Pathology

Scottish Cancer Network: Clinical Management Pathways
NHS National Services Scotland
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This consensus document is not a rigid constraint on clinical practice, but a concept of good practice against which the needs of the individual patient should be considered. It therefore remains the responsibility of the individual clinician to interpret the application of these guidelines, taking into account local service constraints and the needs and wishes of the patient. It is not intended that these consensus documents are applied as rigid clinical protocols.  This clinical management pathway is a summary of the Royal College of Pathologists Dataset for histopathological reporting of lung cancer1.  Readers are directed to this document for detailed guidance.

Clinical information required on specimen request form

  • Demographics – Name / Date of Birth / CHI number
  • Specimen type (s) and detail of procedure
  • Previous biopsy/cytology results, previous malignancy / oncological treatments
  • Other relevant past medical history

Small biopsies

Particular care should be placed on the handling of small biopsy specimens due to the increased requirement for tissue preservation to ensure sufficient material is available for molecular testing.

Suggested practice

  • Process cores in separate blocks
  • Avoid overuse of immunohistochemistry (IHC) / deeper levels
  • If morphological features of adenocarcinoma or squamous cell carcinoma present then diagnostic IHC is not required unless there is a question regarding the primary site
  • If appearances are of non-small cell lung cancer (NSCLC) without features of adenocarcinoma or squamous cell carcinoma then limited panel of IHC advised (TTF1/Napsin A and p40/p63/CK5/6 (one of each is sufficient)).
  • Histopathological diagnosis of individual entities should be based on the WHO classification2

Surgical resection specimens

Use of a reporting proforma is strongly encouraged in the reporting of lung surgical resection specimens including wedge resection, segmentectomy, lobectomy and pneumonectomy.  See RCPath Dataset1 and Appendix 1 for suggested templates. 

Final tumour staging should be conducted using the UICC TNM8 classification.

Core pathology data items are1:

  • Location of tumour
  • Size of tumour (mm)
  • Distance from bronchial resection margin
  • Atelectasis
  • Histological type (including histological patterns of adenocarcinoma)
  • Local invasion
    • Pleura
    • Pericardium, heart, diaphragm, chest wall and great vessels
    • Presence of malignant effusions
  • Separate tumour nodules: satellite nodules (intrapulmonary metastases) versus synchronous primary tumours
  • Metastatic deposits
  • Resections following therapy
  • Lymph node spread
    • pN1 - involved ipsilateral hilar/peribronchial or intrapulmonary nodes,
    • pN2 - involved ipsilateral mediastinal or subcarinal nodes,
    • pN3 - involved contralateral mediastinal, contralateral hilar, ipsilateral or contralateral scalene or supraclavicular nodes
    • Include comment on extracapsular extension at margins of resected nodes
  • Margin status

Although not a core dataset item the description of lymphovascular invasion is advisable as it is an independent prognostic risk factor. 

Molecular testing

Routine molecular testing in non-squamous non-small cell lung cancer (particularly adenocarcinoma and NSCLC-NOS) includes:

  • EGFR (epidermal growth factor receptor),
  • KRAS (Kirsten rat sarcoma virus),
  • Alk (Anaplastic Lymphoma Kinase),
  • ROS1,
  • PD-L1 (programmed death-ligand 1)

In squamous cell carcinoma only PD-L1 testing is required.

Appropriate molecular testing should be requested on all patients with Stage III and IV disease as well as those surgical resections with a final classification of Stage Ib and above.  

Reflex testing irrespective of the clinical stage is advisable for all new diagnoses of NSCLC but should be agreed upon following discussion with local molecular pathology services.

References

  1. G048 Dataset for the histopathological reporting of lung cancer, RCPath 2018
  2. WHO Classification of Tumours Editorial Board. Thoracic Tumours. 5th ed. International Agency for Research on Cancer, Lyon, France 2021
  3. Brierley J, Gospodarowicz MK, Wittekind C. TNM classification of malignant tumours. Wiley, Chichester 2017

Appendix 1 - Lung Proforma

Editorial Information

Last reviewed: 20/09/2023

Next review date: 20/09/2026

Author(s): David Dorward on behalf of the Lung Pathology Subgroup.

Version: 1

Reviewer name(s): John Maclay.