Table 2.
Baseline patient, tumor, and treatment characteristics for all patients (n = 115) and broken down by patients did or did not experience SL
| Characteristic | Total (N = 115) | SL (N = 63) | No SL (N = 52) | P value |
|---|---|---|---|---|
| Age at diagnosis, years, Median (IQR) | 63.00 (59.00–67.00) | 63.00 (60.00–67.00) | 62.50 (55.50–67.00) | 0.362 |
| Sex | ||||
| Male | 107 (92.2%) | 59 (51.3%) | 48 (41.7%) | |
| Female | 8 (7.0%) | 4 (3.5%) | 4 (3.5%) | 0.778 |
| ECOG performance status | ||||
| 0–1 | 84 (73.0%) | 44 (38.3%) | 40 (34.8%) | |
| 2 | 31 (27.0%) | 19 (16.5%) | 12 (10.4%) | 0.394 |
| Smoking pack-years | ||||
| ≥ 10 | 80 | 45 | 35 | |
| 0–10 | 4 | 3 | 1 | |
| 0 | 24 | 12 | 12 | |
| Unkown | 7 | 3 | 4 | 0.717 |
| Histology | ||||
| Squamous carcinoma | 78 (67.8%) | 49 (42.2%) | 35 (30.4%) | |
| Adenocarcinoma | 34 (29.6%) | 19 (16.5%) | 15 (13.0%) | |
| Others | 3 (2.6%) | 1 (0.9%) | 2 (1.7%) | 0.683 |
| cT stage (AJCC 8th ed) | ||||
| T1 | 14 (12.2%) | 8 (7.0%) | 6 (5.2%) | |
| T2 | 31 (26.7%) | 20 (17.2%) | 11 (9.57%) | |
| T3 | 27 (23.5%) | 12 (10.4%) | 15 (13.0%) | |
| T4 | 43 (37.4%) | 23 (20.0%) | 20 (17.4%) | 0.492 |
| cN stage | ||||
| N1 | 6 (5.2%) | 2 (1.7%) | 4 (3.5%) | |
| N2 | 73 (63.5%) | 39 (33.9%) | 34 (29.6%) | |
| N3 | 36 (31.3%) | 22 (19.1%) | 14 (12.2%) | 0.417 |
| Stage | ||||
| IIIA | 33 (28.7%) | 18 (15.7%) | 15 (13.0%) | |
| IIIB | 61 (53.0%) | 33 (28.7%) | 28 (24.3%) | |
| IIIC | 21 (18.3%) | 12 (10.4%) | 9 (7.8%) | 0.971 |
| TLCs, cells/μL (median, IQR) | ||||
| Baseline | 1600 (1400–2000) | 1600 (1300–1900) | 1800 (1400–2200) | 0.037 |
| Pre-RT | 1800 (1400–2100) | 1600 (1280–1900) | 1965 (1700–2252) | < 0.001 |
| TLC nadir during the course of RT | 500 (380–700) | 390 (300–470) | 700 (600–830) | < 0.001 |
| 1 month after RT | 915 (700–1100) | 800 (598–1100) | 995 (882–1232) | 0.004 |
| 2 month after RT | 900 (700–1100) | 740 (600–982) | 1000 (810–1195) | < 0.001 |
| Tumor volume, cm3 (median, IQR) | ||||
| GTV | 56.85 (32.47–129.35) | 87.69 (45.58–144.92) | 43.40 (21.84–95.52) | 0.006 |
| PTV | 146.03 (74.20–247.39) | 160.95 (80.69–258.92) | 124.82 (71.13–224.05) | 0.192 |
| EQD2 (Gy or Gy[RBE]) (median, IQR) | 64.00 (60.00–65.00) | 62.87 (60.00–65.10) | 65.00 (60.00–65.00) | 0.755 |
| BED (Gy) | 76.80 (72.00–78.00) | 75.44 (72.00–78.13) | 78 (72–78) | 0.768 |
| Fractions, number (median, IQR) | 25 (20–30) | 25 (25–30) | 25 (20–30) | 0.141 |
| OTT, days (median, IQR) | 39 (31–43) | 39 (33–43) | 35 (29–43) | 0.281 |
| Key mean normal tissue doses, cGy (median, IQR) | ||||
| Mean lung dose | 1275 (1078–1454) | 1354.90 (1146.00–1480.00) | 1165 (990–1386) | 0.007 |
| Mean heart dose | 601 (420–1261.50) | 886 (439.00–1502.25) | 518 (384–936.90) | 0.041 |
| Radiation technique | ||||
| 3D conformal | 28 (24.3%) | 16 (13.9%) | 12 (10.4%) | |
| Intensity modulated | 37 (32.2%) | 19 (16.5%) | 18 (15.7%) | |
| Helical Tomotherapy | 50 (43.5%) | 28 (24.3%) | 22 (19.1%) | 0.874 |
| Concurrent chemoradiation (sequential) | ||||
| Yes | 31 (27.0%) | 15 (12.9%) | 16 (13.9%) | |
| No | 84 (73.0%) | 48 (41.7%) | 36 (31.3%) | 0.403 |
| Induction chemotherapy | ||||
| Yes | 91 (79.1%) | 54 (47.0%) | 37 (32.2%) | |
| No | 24 (20.9%) | 9 (7.8%) | 15 (13.0%) | 0.056 |
| Adjuvant chemotherapy | ||||
| Yes | 61 (53.0%) | 31 (27.0%) | 30 (26.1%) | |
| No | 54 (47.0%) | 32 (27.8%) | 22 (19.1%) | 0.364 |
Abbreviations: SL severe lymphopenia, IQR interquartile range, ECOG Eastern Cooperative Oncology Group, AJCC American Joint Committee on Cancer, TLCs total peripheral lymphocyte counts, GTV gross tumor volume, PTV planning target volume, EQD2 equivalents (relative biological equivalents), BED biological effective dose, OTT overall treatment time