Journal Thoracic Oncology

Abstracts Journal of Thoracic Oncology • Volume 12 Issue S1 January 2017
examination. 3 The Fleischner Society for Thoracic Imaging and Diagnosis uses
a cutoff diameter of 5 mm for decision making for subsolid nodules. 2 It should
be kept in mind that solid nodules that are suspicious for lung cancer are
frequently invasive. A subsolid nodule can be classified as a pure ground glass
nodule (GGN) or part-solid nodule. Subsolid nodules grow slowly and may
develop a solid component. The HRCT findings of early lung adenocarcinomas
were significantly correlated with the histopathologic findings of the
resected specimens. 5 In the evaluation of subsolid nodules, the features
indicating noninvasive lung adenocarcinoma include tumor disappearance
rate, diameter of consolidation, and GGO ratio. 6 However, even HRCT cannot
accurately assess the areas of solid opacities or GGO, and results might vary
between investigators. In the upcoming 8 th TNM classification, the Lung
Cancer Staging Project of the International Association for the Study of Lung
Cancer showed that the solid part of a nodule on HRCT represents the clinical
T factor, and that measurement of the solid part is essential for lung cancer
staging. 5 Positron emission tomography (PET)-CT has a clearly established
role in lung cancer clinical practice. Based on the pretest probability, PET-CT
should be used for patients with a solid, indeterminate nodule > 8 mm in
size. 3,4 For adenocarcinomas in situ (AIS) and minimally invasive
adenocarcinomas (MIA) of the lung that show solid opacities on HRCT, the
preoperative PET-CT and thin-section CT findings together can provide
information on the aggressiveness of the tumor. Our study group found that
these modalities used together could detect aggressive lung cancers in clinical
stage IA (Fig. 1). 7 However, since PET-CT can show false-negative results for
slow-growing and low-grade lung malignancies, we think that HRCT is the best
modality for identifying indolent lung cancers. Transthoracic biopsy,
bronchoscopy, or surgery is used for obtaining specimens for
histopathological diagnosis. The definitive diagnosis of small pulmonary
nodules, especially GGO-dominant nodules, is challenging. The diagnostic
yields of percutaneous CT-guided fine needle aspiration biopsy for GGOdominant
and solid-dominant lesions were 51.2% and 75.6%, respectively (p =
0.018). 9 The diagnostic yield of GGO-dominant lesions < 10 mm was 35.2%.
Since invasive biopsy is not without risk, a histopathological diagnosis should
be limited to nonsurgical candidates. For cases with high likelihood of lung
cancer, a surgical biopsy followed by lung resection might be warranted.
Although surgery might be performed on patients with benign nodules, it
does provide the definitive diagnosis. If surgery is performed after careful
preoperative assessment, the surgical mortality is very low, and the surgical
risk may be acceptable. Treatment: While lobectomy is the standard
procedure for lung cancers, sublobar resection, meaning segmentectomy or
wedge resection, might be justified for patients with noninvasive small lung
cancers. However, to date, which procedure, sublobar resection or lobectomy,
provides a better outcome remains unclear in these cases, since prospective
randomized control trials are ongoing (JCOG0802/WJOG4607L 8 and
CALGB140503). One of the concerns in sublobar resection is recurrence at the
surgical margin (Fig. 2). Recurrence at the surgical margin might be accounted
for by tumor cells spreading via air spaces. 10 Accurate intraoperative cytology
and adequate surgical margins have been reported to be important for
preventing recurrence at the surgical margin. Another concern is lymph node
metastasis. In a prospective radiological study for clinical stage IA lung cancer,
47 of 545 (8.6%) patients had lymph node metastasis. 6 Sublobar resection,
especially wedge resection, dose not allow evaluation of lymph nodes for
metastatic disease. Conclusion: HRCT findings play an important role in
discriminating the biological behaviors of pulmonary nodules. The definitive
diagnosis by HRCT can be difficult, and the combination of HRCT and PET-CT
might be beneficial. Randomized control trials should clarify the role of
sublobar resection in treating patients with noninvasive lung cancer. Figure 1.
Figure 2.
References 1. Ost D, Fein AM, Feinsilver SH. The solitary pulmonary nodule.
