Table 1.
Baseline characteristics of patients diagnosed with Lynch syndrome at KPNC with or without a diagnosis of gastric or small intestinal cancer
| Characteristic | Totala, n (%) | Patients with gastric cancer, n (%) | Patients with small intestinal cancer, n (%) | Patients without either cancer, n (%) |
| All | 1,106 (100.0) | 11 (100.0) | 11 (100.0) | 1,085 (100.0) |
| Age range of cancer diagnosis, yr | — | 34–79 | 47–76 | — |
| Median age at gastric or small intestinal cancer diagnosis, yr (IQR) | — | 56 (42–63) | 57 (50–66) | — |
| Sex | ||||
| Female | 729 (65.9) | 4 (36.4) | 2 (18.2) | 723 (66.6) |
| Male | 377 (34.1) | 7 (63.6) | 9 (81.8) | 362 (33.4) |
| Race and ethnicity | ||||
| Asian | 164 (14.8) | 0 | 0 | 164 (15.1) |
| Black | 33 (3.0) | 1 (9.1) | 0 | 32 (3.0) |
| Hispanic | 173 (15.6) | 4 (36.4) | 2 (18.2) | 167 (15.4) |
| Non-Hispanic White | 660 (59.7) | 6 (54.6) | 8 (72.7) | 647 (59.6) |
| Other | 76 (6.9) | 0 | 1 (9.1) | 75 (6.9) |
| MMR gene | ||||
| MLH1 | 257 (23.2) | 2 (18.2) | 3 (27.3) | 252 (23.2) |
| MSH2/EPCAM | 295 (26.7) | 8 (72.7) | 6 (54.6) | 282 (26.0) |
| MSH6 | 241 (21.8) | 0 | 1 (9.1) | 240 (22.1) |
| PMS2 | 313 (28.3) | 1 (9.1) | 1 (9.1) | 311 (28.7) |
| Family history of gastric cancer | ||||
| 1st-degree relative | ||||
| No | 1,061 (95.9) | 11 (100.0) | — | 1,041 (95.9) |
| Yes | 45 (4.1) | 0 | — | 44 (4.1) |
| 2nd-degree relative | ||||
| No | 991 (89.6) | 9 (81.8) | — | 973 (89.7) |
| Yes | 115 (10.4) | 2 (18.2) | — | 112 (10.3) |
| History of Helicobacter pylori infection | ||||
| Not tested | 550 (49.7) | 1 (9.1) | 4 (36.4) | 545 (50.2) |
| H. pylori negative | 432 (39.1) | 4 (36.4) | 5 (45.5) | 423 (39.0) |
| H. pylori positive | 124 (11.2) | 6 (54.6) | 2 (18.2) | 117 (10.8) |
| Serological methods | 52 (4.7) | 4 (36.4) | 2 (18.2) | 47 (4.3) |
| Nonserological methods | 72 (6.5) | 2 (18.2) | 0 (0.0) | 70 (6.5) |
| Smoking | ||||
| Never | 678 (61.3) | 6 (54.5) | 4 (36.4) | 668 (61.6) |
| Ever | 428 (38.7) | 5 (45.5) | 7 (63.6) | 417 (38.4) |
IQR, interquartile range; KPNC, Kaiser Permanente Northern California; MMR, mismatch repair; PVs, pathogenic variants.
a
One patient developed both gastric cancer and intestinal cancer. MSH2/EPCAM data included 6 patients with PVs in EPCAM, none of whom developed gastric or intestinal cancer.