TABLE 1.
Patient and Treatment Characteristics
| Characteristic | Prior trastuzumab (n = 19) | No prior trastuzumab (n = 14) | Total (n = 33) |
|---|---|---|---|
| Median age at diagnosis (y) | 59 (range, 40–76) | 59 (range, 34–79) | 59 (range, 34–79) |
| Patients with metastasis at diagnosis (n) | 17 (89) | 10 (71) | 27 (82) |
| Primary tumor site (n) | |||
| Esophageal | 2 (11) | 2 (14) | 4 (12) |
| GEJ (Siewert I-II) | 14 (74) | 7 (50) | 21 (64) |
| Gastric | 3 (16) | 5 (36) | 8 (24) |
| Method used to confirm sample is HER2+ (n) | |||
| FISH | 3 (16) | 3 (21) | 6 (18) |
| IHC | 15 (79) | 11 (79) | 26 (79) |
| NGS | 1 (5) | 0 (0) | 1 (3) |
| Patients with HER2 heterogeneity across samples (n) | 3 (16) | 6 (43) | 9 (27) |
| Patients receiving HER2-directed therapy at the time of scan (n) | 16 (84) | 14 (100) | 30 (91) |
| Median no. of lines of treatment at the time of HER2 PET | 3 (range, 2–6) | 1 (range, 1–2) | 2 (range, 1–6) |
| Median total lines of treatment received | 3 (range, 2–7) | 3 (range, 1–9) | 3 (range, 1–9) |
| Median time on treatment at the time of HER2 PET (d) | 93 (range, 0–212) | 394 (range, 7–1,410) | 126 (range, 0–1,410) |
| Total lesions detected on imaging (all patients) | |||
| Median, CT | 5 (range, 1–11) | 5.5 (range, 1–15) | 5 (range, 1–15) |
| Median, HER2 | 4 (range, 1–7) | 3.5 (range, 0–11) | 4 (range, 0–11) |
| Median, 18F-FDG PET | 6.5 (range, 1–13) | 7 (range, 1–14) | 7 (range, 1–14) |
| Patients with ≥ 1 lesion intense or very intense on HER2 PET (n) | 8 (42) | 7 (50) | 15 (45) |
| Median SUVmax per patient on HER2 PET | 7.8 (range, 3.20–23.8) | 9.8 (range, 0–22.2) | 9.2 (range, 0–23.8) |
| Median SUVmean per lesion on HER2 PET | 6.5 (range, 2.8–14.2) | 7.8 (range, 0–15.9) | 7.0 (range, 0–15.9) |
Data are number, with percentages in parentheses, or median, with the minimum to maximum in parentheses.
IHC = immunohistochemistry; NGS = next-generation sequencing.