Table 1. Basic characteristics of the 17 studies used in our meta-analysis.
| Studies | Study design | Country | No. of patients (CT/RT/RCT) | Sex (male) | Median age | Stage (IE/IIE) | ECOG score (≤1/≥2) | B symptoms | High LDH | Primary site |
| HH Ma [23] | retrospective | China | 0/23/41 | 36 | 44 | 51/13 | 62/2 | 34 | 9 | 44 patients: nasal cavity, paranasal sinus |
| GE Kim [24] | retrospective | Korea | 0/104/39 | 68 | 46 | 70/34 | NR | 18 | NR | nasal cavity/paranasal sinuses, larynx/hypopharynx, Waldeyer's ring, oral cavity/soft palate |
| K Kim [25] | retrospective | Korea | 0/33/20 | 37 | 45 | 42/11 | 44/9 | 11 | NR | nasal cavity, paranasal sinuses, nasopharynx, oropharynx, hypopharynx, oral cavity |
| A. Avilé s [28] | prospective | Mexico | 116/109/202 | 201 | NR | 247/179 | NR | 3 | 40 | nasal cavity, nasopharynx, paranasal sinuses, tonsils, hypopharynx, hard palate |
| SY Li [29] | retrospective | America | 2/7/30 | NR | NR | NR | NR | NR | NR | NR |
| JL Luo [30] | retrospective | China | 2/30/98 | 91 | NR | 116/14 | 129/1 | 33 | NR | NR |
| A Chauchet [31] | multicenter retrospective | France | 8/0/8 | NR | NR | 10/6 | NR | NR | NR | NR |
| YX Li [32] | retrospective | China | 0/96/118 | 141 | 42 | 182/32 | 198/16 | 67 | 73 | nasal cavity |
| YX Li [33] | retrospective | China | 4/13/54 | NR | NR | 15/56 | NR | NR | NR | nasopharynx, tonsil |
| MJ Huang [34] | retrospective | China | 8/9/65 | 57 | 45 | 52/30 | 66/16 | 43 | 31 | nasal cavity, paranasal sinuses, other parts of the upper aerodigestive tract, other sites outside nasal cavity of the upper aerodigestive tract |
| SJ Kim [35] | retrospective | Korea | 26/0/17 | 30 | 40 | 24/19 | 37/6 | NR | 12 | nasal cavity, nasopharynx, tonsil, oropharynx, hypopharynx, palate |
| K Isobe [36] | prospective | Japan | 0/17/18 | 21 | 51 | 32/3 | NR | 7 | 7 | nasal cavity, paranasal sinuses, pharynx |
| IWK Tham [37] | retrospective | Singapore | 0/5/13 | NR | NR | 13/5 | NR | NR | NR | nasal, Waldeyer's ring, both |
| CC Li [38] | retrospective | Taiwan | 18/11/27 | 42 | 45 | NR | NR | NR | NR | nasal area, paranasal sinuses, nasopharynx, oropharynx, pharynx, tonsils |
| MM Cheung [39] | retrospective | Hong Kong | 0/18/61 | 58 | 53 | 63/16 | 72/7 | 22 | 20 | nasal cavity, nasopharynx |
| V Ribrag [40] | retrospective | France | 12/6/2 | 14 | 44 | 16/4 | NR | NR | NR | nasal cavity, oropharynx, palate |
| YX Li [41] | retrospective | China | 3/31/71 | 69 | 42 | 83/22 | 87/18 | 37 | 53 | left, right, bilateral nasal cavity |
CT: chemotherapy; RT: radiotherapy; RCT: radiochemotherapy; ECOG: Eastern Cooperative Oncology group; LDH: lactic dehydrogenase; NR: not reported; No.: number.