Bronchogenic Carcinoma & Lung Tumors

Lung Tumors

• Lung tumors were presented by Nash Denic, MD, MSci, PhD, FRCPC

Bronchogenic Carcinoma

• Occurrence of bronchogenic carcinoma is increasing.
• It is the leading cause of death globally.
• Bronchogenic carcinoma is more prevalent in males, with a 90% incidence, compared to females 75-85%.
• It generally affects individuals over 40 years of age.
• In 60% of cases, this carcinoma is incurable upon detection.
• On X-rays, a "coin lesion" has of 35-50% chance of being a carcinoma.
• Extrapulmonary symptoms like finger clubbing (hypertrophic pulmonary osteoarthropathy), Cushing's syndrome (ACTH), hypercalcemia (PTH like), hyperglycemia, encephalopathy, polymyositis, anemia, hyperpigmentation of skin could occur.
• Many tumors are associated with ectopic secretion of hormones.
  • Small Cell: ACTH, serotonin, ADH, HCG.
  • Carcinoid: ACTH, serotonin, HCG.
  • Squamous cell: parathyroid hormone (PTH).
• Bronchi can be directly extended, causing it to seed the pleura or mediastinum
• The lymphatic system can first spreads to the hilar nodes, and then the mediastinal, lower cervical, axillary, and subdiaphragmatic nodes.
• The tumor metastasizes to the liver, lungs, adrenals, bone, kidney, and CNS, particularly with adenocarcinoma.
• Staging the cancer involves examining:
  • Tis for carcinoma in situ.
  • T1a/b for tumors <3 cm.
  • T2 a/b for tumors >3 cm and <7 cm or for those involving the main bronchus or pleura.
  • T3 for tumors >7 cm or for those with direct extension into the parietal pleura, chest wall, diaphragm, or pericardium.
  • T4 when it invades the mediastinum, heart, great vessels, trachea, carina, or separate tumor nodules in the same lobe.
  • N1 for ipsilateral peribronchial or hilar nodes.
  • N2 for ipsilateral mediastinal/subcarinal lymph nodes.
  • N3 for contralateral lymph nodes or more distant lymph nodes.
  • M1 for distant metastases.
• The stage is the best predictor of the cancer's prognosis.
• Stages T1 and T2 are operable.
• Stages T3 and T4 are not operable.

Adenocarcinoma - Molecular Testing

• Epidermal Growth Factor Receptor (EGFR) is present in 10% of Western and 50% of Asian populations; TKI (thyrosin kinase receptor inhibitors) is used.
• Anaplastic Lymphoma Kinase (ALK) gene.
• PD-L1 (SqCC and AC) and ROS 1.

Bronchogenic Carcinoma - Prognosis

• 20% of cases are treated with surgery.
• A pleural effusion (T4) occurs in 1/3 of cases.
• Radiation can help; however, it is limited because in 50% of cases metastases are detected at the time of the diagnosis.
• The TNM stage is the best prognostic indicator.
• Indicators show a poor prognosis with age under 40, being female, vascular invasion, and chest wall invasion.
• A strong inflammatory response is considered a good prognostic indicator.

Squamous Cell Carcinoma

• Approximately 35-50% of cases are squamous cell carcinomas.
• This type of carcinoma is more common in males, with >80% of cases occurring in men.
• It often has a History of smoking
• They tend to be central.
• They are larger compared to the other carcinomas.
• 50% show signs of existing bronchial obstruction.
• It has a marked tendency for central necrosis and for cavitation.
• Squamous metaplasia or carcinoma in-situ is common in nearby bronchial mucosa.
• 10% present hypercalcemia caused by PTH-related protein (resulting in worse prognosis).
• It is the most curable with a five-year survival rate of 90% for early lesions, 40% for well-differentiated, 20% for moderately differentiated, and 7% for poorly differentiated cancers.

Adenocarcinoma

• Adenocarcinoma is more common in females or in males that are non-smokers with asbestos exposure.
• It is the most prevalent non-small cell lung carcinoma in the USA. It is most commonly found in the upper lobe, than the lower lobe
• Adenocarcinoma it most commonly forms in the periphery and involves the pleura.
• It is poorly circumscribed with gray-yellowish coloring.
• It it potentially associated with cancer.
• The microscopic presentation shows gland formations with non-mucin or mucin secretion.
• The main cell types are bronchial surface cells, goblet cells, Clara cells, type II alveolar cells, and mixed cell type with no mucus protection, and they often have present at resection (greater than 80%).
• EGFR mutation: 10-15%; KRAS: 20-25%.
• 5 year prognosis is ~25%.

Adenocarcinoma In Situ

• Is single or multiple nodules or diffuse pulmonic like infiltrate.
• It is <3cm with tumor cells growing along spaces
• No stromal invasion
• 5 year survival: 100%.

Small Cell Carcinoma

• Accounts for 10-15% of lung cancers
• Occurs with equal frequency among males and females
• Greater than 85% of patients are smokers.
• Location: central.
• Histology: round/oval blue cells in sheets or clusters
• Nuclei with finely dispersed chromatin (salt and pepper) with no obvious nucleoli and high mitotic rate
• EM: dense-core secretory granules
• It originates in the neuroendocrine cells in the bronchi.
• Genetic deletion is on chromosome 3p myc gene
• Prognosis: < 2% 5 year survival.
• Staging: Limited and Extensive
• Chemotherapy is used for treatment.

Large Cell Carcinoma

• Accounts for 10-15% of lung cancers
• A pleomorphic tumor with indefinite squamous or glandular differentiation
• Likely poorly differentiated variants of other tumor types

Other Carcinomas

• Include adenosquamous carcinoma and carcinomas with pleomorphic, sarcomatoid or sarcomatous elements, such as pulmonary blastoma (embryoma), carcinosarcoma, giant cell carcinoma, and/or spindle cell carcinoma

Other Tumors

• Include carcinoid tumors
  • Less than 5% of tumors
  • Younger age (<40 years)
  • No association with smoking
  • Central are the most common.
  • Peripheral.
  • Atypical.

Central Carcinoid Tumor

• It is most common and accounts for 85% of tumors.
• It’s growth is slow, it is solitary, endobronchial, forms a polypoid gray-yellow mass with high vascularity.
• Histology: small,uniform cells with central nuclei growing in compact nests
• EM: dense core granules.
• Metastasis to regional lymph nodes occur in 5% of cases and distant metastases rarely occur.
• 10 year survival rate is 70-80%.

Other Tumors

• Include hamartoma (chondroid hamartoma)
  • They are benign; accidental findings
  • Adults
  • Beneath pleura
  • Made up of islands of cartilage, fat, smooth muscle and respiratory system
  • Are easily resectable

Other Tumors

• Include salivary Gland-Type Tumors, lymphomas and metastases

Tumors of the Pleura - Mesothelioma

• Two thirds are related to asbestos exposure
• Chronic asbestos exposure 2-3% risk
• Risk is not increased with smoking
• Amphiboles (esp. crocidolite) is the most carcinogenic material
• Has a long latency between exposure and tumor : 25-45 yr.
• More commonly asbestos bodies are in the lung
• There are multiple gray-white, ill-defined nodules, diffusely thickening of pleura, may fill pleura space and encase lung
• Chemotherapy for treatment
• Survival rate is 50% 1 year.