Keywords:
Cancer, Stereotactic radiotherapy, Observer performance, Comparative studies, CT, Thorax, Oncology
Authors:
N. F. C. Guerreiro1, K. Giassi1, B. S. P. Oliveira2, K. Schoen3, N. Horvat1, H. Lee4, F. Miranda1, Y. Fábio1, V. A. Carlos Eduardo1; 1São Paulo/BR, 2Sao Paulo, Sao Paulo/BR, 3Curitiba, Paraná/BR, 4Sao Paulo, SP/BR
DOI:
10.26044/ecr2019/C-2141
Results
Population and Clinical Data
54 patients were included in the study,
40 (74.1%) men and 14 (25.9%) women,
with mean age of 76.5 years old (IQR: 69-82).
Eight patients had no comorbidity (14.8%),
18 (33.4%) had one comorbidity,
while 28 (51.8%) had more than one. Smoking was present in 40 (74.1%) patients.
Adenocarcinoma was the tumor histology in 43 (79.6%),
squamous cell carcinoma in 9 (16.7%) and 2 (3.7%) patients had other histologic diagnosis.
35 (66.7%) were at clinical staging IA at the time of the treatment; 13 (24.1%) were at staging IB; one patient at staging II and two patients were at staging III.
The tumor size median was 2.1 cm (IQR: 2.7–3.1).
Regarding treatment,
34 (62.9%) had no previous treatment before SBRT,
nine (16.0%) were submitted to previous chemotherapy,
three (5.0%) had previous radiotherapy and five (9.1%) had performed a previous surgery.
SBRT and CT evaluation
The median SBRT treatment time was 7 months (IQR 7-10 months) with a median dose of 54Gy (IQR 45-54).
The median dose per fraction was 18 Gy (IQR: 15-18).
59 CT scans were performed < 6 months after SBRT and 143 > after 6 months.
Seven patients had recurrence confirmed on lung biopsy during follow-up.
Median early CT evaluation was in 3 months (IQR: 1-4) and late CT evaluation in 11.5 months (IQR: 9-22).
Regarding the CT findings and considering the senior reader,
35 (68.1%) had early CT changes and 53 (98.1%) had late CT changes. The most prevalent early change was diffuse consolidation in 26 (48.1%) patients,
followed by patchy GGO.
Patchy consolidation was not present among any readers.
The most prevalent late change was modified conventional pattern in 25 (46.3%) patients.
Table 4 displays the distribution of CT findings described by each reader.
We found a strong agreement among all the readers for all findings in both early and late periods,
except for a low agreement,
but still substantial,
among the intermediate and senior readers on diffuse consolidation (K=0.65).
There were no differences between the readers in the Wilcoxon test.
Table 5 demonstrates the inter-reader agreement among the radiologists.
Recurrence was found in seven patients,
with enlarging opacity present in five (71%),
bulging margins in two (28%),
and loss of air bronchogram also in two (28%) patients.
Pleural effusion was not present in any patient.
These CT features were associated to recurrence with a p value < 0,001,
as shown in Figure 5.