The Journal of the Arkansas Medical Society Issue 9 Vol 114 | Page 18
SCIENTIFIC ARTICLE
Prevalence and Characteristics of Primary Lung
Cancer Among Large Lung Masses
Kshitij Chatterjee, MD 1 ; Nishi Shah, MD 1 ; Amy Joiner, MD 2 ; Yogita Rochlani, MD 1 ; Nikhil Meena, MD, FCCP 1,3
Department of Internal Medicine, UAMS
1
Department of Pathology, UAMS
2
Division of Pulmonary and Critical Care Medicine, Department of Medicine, UAMS
3
ABSTRACT
Background and objective: Lung
mass has been traditionally defined as
a focal pulmonary lesion > 3 cm and
is considered malignant until proven
otherwise. There is a lack of recent data on
prevalence of primary lung cancer among
lung masses. We attempt to establish the
proportion of lung masses that are primary
lung cancer and determine their CT char-
acteristics.
Methods: Patients with a lung mass
were classified in three groups: primary
lung cancer, non-lung cancer malignancy,
and benign or infectious causes; and CT
findings were compared among them.
Results: About 63% of lung masses
represented primary lung cancer, 18%
were non-lung cancer malignancies, and
18% accounted for benign tumors and in-
fectious pathologies. A mass that crossed
anatomical boundaries on CT was more
likely to represent lung cancer (OR 5.54
{1.47-20.86}, p=0.01).
Conclusion: Although lung carcinoma
remains the most common pathology
among lung masses, a significantly in-
creasing proportion of masses now repre-
sent benign and infectious etiologies.
Keywords/MeSH terms: Biopsy,
needle; diagnostic imaging; granuloma/
pathology; lung neoplasms; lung/radiog-
raphy.
INTRODUCTION (approval number 202086).
olitary pulmonary nodule (SPN)
has been well defined in litera-
ture as a spherical, well-circum-
scribed, radiographic opacity less than
or equal to 3 cm surrounded by aerated
lung; without associated adenopathy, at-
electasis or pleural effusion. 1 Focal lesions Population: Retrospective chart review
was performed on all patients who underwent
transthoracic needle aspiration (TTNA) or
endobronchial ultrasound-guided trans-bronchial
needle aspiration (EBUS-TBNA) at our institution
between Jan. 1, 2009 and Dec. 31, 2012. Cases
where thoracic CT scans were not available for re-
view or size of lesion was not documented were
excluded. Cases where a lung mass (>3 cm) was
sampled were identified. These cases were cat-
egorized in three groups based on the final patho-
logical diagnosis: (1) primary lung cancer; (2) non-
lung cancer malignancy; and (3) benign or infec-
tious pathologies.
S
larger than 3 cm are described as lung masses
and are considered malignant until proven other-
wise. 2 The prevalence of lung cancer among such
masses was more than 90% in older studies, but
there has been no recent re-evaluation. 3-4 Clinical
models and calculators described for predicting the
probability of lung cancer among SPN might not be
applicable for lung masses. 5 Nodule size is a signif-
icant predictor for malignancy, but other predictors
like margins and contours are difficult to delineate
in large lung masses spanning across different
lobes. Predictors based on computed tomography
(CT) features of large lung lesions will encourage
optimum use of non-invasive testing to comple-
ment tissue sampling and decrease the need for
multiple sampling procedures. Knowledge of
prevalence of lung cancer and benign patholo-
gies among lung masses is necessary to avoid
premature prognostication of patients with lung
masses undergoing diagnostic workup. Hence,
we investigated lung masses to determine prev-
alence of primary lung cancer and CT features
predicting a higher risk of malignancy in a retro-
spective cohort study.
MATERIALS AND METHODS
This is a single center, retrospective observa-
tional study at a tertiary care hospital. The Institu-
tional Review Board of UAMS approved this study
210 • THE JOURNAL OF THE ARKANSAS MEDICAL SOCIETY
Data collection: Detailed chart review was
performed for the selected cases with a lung
mass. Patient characteristics including age at
diagnosis, sex, and smoking status were noted.
Smoking status was classified as current smoker,
former smoker and never smoker. Former smoking
was defined as a history of smoking at least 100
cigarettes in lifetime but not at the time of diag-
nosis. 6 Thoracic CTs of all patients with lung mass
were reviewed and presence or absence of specific
features was noted. These findings were: presence
of central cavitation, central necrosis, air-bron-
chogram, well-defined borders, satellite lesions,
lymphadenopathy, pleural effusion, and if the mass
crossed anatomical boundaries.
Statistical analysis: Number of patients in
each group, namely group 1 (primary lung cancer),
group 2 (non-lung cancer malignancy) and group
3 (benign or infectious pathologies) were noted.
We conducted the analyses using proc freq and
univariate methods for categorical and numeric
variables respectively. The presence of above-
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