Table 1.
Selected baseline characteristics for study population by study groups, the Surveillance, Epidemiology, and End Results (SEER) database, 2010‐2012
| Characteristic | Before PSM | After PSMa | ||||
|---|---|---|---|---|---|---|
| No RT (n = 20 878) | RT (n = 16 129) | P b | No RT (n = 10 583) | RT (n = 10 583) | P b | |
| Age [Years, mean (SD)] | 68.9 (11.2) | 64.7 (10.9) | <0.001 | 66.7 (11.1) | 66.4 (11.2) | 0.042 |
| Sex (Female, %) | 44.9 | 43.8 | 0.043 | 43.2 | 44.0 | 0.280 |
| Race (White, %) | 77.7 | 78.4 | 0.108 | 78.3 | 76.6 | 0.005 |
| Marital (Married, %) | 47.7 | 52.3 | <0.001 | 49.4 | 49.5 | 0.901 |
| Histology (%) | ||||||
| AD | 58.4 | 55.0 | <0.001 | 56.1 | 55.9 | 0.206 |
| SQC | 18.1 | 21.2 | 19.8 | 20.6 | ||
| Other | 4.9 | 4.4 | 4.6 | 4.5 | ||
| LCC | 2.3 | 2.5 | 2.4 | 2.5 | ||
| Unspecified | 16.3 | 16.8 | 17.1 | 16.5 | ||
| Grade (%) | ||||||
| 1 | 2.7 | 1.8 | <0.001 | 1.9 | 2.0 | 0.305 |
| 2 | 10.3 | 11.2 | 11.6 | 11.3 | ||
| 3 | 24.7 | 29.2 | 28.2 | 29.2 | ||
| 4 | 1.6 | 1.7 | 1.6 | 1.8 | ||
| Unknown | 60.8 | 56.1 | 56.7 | 55.6 | ||
| T (%) | ||||||
| T0‐T2 | 31.0 | 35.2 | <0.001 | 33.5 | 34.3 | 0.119 |
| T3‐T4 | 53.0 | 55.0 | 55.9 | 54.6 | ||
| Unknown | 16.0 | 9.8 | 10.6 | 11.2 | ||
| N (%) | ||||||
| N0 | 26.2 | 21.2 | <0.001 | 21.6 | 22.1 | 0.098 |
| N1 | 7.2 | 8.3 | 8.0 | 8.3 | ||
| N2 | 41.3 | 46.7 | 45.4 | 43.9 | ||
| N3 | 17.5 | 19.4 | 20.1 | 20.1 | ||
| Unknown | 7.8 | 4.4 | 4.9 | 5.5 | ||
| Number of metastatic sites of lung, brain, bone and liver (%)c | ||||||
| 0 | 32.8 | 16.2 | <0.001 | 25.7 | 24.1 | 0.029 |
| 1 | 46.0 | 49.7 | 46.6 | 46.8 | ||
| 2 | 15.9 | 23.9 | 20.4 | 21.4 | ||
| 3 | 4.6 | 8.3 | 6.0 | 6.4 | ||
| 4 | 0.7 | 1.8 | 1.4 | 1.2 | ||
| Bone metastasis (Yes, %)d | 30.1 | 44.7 | <0.001 | 44.3 | 43.9 | 0.472 |
| Brain metastasis (Yes, %)d | 10.9 | 44.4 | <0.001 | 21.2 | 23.6 | <0.001 |
| Liver metastasis (Yes, %)d | 20.1 | 15.3 | <0.001 | 16.8 | 17.9 | 0.034 |
| Lung metastasis (Yes, %)d | 33.3 | 25.5 | <0.001 | 28.4 | 28.7 | 0.616 |
| Chemotherapy (Yes, %) | 56.2 | 37.8 | <0.001 | 56.7 | 54.9 | 0.010 |
| Surgery (Yes, %) | 3.8 | 3.2 | 0.002 | 3.2 | 3.3 | 0.462 |
n, number of cases/controls; PSM, propensity score matching; RT, radiotherapy; AD, adenocarcinoma; SQC, squamous cell carcinoma; Other, other specified carcinoma; LCC, large cell carcinoma; Unspecified, unspecified malignant neoplasm.
PSM were done using variables including: age, gender, race, marital, histological types, grade, T stage, N stage, chemotherapy, surgery, radiotherapy, and metastatic sites of bone, brain, liver, and lung.
Derived from ANOVA for continuous variables and X 2 test for categorical variables.
Number of distant metastasis include four sites of distant metastasis at diagnose SEER provided: bone; brain; liver; lung.
Bone, brain, liver, and lung are four sites of distant metastasis at diagnose SEER provided.