Table 1.
Baseline demographics and clinical characteristics of the de novo extensive stage small cell lung cancer patients.
| Variable | Overall | Chemotherapy ** | No Chemotherapy *** | p-Value | SMD |
|---|---|---|---|---|---|
| (n = 1465) | (n = 803) | (n = 662) | |||
| Demographics | |||||
| Age, years (mean (SD)) | 69.07 (9.65) | 67.08 (9.15) | 71.50 (9.70) | <0.001 | 0.469 |
| <60 years (%) | 274 (18.8) | 181 (22.5) | 93 (14.0) | <0.001 | 0.221 |
| ≥60 years (%) | 1191 (81.3) | 622 (77.5) | 569 (86.0) | ||
| Male (%) | 741 (50.6) | 414 (51.6) | 327 (49.4) | 0.441 | 0.043 |
| Socioeconomic Status | |||||
| Urban residence (%) | 1138 (77.7) | 634 (79.0) | 504 (76.1) | 0.22 | 0.068 |
| Neighbourhood annual household income in Canadian dollars (mean (SD)) | 36,073.50 (13,518.67) | 36,571.78 (13,359.62) | 35,469.09 (13,694.91) | 0.12 | 0.082 |
| Categories of neighbourhood annual household income in Canadian dollars (%) | 0.051 | 0.146 | |||
| 0–25,000 | 131 (8.9) | 62 (7.7) | 69 (10.4) | ||
| 25,000–35,000 | 703 (48.0) | 372 (46.3) | 331 (50.0) | ||
| 35,000–45,000 | 413 (28.2) | 238 (29.6) | 175 (26.4) | ||
| >45,000 | 218 (14.9) | 131 (16.3) | 87 (13.1) | ||
| Proportion of neighbourhood residents who achieved a high school education or greater (mean (SD)) | 0.74 (0.11) | 0.74 (0.11) | 0.73 (0.11) | 0.09 | 0.089 |
| Categories of neighbourhood education (%) | 0.333 | 0.097 | |||
| 0.00–0.60 | 166 (11.3) | 88 (11.0) | 78 (11.8) | ||
| 0.60–0.70 | 328 (22.4) | 174 (21.7) | 154 (23.3) | ||
| 0.70–0.80 | 510 (34.8) | 272 (33.9) | 238 (36.0) | ||
| >0.80 | 461 (31.5) | 269 (33.5) | 192 (29.0) | ||
| Comorbidity | |||||
| Charlson comorbidity index (%) | <0.001 | 0.306 | |||
| 0 | 601 (41.0) | 369 (46.0) | 232 (35.0) | ||
| 1 | 432 (29.5) | 238 (29.6) | 194 (29.3) | ||
| 2 | 225 (15.4) | 110 (13.7) | 115 (17.4) | ||
| 3 | 105 (7.2) | 52 (6.5) | 53 (8.0) | ||
| ≥4 | 102 (7.0) | 34 (4.2) | 68 (10.3) | ||
| Chronic obstructive pulmonary disease (%) | 532 (36.3) | 265 (33.0) | 267 (40.3) | 0.004 | 0.153 |
| Diabetes (%) | 325 (22.2) | 169 (21.0) | 156 (23.6) | 0.275 | 0.061 |
| Cardiovascular disease (%) | 271 (18.5) | 119 (14.8) | 152 (23.0) | <0.001 | 0.209 |
| Renal disease (%) | 66 (4.5) | 24 (3.0) | 42 (6.3) | 0.003 | 0.16 |
| Liver disease (%) | 56 (3.8) | 26 (3.2) | 30 (4.5) | 0.251 | 0.067 |
| Connective tissue disease (%) | 27 (1.8) | 16 (2.0) | 11 (1.7) | 0.784 | 0.025 |
| Indicators of health | |||||
| Prior cancer | 123 (8.4) | 59 (7.3) | 64 (9.7) | 0.134 | 0.083 |
| No. of hospitalizations within 1 year prior to diagnosis * (%) | <0.001 | 0.326 | |||
| 0 | 1222 (83.4) | 712 (88.7) | 510 (77.0) | ||
| 1 | 153 (10.4) | 64 (8.0) | 89 (13.4) | ||
| 2 | 53 (3.6) | 15 (1.9) | 38 (5.7) | ||
| ≥3 | 37 (2.5) | 12 (1.5) | 25 (3.8) | ||
| No. of ambulatory care encounters within the year prior to diagnosis * (mean (SD)) | 4.27 (9.90) | 3.58 (7.88) | 5.10 (11.84) | 0.004 | 0.15 |
| No. of health practitioner encounters within the year prior to diagnosis * (mean (SD)) | 13.46 (14.73) | 11.89 (10.93) | 15.35 (18.14) | <0.001 | 0.231 |
| Metastatic Sites | |||||
| Number of metastatic sites at diagnosis | 0.269 | 0.133 | |||
| 1 | 548 (37.4) | 285 (35.5) | 263 (39.7) | ||
| 2 | 452 (30.9) | 265 (33.0) | 187 (28.2) | ||
| 3 | 251 (17.1) | 141 (17.6) | 110 (16.6) | ||
| 4 | 126 (8.6) | 70 (8.7) | 56 (8.5) | ||
| ≥5 | 86 (5.9) | 41 (5.1) | 45 (6.8) | ||
| Missing | 2 (0.1) | 1 (0.1) | 1 (0.2) | ||
| Sites of metastasis at diagnosis | |||||
| Hepatic | 695 (47.4) | 363 (45.2) | 332 (50.2) | 0.067 | 0.099 |
| Pleura | 674 (46.0) | 336 (41.8) | 338 (51.1) | 0.001 | 0.186 |
| Osseous | 445 (30.4) | 260 (32.4) | 185 (27.9) | 0.075 | 0.097 |
| Lymph nodes | 282 (19.2) | 171 (21.3) | 111 (16.8) | 0.034 | 0.116 |
| Brain | 266 (18.2) | 148 (18.4) | 118 (17.8) | 0.817 | 0.016 |
| Adrenals | 262 (17.9) | 151 (18.8) | 111 (16.8) | 0.345 | 0.053 |
| Pulmonary | 199 (13.6) | 119 (14.8) | 80 (12.1) | 0.149 | 0.08 |
| Peritoneum | 57 (3.9) | 38 (4.7) | 19 (2.9) | 0.089 | 0.097 |
| Bone marrow | 33 (2.3) | 12 (1.5) | 21 (3.2) | 0.048 | 0.111 |
* Proxy measures for performance status. Abbreviations: SD = standard deviation; SMD = standardized mean difference. ** Includes patients who received chemotherapy alone or in combination with radiotherapy; *** includes patients who received radiotherapy alone or only standard best care.