| S. No. | First Author | Total No. of Subjects | EGFR-positive Subjects | ||||
| Smokers, n (%) | Non-smokers, n (%) | Others (Reformed, Former, Unknown) | Smokers, n (%) | Non-smokers, n (%) | Others (Reformed, Former, Unknown,) | ||
| 1 | Samdariya et al. [49] | 81 (61) | 52 (39) | NA | NA | NA | NA |
| 2 | Rana et al. [50] | NA | NA | NA | NA | NA | NA |
| 3 | Bal et al. [28] | NA | NA | NA | NA | NA | NA |
| 4 | Verma et al. [21] | 56 (81.2) | 13 (18.8) | NA | NA | NA | NA |
| 5 | Doval et al. [30] | 164 (32.8) | 250 (50) | Unknown 86 (17.2) | 29 (17.7) | 108 (43.2) | 27 (31.4) |
| 6 | Doval et al. [51] | 167 (51.9) | 138 (42.9) | NA | NA | NA | NA |
| 7 | Bhatt et al. [52] | 35 (33.0) | 71 (67) | NA | 7 (16.7) | 35 (83.3) | NA |
| 8 | Shankar et al. [53] | NA | NA | NA | NA | NA | NA |
| 9 | Singh et al. [20] | NA | NA | NA | NA | NA | NA |
| 10 | Ashutosh et al. [36] | 32 (31) | 40 (39) | Reformed 31 (30) | NA | NA | NA |
| 11 | Sahoo et al. [54] | 104 (47) | 116 (53) | NA | 64 (56.1) | 50 (43.9) | NA |
| 12 | Bala et al. [29] | 177 (50.1) | 176 (49.9) | NA | NA | NA | NA |
| 13 | Jain et al. [25] | 12* (48) | 13* (52) | NA | NA | NA | NA |
| 14 | Sharma et al. [19] | 24 (50) | 21 (44) | NA | 4 (21.1) | 15 (78.9) | NA |
| 15 | Udupa et al. [35] | 39 (46) | 46 (54) | NA | NA | NA | NA |
| 16 | Chatterjee et al. [17] | NA | NA | NA | NA | NA | NA |
| 17 | Vaid et al. [27] | 37 (46) | 43 (54) | NA | 9 (41) | 13 (59) | NA |
| 18 | Chatterjee et al. [16] | 28 (26.4) | 78 (73.6) | NA | 5 (14.3) | 30 (85.7) | NA |
| 19 | Ansari et al. [55] | 23 (38) | 38 (62) | NA | NA | NA | NA |
| 20 | Kota et al. [56] | 41 (37) | 70 (63) | NA | 5 (14.7) | 29 (85.3) | NA |
| 21 | Singh et al. [34] | 86 (68.8) | 39 (31.2) | NA | 19 (61.2) | 12 (38.7) | NA |
| 22 | Gupta et al. [57] | NA | NA | NA | NA | NA | NA |
| 23 | Noronha et al. [33] | 231 (39.9) | 349 (60.1) | NA | 59 (26) | 168 (74) | NA |
| 24 | Kasana et al. [32] | 32 (56.1) | 25 (43.9) | NA | 7 (35) | 13 (65) | NA |
| 25 | Choughule et al. [18] | 382 (37.5) | 597 (58.6) | Unknown 6 (15) | 61 (25) | 188 (77) | NA |
| 26 | Bharadwaj et al. [58] | 48 (80) | 12 (20) | Former 7 (11.7) | 7 (38.9) | 8 (44.4) | 3 (16.6) |
| 27 | Poonamalle et al. [23] | 21 (60) | 14 (40) | NA | NA | NA | NA |
| 28 | Dutt et al. [24] | NA | NA | NA | NA | NA | NA |
| 29 | Prabhash et al. [42] | 88 (35) | 147 (58) | Former Smoker 69 (29.4) | 5 (9.3) | 45 (83.3) | 4 (7.4) |
| 30 | Doval et al. [31] | 71 (43) | 95 (57) | Former Smoker 28 (16.9) | 4 (9.3) | 6 (21.4) | 33 (34.7) |
| 31 | Dang et al. [59] | NA | NA | NA | NA | NA | NA |
| 32 | Chougule et al. [41] | 360 (39.6) | 516 (56.8) | Unknown 31 (3.4) | 55 (26.2) | 152 (72.4) | 3 (1.4) |
| 33 | Noronha et al. [26] | 23 (21) | 88 (79.2) | NA | 4 (10.3) | 35 (89.7) | NA |
| 34 | Kumari et al. [60] | 115 (46) | 135 (54) | NA | 29 (36.8) | 50 (63) | NA |