Table 2.
Comparison of baseline characteristics between surgery and radiotherapy for second primary lung cancer before and after propensity score matching (PSM).
| Characteristic | Before PSM | After PSM | |||||||||||||||||||
|
|
Radiation (n=864) | Surgery (n=759) | P value | Radiation (n=470) | Surgery (n=470) | P value | |||||||||||||||
| Age (years), mean (SD) | 63.9 (8.9) | 62.1 (9.0) | <.001 | 63.0 (8.8) | 62.7 (9.1) | .55 | |||||||||||||||
| Race, n (%) | .10 |
|
.75 | ||||||||||||||||||
|
|
White | 737 (85.3) | 642 (84.6) |
|
401 (85.3) | 393 (83.6) |
|
||||||||||||||
|
|
Black | 85 (9.8) | 63 (8.3) |
|
39 (8.3) | 45 (9.6) |
|
||||||||||||||
|
|
Other | 42 (4.9) | 54 (7.1) |
|
30 (6.4) | 32 (6.8) |
|
||||||||||||||
| Sex, n (%) | .005 |
|
.95 | ||||||||||||||||||
|
|
Male | 417 (48.3) | 313 (41.2) |
|
201 (42.8) | 203 (43.2) |
|
||||||||||||||
|
|
Female | 447 (51.7) | 446 (58.8) |
|
269 (57.2) | 267 (56.8) |
|
||||||||||||||
| Relative location, n (%) | <.001 |
|
.73 | ||||||||||||||||||
|
|
Ipsilateral | 321 (37.2) | 208 (27.4) |
|
152 (32.3) | 146 (31.1) |
|
||||||||||||||
|
|
Contralateral | 543 (62.8) | 551 (72.6) |
|
318 (67.7) | 324 (68.9) |
|
||||||||||||||
| Diagnostic interval (months), mean (SD) | 104.4 (48.7) | 95.8 (45.3) | <.001 | 99.1 (43.5) | 100.9 (50.5) | .56 | |||||||||||||||
| IPLCa | |||||||||||||||||||||
|
|
Year of diagnosis | .004 |
|
.93 | |||||||||||||||||
|
|
|
1988-1995 | 242 (28) | 256 (33.7) |
|
135 (28.7) | 135 (28.7) |
|
|||||||||||||
|
|
|
1996-2003 | 313 (36.2) | 286 (37.7) |
|
174 (37) | 169 (36) |
|
|||||||||||||
|
|
|
2004-2012 | 309 (35.8) | 217 (28.6) |
|
161 (34.3) | 166 (35.3) |
|
|||||||||||||
|
|
SEERb stage | .499 |
|
.73 | |||||||||||||||||
|
|
|
Localized | 560 (64.8) | 505 (66.5) |
|
300 (63.8) | 306 (65.1) |
|
|||||||||||||
|
|
|
Regional | 304 (35.2) | 254 (33.5) |
|
170 (36.2) | 164 (34.9) |
|
|||||||||||||
|
|
Histology | <.001 |
|
.82 | |||||||||||||||||
|
|
|
ADCc | 451 (52.2) | 495 (65.2) |
|
275 (58.5) | 275 (58.5) |
|
|||||||||||||
|
|
|
SCCd | 280 (32.4) | 173 (22.8) |
|
125 (26.6) | 131 (27.9) |
|
|||||||||||||
|
|
|
Other NSCLCe | 133 (15.4) | 91 (12) |
|
70 (14.9) | 64 (13.6) |
|
|||||||||||||
|
|
Grade | .06 |
|
≥.99 | |||||||||||||||||
|
|
|
Well differentiated | 82 (9.5) | 106 (14) |
|
50 (10.6) | 52 (11.1) |
|
|||||||||||||
|
|
|
Moderately differentiated | 295 (34.1) | 259 (34.1) |
|
167 (35.5) | 168 (35.7) |
|
|||||||||||||
|
|
|
Poorly differentiated | 295 (34.1) | 231 (30.4) |
|
149 (31.7) | 148 (31.5) |
|
|||||||||||||
|
|
|
Undifferentiated | 42 (4.9) | 33 (4.3) |
|
22 (4.7) | 23 (4.9) |
|
|||||||||||||
|
|
|
Unknown | 150 (17.4) | 130 (17.1) |
|
82 (17.4) | 79 (16.8) |
|
|||||||||||||
|
|
Surgery | <.001 |
|
.98 | |||||||||||||||||
|
|
|
No surgery | 102 (11.8) | 47 (6.2) |
|
45 (9.6) | 42 (8.9) |
|
|||||||||||||
|
|
|
Sublevel resection | 100 (11.6) | 105 (13.8) |
|
59 (12.6) | 61 (13) |
|
|||||||||||||
|
|
|
Lobectomy | 616 (71.3) | 591 (77.9) |
|
353 (75.1) | 355 (75.5) |
|
|||||||||||||
|
|
|
Pneumonectomy | 46 (5.3) | 16 (2.1) |
|
13 (2.8) | 12 (2.6) |
|
|||||||||||||
|
|
Chemotherapy | .77 |
|
.87 | |||||||||||||||||
|
|
|
Yes | 155 (17.9) | 131 (17.3) |
|
91 (19.4) | 88 (18.7) |
|
|||||||||||||
|
|
|
No/unknown | 709 (82.1) | 628 (82.7) |
|
379 (80.6) | 382 (81.3) |
|
|||||||||||||
|
|
Radiotherapy | .04 |
|
.93 | |||||||||||||||||
|
|
|
Yes | 176 (20.4) | 123 (16.2) |
|
86 (18.3) | 88 (18.7) |
|
|||||||||||||
|
|
|
No/unknown | 688 (79.6) | 636 (83.8) |
|
384 (81.7) | 382 (81.3) |
|
|||||||||||||
| SPLCf | |||||||||||||||||||||
|
|
Chemotherapy | <.001 |
|
≥.99 | |||||||||||||||||
|
|
|
Yes | 318 (36.8) | 91 (12) |
|
88 (18.7) | 87 (18.5) |
|
|||||||||||||
|
|
|
No/unknown | 546 (63.2) | 668 (88) |
|
382 (81.3) | 383 (81.5) |
|
|||||||||||||
aIPLC: initial primary lung cancer.
bSEER: Surveillance, Epidemiology, and End Results.
cADC: adenocarcinoma.
dSCC: squamous cell carcinoma.
eNSCLC: non-small cell lung cancer.
fSPLC: second primary lung cancer.