Stereotactic Ablative Body Radiotherapy Versus Conventionally Fractionated Radiotherapy for early Stage Large Cell Neuroendocrine Carcinoma of the Lung

Figures & data

Figure 1. CONSORT diagram showing selection criteria.

Table 1. Patient characteristics (n = 754).

Characteristics	Number (%)
Sex
Males	389 (52)
Females	365 (48)
Race
White	664 (88)
African American	77 (10)
Other	13 (2)
Comorbidity score
0	467 (62)
1	170 (22)
≥2	117 (16)
Insurance
Not insured	9 (1)
Private payer	115 (15)
Government	620 (82)
Unrecorded	10 (2)
Education %
≥29	156 (21)
20–28.9	210 (28)
14–19.9	251 (33)
<14	137 (18)
Treatment facility type
Community cancer program	65 (9)
Comprehensive community cancer program	429 (57)
Academic/research program	260 (34)
Treatment facility location
Metro	599 (79)
Urban	131 (17)
Rural	24 (4)
Income ($USD ^† )
<30,000 30,000–35,000 35,000–45,999	195 (26) 204 (27) 193 (26)
>46,000	162 (21)
Distance to treatment facility (miles)
≤10 >10	377 (50) 377 (50)
Age distribution (years)
≤73	399 (53)
>73	355 (47)
Grade
Well differentiated	3 (1)
Moderately differentiated	8 (1)
Poorly differentiated	371 (49)
Not recorded	372 (49)
Year of diagnosis
2004–2006	237 (31)
2007–2009	248 (33)
2010–2012	173 (23)
2013–2014	96 (13)
T stage
1	416 (55)
2	338 (45)
Chemotherapy
No	512 (68)
Yes	242 (32)
Treatment
SABR	238 (32)
CFRT	516 (68)

Education quantified as percentage of individuals from that zip code with less than a high school diploma.

^† Median income quantified by patient zip code.

CFRT: Conventionally fractionated radiation therapy; SABR: Stereotactic ablative body radiotherapy.

Table 2. Multivariable logistic regression for stereotactic ablative body radiotherapy.

Characteristics	Odds ratios (95% CI)	p-value
Sex
Males	Reference
Females	0.83 (0.56–1.24)	0.37
Race
White	Reference
African American	1.57 (0.83–3.00)	0.17
Other	0.75 (0.16–3.50)	0.71
Comorbidity score
0	Reference
1	1.01 (0.63–1.63)	0.97
≥2	0.79 (0.46–1.36)	0.27
Insurance
Not insured	Reference
Private payer	0.90 (0.12–6.76)	0.92
Government	1.27 (0.18–9.03)	0.81
Unrecorded	2.77 (0.23–33.46)	0.42
Education %
≥29	Reference
20–28.9	1.38 (0.75–2.55)	0.30
14–19.9	1.87 (0.91–3.82)	0.09
<14	1.96 (0.82–4.70)	0.13
Treatment facility type
Community cancer program	Reference
Comprehensive community cancer program	2.48 (1.02–6.00)	0.04*
Academic/research program	4.64 (1.86–11.56)	0.0010*
Treatment facility location
Metro	Reference
Urban	0.72 (0.40–1.33)	0.30
Rural	1.35 (0.45–4.02)	0.59
Income ($USD ^† )
<30,000 30,000–35,000 35,000–45,999 >46,000	Reference 1.27 (0.69-2.35) 1.59 (0.78-3.25) 0.92 (0.40–2.11)	0.44 0.20 0.84
Distance to treatment facility (miles)
≤10 >10	Reference 2.09 (1.35-3.25)	0.0010*
Age distribution (years)
≤73	Reference
>73	0.80 (0.52–1.22)	0.30
Grade
Well differentiated	Reference
Moderately differentiated	0.52 (0.01–33.16)	0.76
Poorly differentiated	0.89 (0.02–32.90)	0.95
Year of diagnosis
2004–2006	Reference
2007–2009	7.98 (4.30–14.86)	<0.0001*
2010–2012	11.44 (5.90–22.17)	<0.0001*
2013–2014	22.24 (10.55–46.89)	<0.0001*
T stage
1	Reference
2	0.41 (0.27–0.62)	<0.0001*
Chemotherapy
No	Reference
Yes	0.15 (0.09–0.26)	<0.0001*

*p values less than or equal to 0.05.

Education quantified as percentage of individuals from that zip code with less than a high school diploma.

^† Median income quantified by patient zip code.

Table 3. Multivariable Cox regression.

Characteristic	Hazard ratio (95% CI)	p-value
Age (years)
≤74	Reference
>74	1.24 (1.04–1.47)	0.015
Education (% ^† )
≥29	Reference
20–28.9	1.17 (0.90–1.52)	0.24
14–19.9	1.19 (0.87–1.62)	0.28
<14	1.29 (1.05–1.59)	0.016
Treatment
SBRT	Reference
CFRT	1.21 (1.00–1.46)	0.046
Gender
Males	Reference
Females	0.70 (0.59–0.83)	<0.0001
T stage
T1	Reference
T2	1.35 (1.13–1.59)	0.0005

^† Education quantified as percentage of individuals from that zip code with less than a high school diploma.

CFRT: Conventionally fractionated radiation therapy; SABR: Stereotactic ablative body radiotherapy.

Figure 2. Propensity matched Kaplan–Meier curve showing benefit to stereotactic ablative body radiotherapy with a median overall survival 34.7 versus 23.7 months; p = 0.02.

CFRT: Conventionally fractionated radiation therapy; SABR: Stereotactic ablative body radiotherapy.