Page 55 - Read Online

Tirelli et al. J Cancer Metastasis Treat 2023;9:20 https://dx.doi.org/10.20517/2394-4722.2022.98 Page 3 of 11

but adding a sixth group of submandibular nodes, called deep submandibular nodes. These lymph nodes,
when present, are small and are found on the deep surface of the submandibular gland. They are superficial
[14]
to the mylohyoid muscle or posterior to the hyoglossal muscle . This classification has been used in the
recent surgical oncology literature, such as the study by Dhiwakar et al. which attempted to determine
whether all lymph nodes in sublevel IB could be oncologically safely extirpated without removing the
[15]
submandibular gland . [Figure 1]
PERIFACIAL NODES
The retrovascular and prevascular lymph nodes are also defined by some authors as perifacial nodes (PFN),
because of their relation to the AVF. Despite the similar name, these nodes do not belong to the facial node
group. Facial nodes were classified by Rouvière into four groups: inferior maxillary, buccinator, infraorbital
(nasolabial), and malar . They lie above the inferior limit of the mandible, whereas the PFN, being below
[10]
[13]
this limit, must be considered part of level IB . According to the literature, the PFN drain from the oral
mucosa, oropharyngeal mucosa and the skin and subcutaneous tissue of the face [2,16] . Few studies have
investigated the role of the PFN in head and neck cancer, and some of them consider the PFN as a different
group of lymph nodes. Creighton et al. tried to determine the frequency of nodal metastases from skin
malignancy (melanoma 63.5%, squamous cell carcinoma 20.1%) of the head and neck in non-traditional
lymph node stations. In his study, the PFN are considered a non-traditional nodal group and were
distinguished from levels of the neck . The primary tumors were located in the scalp, forehead, cheek, ear,
[17]
nose, periocular area and lip, and PFN metastases were present in 10/145 (6.9%) of cases, especially when
the primary tumor was located in the nose (3/7; 42.9%) and lip (2/6; 33.3%), but also in the forehead, scalp
and cheek. The study concluded that dissection of the PFN should be performed in all elective and
completion lymphadenectomies for primary malignancies of the nose and lips . In a study aiming to
[17]
identify factors associated with recurrence of squamous cell carcinoma (SCC) involving the temporal bone,
McRackan et al. described the PFN as a different group and concluded that, as compared to cervical lymph
node involvement, involvement of the PFN was not associated with an increased risk of recurrence .
[18]
Additionally, Scurry et al. considered the PFN to be a different node group. In their systematic review
assessing whether the regional recurrence of nasal cavity SCC was higher than previously suspected, they
reported a rate of 18.1% and recommended that patients with intranasal SCC and additional high-risk
characteristics should be treated with ND or radiotherapy, suggesting that the PFN region should be treated
with radiotherapy because of the difficulty and potential morbidity of surgical dissection in that area . In a
[19]
retrospective study, Lim et al. investigated the incidence of metastases to the PFN . They considered the
[2]
PFN as nodal pads that lie anterior or posterior to the AFV on top of the facial artery in the submandibular
gland triangle. Patients with oral or oropharyngeal SCC and with clinically node-positive necks were
included. The incidence of PFN metastases was 10 (15%) cases. In 35% of them, the primary lesion was in
the oral cavity, while in 8%, it was located in the oropharynx. Seven of 63 (11%) cases, which had no
clinically positive lymph nodes in level I, had PFN metastases, of which 4/15 (27%) were from an oral cavity
[2]
primary cancer and 3/48 (6%) were from an oropharyngeal primary .
In another study, Lim et al. analyzed the incidence of occult metastasis in the PFN and nodal recurrence in
[16]
these nodal pads in SCC of the tongue and floor of mouth . They found that 4/72 (5.5%) patients with
tongue cancer and 2/27 (7.4%) patients with the floor of mouth cancer had a positive metastatic PFN node,
with an incidence of regional recurrence at level I of 3 in 45 (6.7%) . Agarwal et al. studied the incidence of
[16]
[20]
isolated PFN metastasis in 231 oral SCC patients who had a clinically negative neck . The primary tumor
was located in the buccal mucosa in 116/231 (50.2%) and in the oral tongue in 84/231 (36.36%). Nineteen of
231 (8.22%) patients had ipsilateral isolated PFN metastasis, but the incidence did not differ between oral
tongue (6/84; 7.1%) and buccal mucosa (9/116; 7.7%). In his series, the incidence of isolated PFN was
statistically significant in patients with cancers stage T3 and T4 .
[20]