Table 1.
Summarizes the main characteristics of reviewed studies. Table S2 (in Supplementary Materials, pp. 4, 5) exhibits in detail the characteristics of each study. *—More than one biomarker and type of tumor were analyzed per study.
| Total | 16 Studies |
|---|---|
| Year of publication | 1983–2020 |
| Number of cases | |
| Total | 909 |
| Sample size, range | 5–114 |
| Biomarkers analyzed * | |
| SP | 15 studies (897 cases) |
| NK-1R | 7 studies (411 cases) |
| Affected sites | |
| Oral cavity | 4 studies (285 cases) |
| Nasal cavity | 1 study (20 cases) |
| Larynx | 2 studies (233 cases) |
| Salivary glands | 1 study (171 cases) |
| Thyroid gland | 6 studies (142 cases) |
| Head and neck mixed | 2 studies (58 cases) |
| Type of tumors * | |
| Benign | 5 studies (226 cases) |
| Pre-malignant | 3 studies (230 cases) |
| Malignant | 11 studies (453 cases) |
| Study design | |
| Retrospective cohort | 16 studies |
| Geographical region | |
| Europe | 11 studies (610 patients) |
| Asia | 3 studies (216 cases) |
| North-Central America | 2 studies (83 cases) |