Table 2 Knowledge on oral cancer, and its risk factors and clinical signs among dental students by the year of study

Demographics

Squamous cell carcinoma is the most common form of oral cancer (N = 904)

No

26 (5.1)

14 (3.5)

40 (4.4)

< 0.001

Yes

414 (81.5)

368 (92.9)

782 (86.5)

I don’t know

68 (13.4)

14 (3.5)

82 (9.1)

The most common site of Squamous cell carcinoma (N = 915)

Tongue and FOM*

275 (53.3)

289 (72.4)

564 (61.6)

< 0.001

Buccal mucosa

149 (28.9)

69 (17.3)

218 (23.8)

Gingiva

45 (8.7)

14 (3.5)

59 (6.4)

Lips

47 (9.1)

27 (6.8)

74 (8.1)

Squamous cell carcinomas mostly diagnosed at advanced stage (N = 857)

No

135 (27.8)

95 (25.6)

230 (26.8)

0.003

Yes

267 (54.9)

239 (64.4)

506 (59)

I don’t know

84 (17.3)

37 (10)

121 (14.1)

Risk factors

Qat chewing (N = 916)

No

164 (31.5)

136 (34.3)

300 (32.8)

0.484

Yes

313 (60.2)

234 (59.1)

547 (59.7)

I don’t know

43 (8.3)

26 (6.6)

69 (7.5)

Smoking (N = 918)

No

34 (6.5)

16 (4)

50 (5.4)

0.188

Yes

438 (92.5)

378 (95.5)

861 (93.8)

I don’t know

5 (1)

2 (0.5)

7 (0.8)

Smokeless tobacco use (N = 916)

No

35 (6.8)

17 (4.3)

52 95.7)

0.115

Yes

468 (90.5)

376 (94.2)

844 (92.1)

I don’t know

4 (2.7)

6 (1.5)

10 (2.2)

Alcohol consumption (N = 915)

No

70 (13.5)

33 (8.3)

103 (11.3)

0.021

Yes

409 (79)

341 (85.9)

750 (82)

I don’t know

39 (7.5)

23 (5.8)

62 (6.8)

Viral factors (N = 911)

No

112 (21.7)

82 (20.8)

194 (21.3)

0.030

Yes

326 (63.1)

274 (69.5)

600 (65.9)

I don’t know

79 (15.3)

38 (9.8)

117 (12.8)

Sun exposure for lip cancer

(N = 911)

No

91 (17.5)

50 (12.8)

141 (15.5)

< 0.001

Yes

370 (71.2)

324 (82.9)

694 (76.2)

I don’t know

59 (11.3)

17 (4.2)

76 (8.3)

Immunosuppression (N = 903)

No

70 (13.7)

49 (12.5)

119 (13.2)

0.811

Yes

387 (75.7)

304 (77.6)

691 (76.5)

I don’t know

54 (10.6)

39 (9.9)

93 (10.3)

Chronic trauma (N = 913)

No

133 (25.7)

43 (10.9)

176 (19.3)

< 0.001

Yes

333 (64.3)

332 (84.1)

665 (72.8)

I don’t know

52 (10)

20 (5.1)

72 (7.9)

Older age (N = 909)

No

219 (42.5)

100 (25.4)

319 (35.1)

< 0.001

Yes

219 (42.5)

260 (63.5)

469 (51.6)

I don’t know

77 (15)

44 (11.2)

121 (13.3)

Low consumption of fruits and vegetables (N = 900)

No

272 (53.4)

191 (48.8)

463 (51.4)

0.031

Yes

139 (27.3)

138 (35.3)

277 (30.8)

I don’t know

98 (19.3)

52 (15.9)

160 (17.8)

Family history of cancer (N = 914)

No

122 (23.5)

91 (23.1)

213 (23.3)

0.146

Yes

358 (68.8)

285 (72.2)

643 (70.4)

I don’t know

40 (7.7)

18 (4.6)

58 (6.3)

Poor oral hygiene (N = 906)

No

156 (30.4)

127 (32.3)

283 (31.2)

0.598

Yes

309 (60.2)

236 (60.1)

545 (60.2)

I don’t know

48 (9.4)

30 (7.6)

78 (8.6)

Poorly fitting denture (N = 916)

No

155 (29.8)

72 (18.2)

227 (24.8)

< 0.001

Yes

291 (55.9)

296 (74.9)

587 (64.1)

I don’t know

75 (14.4)

27 (6.8)

102 (11.1)

Clinical signs

Non-healing ulcer (N = 914)

No

50 (9.6)

25 (6.3)

75 (8.2)

< 0.001

Yes

413 (79.4)

356 (90.4)

769 (84.1)

I don’t know

57 (11)

13 (3.3)

70 (7.7)

Red lesion (N = 903)

No

114 (22.3)

86 (22)

200 (22.1)

0.074

Yes

320 (62.5)

265 (67.8)

585 (64.8)

I don’t know

78 (15.2)

40 (10.2)

118 (13.1)

White lesion (N = 902)

No

95 (18.7)

70 (17.8)

165 (18.3)

< 0.001

Yes

327 (64.2)

294 (74.8)

621 (68.8)

I don’t know

87 (17.1)

29 (7.4)

116 (12.9)

Speckled (red and white) lesion (N = 897)

No

61 (12)

29 (7.5)

90 (10)

< 0.001

Yes

358 (70.5)

324 (83.3)

682 (76)

I don’t know

89 (17.5)

36 (9.3)

125 (13.9)

Lump (N = 906)

No

48 (9.4)

50 (12.7)

98 (10.8)

0.110

Yes

420 (81.9)

319 (81.2)

739 (81.6)

I don’t know

45 (8.8)

24 (6.1)

69 (7.6)

Bleeding (N = 907)

No

191 (37.1)

133 (33.9)

324 (35.7)

0.007

Yes

212 (41.2)

199 (50.8)

411 (45.3)

I don’t know

112 (21.7)

60 (15.3)

172 (19)