Prediction of residual metabolic activity after treatment in NSCLC patients

Figures & data

Table I. Patient characteristics and their association with post-RT outcome in univariate analysis. Comparison of groups with residual disease and with complete metabolic response.

Variable	Residual disease (n = 56)	Complete metabolic response (n = 45)	p*	AUC
Age, years
Mean	65	65	0.907	0.54
SD	10.6	7.5
Gender
Female	21 (38)	19 (42)	0.480	0.54
Male	35 (62)	26 (58)
Stage
I	8 (14)	7 (16)	0.882	0.54
II	1 (2)	1 (2)
IIIA	13 (23)	9 (20)
IIIB	33 (59)	28 (62)
IV	1 (2)
Histology
SCC	17 (30)	7 (16)	0.327	0.54
Adenocarcinoma	9 (16)	11 (24)		0.56
Large cell	20 (36)	17 (38)		0.54
NSCLC, NOS	10 (18)	10 (22)		0.47
FEV 1
Mean	75.3	72.2	0.454	0.52
SD	16.8	22.5
WHO-PS
0	15 (27)	14 (31)	0.468	0.54
1	32 (57)	24 (53)
≥ 2	9 (16)	7 (16)
GTVprimary (cm^3) Mean	103.0	48.3	0.008	0.62
SD	126.13	55.5
GTVnodal (cm^3)
Mean	24.9	34.4	0.368	0.54
SD	37.3	66.5
Tumor load (cm^3)
Mean	127.8	82.2	0.047	0.60
SD	124.6	97.5
Chemotherapy
Yes	45 (80)	37 (82)	0.813	0.54
No	11 (20)	8 (18)
PLNS
0	12 (21)	12 (27)	0.929	0.54
1	13 (23)	12 (27)
2	22 (39)	11 (24)
3	6 (11)	4 (9)
≥ 4	3 (5)	6 (13)
SUVmax
Mean	10.5	7.7	0.007	0.64
SD	5.0	5.2
OTT (days)
Mean	24	27	0.013	0.60
SD	5	6
EQD2, T (Gy)
Mean	60.6	62.0	0.468	0.47
SD	9.5	9.2
Prescribed TTD (Gy)
Mean	61.0	61.5	0.809	0.54
SD	10.7	11.1

Abbreviations: TTD = Total tumor dose; OTT = Overall Treat ment Time; SUV_max = Standardized Uptake Value; EQD_{2, T} = Equivalent radiation dose at 2 Gy corrected for time; FEV₁ = Forced expiratory volume in 1 s; SCC = Squamous cell carcinoma; NOS = Not specified otherwise; WHO-PS = World Health Organization-performance status; PLNS = Positive lymph node stations.

*Comparison between residual disease group vs. complete metabolic response group for variables. The Mann-Whitney U test was used for continuous variables and the Chi-square test for categorical variables.

Figure 1. Kaplan-Meier estimates of overall survival of patients with residual metabolically active areas and with complete metabolic response on the post-radiotherapy PET-CT scan. Patients with residual metabolically active areas had significantly worse survival (p = 0.0001).

Figure 2. Survival among patients with advanced NSCLC for selected variables. For continuous variables, the cut-off value to stratify the patients was defined at the variable median. Shown are Kaplan-Meier curves for GTV_primary, SUV_max, OTT, EQD_{2, T}, TNM stage and age. In panel E, patients with stage I and II were grouped together due to the small number of cases. Stage IV (1 patient) was grouped with Stage IIIB.

Figure 3. Area under the ROC curve assessed by the leave-one-out method for the multivariate model consisting on GTV_primary, SUV_max, OTT and EQD_{2, T.} A classifier with sensitivity of 1 and (1-specificity) of 0, point (0, 1) in graph, is ideal.