Table 1.
Baseline demographics a and clinical characteristics of patients with CUP, overall, and by receipt of anticancer pharmacotherapy.
| Overall | Histologically Confirmed |
Not Histologically Confirmed b |
||||
|---|---|---|---|---|---|---|
| Characteristic | n | % | n | % | N | % |
| Total number of patients | 4562 | 100.0 | 2813 | 100.0 | 1749 | 100.0 |
| Age at CUP diagnosis, years | ||||||
| Median (IQR) | 80 | 73.0–86.0 | 78 | 72.0–84.0 | 84 | 78.0–89.0 |
| Age groups, years | ||||||
| 66–74 | 1334 | 29.2 | 1018 | 36.2 | 316 | 18.1 |
| 75–84 | 1728 | 37.9 | 1133 | 40.3 | 595 | 34.0 |
| ≥85 | 1500 | 32.9 | 662 | 23.5 | 838 | 47.9 |
| Sex | ||||||
| Female | 2453 | 53.8 | 1449 | 51.5 | 1004 | 57.4 |
| Male | 2109 | 46.2 | 1364 | 48.5 | 745 | 42.6 |
| Race | ||||||
| White | 3936 | 86.3 | 2414 | 85.8 | 1522 | 87.0 |
| Black | 358 | 7.9 | 220 | 7.8 | 138 | 7.9 |
| Other/Unknown | 268 | 5.8 | 179 | 6.4 | 89 | 5.1 |
| Year of CUP diagnosis | ||||||
| 2013 | 1601 | 35.1 | 999 | 35.5 | 602 | 34.4 |
| 2014 | 1523 | 33.4 | 931 | 33.1 | 592 | 33.9 |
| 2015 | 1438 | 31.5 | 883 | 31.4 | 555 | 31.7 |
| Poverty indicator, c % | ||||||
| 0–<5 | 1024 | 22.5 | 664 | 23.6 | 360 | 20.6 |
| 5–<10 | 1072 | 23.5 | 671 | 23.9 | 401 | 22.9 |
| 10–<20 d | 1341 | 29.4 | 807 | 28.7 | 534 | 30.5 |
| 20–100 | 1125 | 24.7 | 671 | 23.9 | 454 | 26.0 |
| Unknown/Missing | S | S | S | S | S | S |
| Urban vs. rural | ||||||
| All urban d | 2667 | 58.5 | 1673 | 59.5 | 994 | 56.8 |
| Mostly urban | 1063 | 23.3 | 633 | 22.5 | 430 | 24.6 |
| Mostly rural | 392 | 8.6 | 245 | 8.7 | 147 | 8.4 |
| All rural | 440 | 9.6 | 262 | 9.3 | 178 | 10.2 |
| Unknown/Missing | S | S | S | S | S | S |
| Patient status at study end | ||||||
| Died | 4163 | 91.3 | 2479 | 88.1 | 1684 | 96.3 |
| Lost to follow-up | 399 | 8.8 | 334 | 11.9 | 65 | 3.7 |
| Overall | Treated e | Untreated f | ||||
| Characteristic | n | % | n | % | N | % |
| Total | 4562 | 100.0 | 621 | 100.0 | 3941 | 100.0 |
| NCI comorbidity score g | ||||||
| 0 | 1446 | 31.7 | 302 | 48.6 | 1144 | 29.0 |
| Low (1–<2) | 1035 | 22.7 | 163 | 26.3 | 872 | 22.1 |
| Middle (2–<4) | 932 | 20.4 | 96 | 15.5 | 836 | 21.2 |
| High (≥4) | 1149 | 25.2 | 60 | 9.7 | 1089 | 27.6 |
| Basis of diagnostic confirmation h | ||||||
| Histologic confirmation i | 2813 | 61.7 | 604 | 97.3 | 2209 | 56.1 |
| Imaging only j | 1336 | 29.3 | 13 | 2.1 | 1323 | 33.6 |
| Other k | 202 | 4.4 | S | S | 199 | 5.1 |
| Clinical only l | 211 | 4.6 | S | S | 210 | 5.3 |
| Histology (among those with histologic confirmation) | ||||||
| Adenocarcinoma | 1149 | 25.2 | 207 | 33.3 | 942 | 23.9 |
| Carcinoma, NOS m | 479 | 10.5 | 77 | 12.4 | 402 | 10.2 |
| Squamous-cell carcinoma, NOS | 312 | 6.8 | 97 | 15.6 | 215 | 5.5 |
| Neuroendocrine carcinoma | 177 | 3.9 | 69 | 11.1 | 108 | 2.7 |
| Small-cell carcinoma, NOS | 94 | 2.1 | S | S | S | S |
| Neoplasm, malignant | 148 | 3.2 | S | S | S | S |
| Other histology | 454 | 10.0 | 117 | 18.8 | 337 | 8.6 |
| Not histologically confirmed | 1749 | 38.3 | 17 | 2.7 | 1732 | 44.0 |
CUP, cancer-of-unknown-primary-origin; IQR, interquartile range; NCI, National Cancer Institute; NOS, not otherwise specified; SEER, Surveillance, Epidemiology, and End Results; SEERM, Surveillance, Epidemiology, and End Results–Medicare. S denotes suppressed data based on NCI guidelines for confidentiality. a Based on SEERM cancer registry data. b Identification via imaging only (radiology/other imaging techniques without histologic confirmation), other (positive laboratory test/marker study; direct visualization without histologic confirmation), or clinical diagnosis only (other than imaging only or other). c The poverty indicator denotes the proportion of the population that lives below the federal poverty line in the patient’s census tract. A total of 0%–<5% poverty represents wealthier census tracts where most people are above the poverty line and 20% to 100% poverty groups represent less wealthy tracts. d Suppressed rows are added to the most populous row here for privacy reasons. e Patients receiving anticancer pharmacotherapy. f Patients not receiving anticancer pharmacotherapy. g Score based on the number of comorbid conditions. h Based on SEER registry data. I Positive histology (for a malignant tumor) only, positive cytology only, or positive histology plus positive immunophenotyping and/or positive genetic studies. j Radiology and other imaging techniques without histologic confirmation. k Positive laboratory test/marker study; direct visualization without histologic confirmation. l Clinical diagnosis only (other than imaging only or other). m Carcinoma NOS was documented where there was a lack of information available in the files of the patient.