Table 1.
The baseline characteristics.
| Characteristics | Training cohort No. (%) | Validation cohort No. (%) | P -value |
|---|---|---|---|
| Total | 5,094 (75) | 1,698 (25) | |
| Year of diagnosis | 0.638 | ||
| 2004–2009 | 2,084 (40.5) | 659 (39.9) | |
| 2010–2016 | 3,056 (59.5) | 993 (60.1) | |
| Primary site | 0.346 | ||
| Labium majus | 423 (8.2) | 125 (7.6) | |
| Labium minus | 238 (4.6) | 68 (4.1) | |
| Clitoris | 100 (1.9) | 23 (1.4) | |
| Overlapping lesion of vulva | 228 (4.4) | 68 (4.1) | |
| Vulva, NOS | 4,151 (80.8) | 1,368 (82.8) | |
| Age | 0.859 | ||
| Median (IQR) | 66 (53–79) | 65 (53–79) | |
| 18–39 | 258 (5.0) | 85 (5.1) | |
| 40–59 | 1,694 (33.0) | 528 (32.0) | |
| 60–79 | 1,949 (37.9) | 643 (38.9) | |
| ≥80 | 1,239 (24.1) | 396 (24.0) | |
| Insurance | 0.594 | ||
| Insured | 3,124 (60.8) | 1,011 (61.2) | |
| Medicaid | 675 (13.1) | 225 (13.6) | |
| Uninsured | 159 (3.1) | 41 (2.5) | |
| Unknown | 1,182 (23.0) | 375 (22.7) | |
| Marital status | 0.81 | ||
| Married | 1,856 (36.1) | 598 (36.2) | |
| Single | 932 (18.1) | 297 (18.0) | |
| Divorced/separated/windowed | 1,953 (38.0) | 640 (38.7) | |
| Unknown | 399 (7.8) | 117 (7.1) | |
| Tumor size | 0.999 | ||
| <2 cm | 1,464 (28.5) | 471 (28.5) | |
| 2–4 cm | 1,239 (24.1) | 399 (24.2) | |
| ≥4 cm | 1,375 (26.8) | 443 (26.8) | |
| Unknown | 1,062 (20.7) | 339 (20.5) | |
| Pathological grade | 0.176 | ||
| Grade I | 1,344 (26.1) | 401 (24.3) | |
| Grade II | 1,976 (38.4) | 627 (38.0) | |
| Grade III/IV | 836 (16.3) | 271 (16.4) | |
| Unknown | 984 (19.1) | 353 (21.4) | |
| Historic stage | 0.386 | ||
| Localized | 2,808 (54.6) | 923 (55.9) | |
| Regional | 1,879 (36.6) | 569 (34.4) | |
| Distant | 286 (5.6) | 99 (6.0) | |
| Unstaged | 167 (3.2) | 61 (3.7) | |
| Radiotherapy | 0.147 | ||
| No | 3,521 (68.5) | 1,163 (70.4) | |
| Yes | 1,619 (31.5) | 489 (29.6) | |
| Chemotherapy | 0.797 | ||
| No/unknown | 4,189 (81.5) | 1,351 (81.8) | |
| Yes | 951 (18.5) | 301 (18.2) | |
| Invasion depth | 0.846 | ||
| <1 mm | 584 (11.4) | 190 (11.5) | |
| ≥1 mm | 1,733 (33.7) | 568 (34.4) | |
| Unknown | 2,823 (54.9) | 894 (54.1) | |
| Lymphadenectomy | 0.258 | ||
| No | 2,819 (54.8) | 912 (55.2) | |
| Yes | 2,279 (44.3) | 733 (44.4) | |
| Unknown | 42 (0.8) | 7 (0.4) | |
| SLNB | 0.125 | ||
| No | 4,755 (92.5) | 1,520 (92.0) | |
| Yes | 343 (6.7) | 125 (7.6) | |
| Unknown | 42 (0.8) | 7 (0.4) | |
| Surgery type | 0.146 | ||
| None | 1,036 (20.2) | 331 (20.0) | |
| LTE | 2,421 (47.1) | 822 (49.8) | |
| Vulvectomy | 667 (13.0) | 185 (11.2) | |
| Debulking | 1,016 (19.8) | 314 (19.0) | |
| FIGO stage | 0.809 | ||
| I | 1,838 (35.8) | 599 (36.3) | |
| II | 269 (5.2) | 85 (5.1) | |
| III | 772 (15.0) | 230 (13.9) | |
| IV | 1,008 (19.6) | 320 (19.4) | |
| Unknown | 1,253 (24.4) | 418 (25.3) | |
| AJCC stage | 0.926 | ||
| I | 2,129 (41.4) | 691 (41.8) | |
| II | 640 (12.5) | 195 (11.8) | |
| III | 892 (17.4) | 276 (16.7) | |
| IVA | 286 (5.6) | 93 (5.6) | |
| IVB | 195 (3.8) | 69 (4.2) | |
| Unknown | 998 (19.4) | 328 (19.9) | |
| T stage | 0.689 | ||
| T1 | 2,970 (57.8) | 963 (58.3) | |
| T2 | 1,134 (22.1) | 348 (21.1) | |
| T3 | 471 (9.2) | 151 (9.1) | |
| T4 | 71 (1.4) | 18 (1.1) | |
| TX | 494 (9.6) | 172 (10.4) | |
| N stage | 0.333 | ||
| N0 | 3,616 (70.4) | 1,165 (70.5) | |
| N1 | 711 (13.8) | 227 (13.7) | |
| N2 | 510 (9.9) | 150 (9.1) | |
| N3 | 54 (1.1) | 27 (1.6) | |
| NX | 249 (4.8) | 83 (5.0) | |
| M stage | 0.494 | ||
| M0 | 4,828 (93.9) | 1,543 (93.4) | |
| M1 | 209 (4.1) | 78 (4.7) | |
| MX | 103 (2.0) | 31 (1.9) | |
| Outcome | 0.500 | ||
| Alive | 3,099 (60.3) | 1,002 (60.7) | |
| Dead attributable to vulvar cancer | 1,290 (25.1) | 396 (24.0) | |
| Dead of other causes | 729 (14.2) | 243 (14.7) | |
| Dead of unknown reason | 22 (0.4) | 11 (0.7) | |
| Follow-up time (IQR), month | 20 (10–69) | 30 (9–70) |
IQR, interquartile range; SLNB, sentinel lymph node biopsy; FIGO, International Federation of Gynecology and Obstetrics; AJCC, American Joint Committee on Cancer.