher of Medical English at the
University of Trieste, for her support in editing the manuscript.