Introduction
Cutaneous squamous cell carcinoma (CSCC) is the second-most common
neoplasia in humans after basal cell carcinoma; about 1.2 million new
cases of head and neck skin cancer are estimated in 2040, with 680,000
deaths.1 In Brazil, 173,930 new cases of non-melanoma
skin cancer are estimated in 2020, with about 2,000 deaths2. Approximately 80% of CSCCs are located in the head
and neck region and advanced CSCC have a mortality rate of 20%,
although this value may have been underestimated due to the lack of
precise data in developing countries in South and Central America.
Advanced CSCC is defined as locally invasive in deep anatomic structures
with or without presence of regional or distant metastasis; nominated
as locally advanced (laCSCC) and metastatic (mCSCC); classified as
T3/T4, stage III or IV, where no parotid and locally treatment standards
are stablished; the relapsed CSCC (reCSCC) is defined as multiple
recurrences after successfully margins free resection6. The estimated incidence was 8.000 cases of nodal
metastasis and 3.000 deaths annually for both laCSCC and mCSCC whose
still are in a standardized area of unmet medical need7.
The recommendations of treatment are based on literature review and
guidelines, generally, primary surgical excision with safety margins and
the appropriate lymph nodes chain dissection are necessary on the proven
positive regional metastasis or in the high risk patient, but still,
debate exists in the clinically negative neck and the extension of the
parotidectomy 8 .
The incidence of parotid metastasis from CSCC is not common, occurring
in 1% to 5% of all cases of CSCC in the head and neck region and
regional metastasis can occur up to five years after resection of the
primary 3-5. The high-risk clinical features for
parotid and neck metastasis from CSCC include size (T); depth; scalp,
ear pavilion; immunosuppression; recurrence; poor differentiation and
others 9-12. Recently the immunosuppression induced by
drug delivery to organ transplants patients, to those with autoimmune
diseases and other clinical comorbidities (diabetes mellitus), has been
recognized as an important risk factor for the development of CSCC, with
growing incidence and mortality in the world 13,14.
Parotid metastasis from CSCC has an unfavorable prognosis, with lower
survival, higher incidence of locoregional recurrence, high
extracapsular spread and occult neck metastasis; however, there are few
information about the biological tumoral spread from parotid to neck
nodes 5,11,15-17. There are some parotid and neck
staging systems, denominating it as positive (P+) or negative (P0); or
the N1S3 classification, which does not have consensus worldwide. At
present, the most accepted system is the TNM system, although the pN
staging evaluation is directly affected by surgical technique,
dissection amount, and the quality of pathologic examination18-22.
To the present, no consensus exists regarding the parotid treatment and
the indication and extent of neck dissection in the reCSCC and laCSCC;
the identification of the risk factors for parotid metastasis in reCSCC
and la CSCC can allow selecting the proper treatment approach for the
parotid gland and to the neck dissection.