Table 4.

Patient/tumor characteristics stratified by tertiles of under-responding voxel percentages relative to prediction

% of Under-responding voxels
Variable<25% (N = 7)25%–75% (N = 9)>75% (N = 9)P
Female sex2 (28.6)7 (77.8)6 (66.7)0.20
Age, y60 (50–70)66 (59–75)58 (51–72)0.22
Adenocarcinoma (vs. squamous cell carcinoma)5 (71.4)7 (77.8)7 (77.8)>0.99
Stage IIIB (vs. other)3 (42.9)1 (11.1)4 (44.4)0.31
Proton beam therapy (vs. X-ray radiotherapy)6 (85.7)3 (33.3)3 (33.3)0.077
Chemotherapy modality>0.99
 Carboplatin + paclitaxel4 (57.1)6 (66.7)6 (66.7)
 Cisplatin + etoposide3 (42.9)3 (33.3)3 (33.3)
Primary MTV, cm327 (3–305)32 (16–396)25 (2–351)0.56
SUVmax, g/cm311 (6–32)10 (4–23)11 (3–23)0.95
SUVmean, g/cm35 (2–16)5 (2–12)6 (2–11)0.97
TLG, g204 (12–1,566)257 (38–4,408)247 (5–2,847)0.63
Ring/concave uptake pattern (vs. foci/convex)3 (42.9)5 (55.6)4 (44.4)>0.99
Time from pre-RT PET to mid-RT PET, d30 (23–44)26 (21–51)21 (16–44)0.23
Time from pre-RT PET to RT start, d14 (6–28)10 (5–33)5 (1–28)0.21
Number of fractions12(11–13)12 (11–13)12 (10–13)0.81
Mean dose, Gy24 (23–28)25 (23–28)25 (19–27)0.69
Mid-RT PET nonresponder0 (0.0)4 (44.4)6 (66.7)0.030
  • NOTE: Values are No. (%) or median (range) unless otherwise specified.