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Overall Survival for Stage I Non-Small Cell Lung Cancer Treated with Radiotherapy Alone; a Single Institution Retrospective Study O. Holmes, G. Cook, R. MacRae, P. Cross and J. Pantarotto Division of Radiation Oncology, University of Ottawa
Introduction
Results II
Results III
Results IV
Radiotherapy has been an alternative curative treatment for non-operable early stage NSCLC for years
Standard fractionation (2Gy/fraction) improves median survival but offers little chance of cure
Stereotactic ablative radiotherapy (SABR) has been adopted as the technique of choice in for this patient population, particularly when tumours are less than 5cm in diameter
The proportion of patients treated with radiotherapy is growing, in part due to the increase in Stage I patients and the success of stereotactic ablative radiotherapy (SABR) programs for lung cancer
Approximately 400 patients with lung cancer are treated each year at our institution. We have been collecting patient outcomes for patients with medically inoperable stage I lung cancer since 1991.
We present an analysis of survival and recurrence for patients treated between and 2013
Table 3: Kaplan-Meier Numeric Outcomes Summary
At the time of this analysis, 56% (N = 348) of the patients have died. 78% (N=242) of the conventional group have died, and 34%(N=106) of the SABR group have died
8% (N=52) are lost to follow up (no data for ≥1 year). 11% (N=35) are lost from the conventional group and 5% (N = 17) are lost from the SABR group
36% (N=223) continue on follow up
Patient characteristics and tumour characteristics are shown in tables 1 and 2 respectively
Table 1: Patient Characteristics
Missing (Conv/SABR)
Total (n=623)
Conventional (n=312)
SABR (n=311)
p-Value
Age
0 (0/0)
74.7
0.8435
Gender
Female
355(57)
165(53)
190(61)
0.0387
Male
268(43)
147(47)
121(39)
Smoking Status
Never Smoker
14 (7/7)
23 (3.7)
11(3.5)
12(3.9)
0.826
Ex-Smoker
243(39)
124(40)
119(38)
Current Smoker
343(55)
170(54)
173(56)
Weight Loss
≤ 5%
21 (14/7)
470(75)
222(71)
248(80)
0.0092
>5%
132(21)
76(24)
56(18)
Performance Status 
ECOG 0-1
9 (4/5)
419(67)
191(61)
228(73)
<0.01
ECOG 2-4
195(31)
117(38)
78(25)
Charlson Comorbidity (CCI)
<3
428(69)
227(73)
201(65)
0.014 ≥3
83(27)
110(35)
Year Treated
before 2009
240(38)
240(77)
0(0)
2009 onward
383(61)
72(23)
311(100)
Figure 2: Median survival (by Kaplan-Meier method) for patients treated with radiotherapy at our institution as a function of the year they received their first radiotherapy fraction.
Conclusions
Methods
Our observed overall survival and disease free survival rates are comparable with other published reports
Distant metastases remains the primary mode of failure
Treatment outcomes for patients with medically inoperable stage I NSCLC have improved since the inception of SABR
Retrospective review is unable to identify other confounding factors that could impact survival for patient groups treated in two different eras
Our long term data for patients treated with SABR continues to mature
P < 0.01
An ethics-approved database with outcome data for 623 Stage I NSCLC patients treated with curative radiotherapy alone from 1994 to 2013 was queried
312 patients were treated with conventional radiotherapy (2—4 Gy/day) and 311 were treated with SABR (7.5 – 20 Gy/day)
Kaplan-Meier analysis was used to demonstrate the relationship between survival, and recurrence free survival and time for patients treated with conventional radiotherapy and conventional radiotherapy
The Log rank test was used to statistically compare outcomes between these groups
Table 2: Tumour Characteristics
Missing (Conv/SABR)
Total (n=623)
Conventional (n=312)
SABR (n=311)
p-Value
Histology
Adenocarcinoma
0 (0/0)
218(35)
61(20)
157(50)
<0.01
Squamous
150(24)
76(24)
74(24)
Other
255(41)
175(56)
80(26)
T Stage
T1a (≤2 cm)
223(36)
75(24)
148(48)
T1b (>2 cm, ≤3 cm)
215(35)
113(36)
102(33)
T2a (>3 cm, ≤ 5cm)
185(30)
124(40)
> 1 tumour
81 (13)
30 (9.6)
51 (16)
0.019
P = 0.07
References
Kaplan-Meier survival and disease free survival plots are shown in Figure 1. Corresponding numerical data is shown in Table 3
The median survival for patients treated with SABR is 4.8 years and 3.1 years for patients treated with conventional radiotherapy
The median survival is plotted as a function of the year of treatment in Figure 2
Results I
R Timmerman et al., Stereotactic body radiation therapy for inoperable early stage lung cancer. J Amer Med Assoc 2010;
J Nyman et al., Stereotactic hypofractionated radiotherapy for stage I non-small cell lung cancer –Mature results for medically inoperable patients. Lung Cancer 2006;51:
H Onishi H et al. Stereotactic hypofractionated high-dose irradiation for stage I nonsmall cell lung carcinoma. Clinical outcomes in 245 subjects in a Japanese multiinstitutional study. Cancer 2004;101(7);
Median follow up was 27 months (quartiles 18-40) for patients treated with SABR and 34 months (quartiles 17-57) for patients treated with conventional radiotherapy. Follow up time was significantly longer for patients treated with conventional radiotherapy (Wilcoxon signed rank test p = )
Figure 1: Kaplan-Meier survival (A) and disease free survival (B-D) curves comparing SABR and conventional radiotherapy. P-values are calculated by the Log-Rank method.
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