Type:
Educational Exhibit
Keywords:
Pathology, Neoplasia, Diagnostic procedure, CT, Thorax, Oncology
Authors:
M. Gutiérrez Gimeno1, N. Baixeras1, M. Arzanauskaite2; 1Barcelona/ES, 2Liverpool/UK
DOI:
10.1594/ecr2018/C-2904
Background
In 2012 lung cancer was responsible for 1,6million deaths worldwide.
It represents a leading cause of disease as the most common cancer in men and third most common cancer in women [1],
(fig.
1).
Traditionally it has been classified depending on their appearance in optical microscopy. Four main histological types can be distinguished (fig.
2):
- Adenocarcinoma (40%)
- Squamous cell carcinoma (25-30%)
- Large cell carcinoma (15%)
- Small cell carcinoma (~15%)
In 2011 a new lung adenocarcinoma classification was released by a multidisciplinary joint commission of the American Thoracic Society (ATS) and European Respiratory Society (ERS) [2],
(fig.
3).
Of many changes,
the two most relevant were:
- The terms bronchioloalveolar carcinoma and adenocarcinoma mixed subtype were abandoned and replaced by more histologically accurate categories.
- The stress on the importance of molecular features and their prognostic implications.
By that time,
a consistent correlation between CT findings and histologic abnormalities within the spectrum of peripheral lung adenocarcinoma was already known [3],
but it was not definitely standardised until the publication of the ATS/ERS classification.
The changes introduced were rapidly adopted by the radiological community [4,5].
In 2017,
new Fleischner Society guidelines incorporated the latest evidence regarding the risk of malignancy and management of ground glass and part solid nodules [6].
Part-solid nodules are those including a combination of ground-glass and solid components.
Both,
pure ground-glass nodules and part-solid nodules are considered subsolid [5].
Nevertheless,
despite the efforts to early diagnose,
a great majority of neoplasms is diagnosed in an advanced stage (large solid masses,
nodal or distant dissemination) [7].
In such cases,
molecular analysis acquires the greatest importance because of the availability of new selective drugs driven against specific cancerous signalling pathways. Since its first appearance more than ten years ago,
targeted therapy has radically changed the therapeutic approach to non-small cell lung cancer,
and particularly adenocarcinoma [8].