N Engl J Med 2003;348:2535-42. 2. Naidich D, Bankier AA, MacMahon H,
Schaefer-Prokop CM, Pistolesi M, Goo JM, et al. Recommendations for the
management of subsolid pulmonary nodules detected at CT: A statement
from the Fleischner Society. Radiology 2013;266:304-17. 3. Gould MK,
Donington J, Lunch WR, Mazzone PJ, Midthun DE, Naidich DP, et al. Evaluation
of individuals with pulmonary nodules: when is it lung cancer? Diagnosis and
management of lung cancer 3rd ed: American College of Chest Physicians
evidence-based clinical practice guidelines. Chest 2013;143:e93s-120s.
4. National Comprehensive Cancer Network. Guidelines for surveillance
following therapy for non-small cell lung cancer Ver 4.2016. Available at: www.
nccn.com. 5. Travis WD, Asamura H, Bankier AA, Beaseley MB, Detterbeck
F, Flieder DB, et al. The IASLC Lung Cancer Staging Project: Proposals for
coding T categories for subsolid nodules and assessment of tumor size in
part-solid tumors in the forthcoming eighth edition of the TNM classification
of lung cancer. J Thorac Oncol 2016;11:1204-23. 6. Suzuki K, Koike T, Asakawa
T, Kusumot M, Asamura H, Nagai K, et al. A prospective radiological study of
thin-section computed tomography to predict pathological noninvasiveness
in peripheral clinical IA lung cancer (Japan Clinical Oncology Group 0201). J
Thorac Oncol 2011;6:751-6. 7. Shiono S, Yanagawa N, Abiko M, Sato T. Detection
of non-aggressive stage IA lung cancer using chest computed tomography and
positron emission tomography/computed tomography. Interact Cardiovasc
Thorac Surg. 2014;21:637-43. 8. Nakamura K, Saji H, Nakajima R, Okada
M, Asamura H, Shibata T et al. A phase III randomized trial of lobectomy
versus limited resection for smallsized peripheral non-small cell lung cancer
(JCOG0802/WJOG4607L). Jpn J Clin Oncol 2010;40:271–4. 9. Shimizu K, Ikeda N,
Tsuboi M, Hirano T, Kato H. Percutaneous CT-guided fine needle aspiration for
lung cancer smaller than 2 cm and revealed by ground-glass opacity at CT. Lung
Cancer 2006;51:173-9. 10. Shiono S, Yanagawa N. Spread through air spaces
is a predictive factor of recurrence and a prognostic factor in stage I lung
adenocarcinoma. Interact Cardiovasc Thorac Surg. 2016 Jun 26. pii: ivw211.
Keywords: pulmonary nodules, computed tomography, sublobar resection,
lung cancer
SC24: MANAGEMENT OF INDETERMINATE PULMONARY NODULES
WEDNESDAY, DECEMBER 7, 2016 - 11:00-12:30
SC24.02 RADIOLOGICAL TECHNIQUES FOR THE EVALUATION OF
PULMONARY NODULES
Reginald Munden
Radiologic Sciences, Wake Forest Baptist Medical Center, Winston-Salem/NC/
United States of America
Radiologic Techniques for the Evaluation of Pulmonary Nodules The incidental
detection of pulmonary nodules has increased with improved CT technology
and thin section imaging techniques 1,2 . Adding to this increased detection of
nodules is the heightened interest in the purposeful search for nodules such
as in oncology patients and lung cancer screening programs. The management
of CT detected nodules is a subject of much debate and dependent upon the
clinical setting. For instance, in a lung cancer screening setting, there has
been a large volume of investigation of solid, semi-solid and ground glass
nodules that is the foundation of management recommendations such as
LungRads 3 . In patients with a known malignancy, there is minimal literature
on management recommendations and thus more influenced by pulmonary
metastatic potential of the malignancy and clinician experience 4 . Finally
incidentally detected nodule management is greatly influenced by cancer
risk factors and nodule texture; for these situations, the Fleischner criteria
have been the most widely used and accepted management guidelines 5 . The
radiologic evaluation of nodules most often utilizes conventional imaging
techniques of chest radiographs, computed tomography (CT), PET/CT.
Occasionally MRI and ultrasound may be employed. Most recent changes
involve risk stratification, computer software applications to enhance nodule
analysis such as nodule enhancement patterns, volumetric computations,
and texture analysis 6-8 . Future directions include incorporation of genomics
into imaging as well as radiomic analysis and machine learning 9,10 . This
S68 Journal of Thoracic Oncology • Volume 12 Issue S1 January 2017