LUNG TUMORS

Bronchogenic carcinoma

•  Epidemiology
•  Leading cause of cancer death among both men and women
•  Increasing in women (increased smoking) in the past few decades
•  Occurs most commonly from 50-80 years of age

Major risk factors

i. Cigarette smoking

ii. Occupational exposure (asbestosis, uranium mining, radiation, etc.)

iii. Air pollution

Common genetic mutations

i. Oncogenes 

 L-myc: small cell carcinomas

 K-ras: adenocarcinomas

ii. Tumor suppressor genes p53 and the retinoblastoma gene

Clinical features

•  Cough
•  sputum production
•  weight loss
•  anorexia
•  fatigue
•  dyspnea
•  hemoptysis and
•  chest pain
•  hoarseness of voice
•  Obstruction may produce focal emphysema, atelectasis, bronchiectasis or pneumonia

Adenocarcinoma (35%)

.Males=females

.less closely associated with smoking than squamous cell

.Gross: peripheral gray-white mass with pleural puckering

.May develop in areas of parenchymal scarring (scar carcinoma)

.Micro: tumor forms glands and may produce mucin.

Bronchioloalveolar carcinoma (5%)

. Subset of adenocarcinoma

. Arises from terminal bronchioles or alveolar walls

. Gross: peripheral mucinous gray-white nodules

Micro:

     columnar tumor cells grow along the walls of pre-existing alveoli

Squamous cell carcinoma (30%)

. Males> females

. strongly related to smoking

Gross: usually centrally located, gray-white bronchial mass

            Arises from bronchial epithelium after a progression:

metaplasia ~dysplasia ~ carcinoma in situ ~ invasive carcinoma

Micro:

. Invasive nests of squamous cells

. Intercellular bridges (desmosomes)

. Keratin production ("squamous pearls")

Small cell (oat cell) carcinoma (20%)

. Males> females

. strong association with smoking

 Very aggressive: rapid growth and disseminate  early

Gross: central, gray-white masses

Micro:

small round or polygonal cells in clusters

EM: cytoplasmic dense-core neurosecretory 

granules

Commonly associated with paraneoplastic syndromes.

Also most common cause of venacaval obstruction syndromes.

Large cell carcinoma (10%)

In early stages, is associated with cavitation

Gross: peripherally located lesion

Micro: 

          large anaplastic cells without evidence of differentiation

Intrathoracic spread

i. Lymph nodes (50%):

         hilar, bronchial, tracheal, and mediastinal

ii. Pleural involvement (adenocarcinoma)

iii. Pancoast tumor (apical tumor) causing Horner syndrome

iv. Superior vena cava syndrome

     Obstruction of SVC by tumor 

     .Distended head and neck veins

     .Plethora

     .Facial and upper arm edema

v. Esophageal obstruction: dysphagia

vi. Recurrent laryngeal nerve involvement: hoarseness

vii. Phrenic nerve damage: diaphragmatic paralysis

Extrathoracic sites of metastasis:

   adrenal (>50%)

    liver

    brain and

    bone

Paraneoplastic syndromes

i. Endocrine/metabolic syndromes

    . ACTH ~ Cushing syndrome 

    . ADH~ SIADH

    . PTH ~ hypercalcemia (squamous cell carcinomas)

ii. Eaton-Lambert syndrome

iii. Acanthosis  nigricans

iv. Hypertrophic pulmonary osteoarthropathy 

. Periosteal new bone formation

. Clubbing 

. Arthritis

Investigations

Sputum cytology

Bronchoscopy:

                         Best for centrally located lesions

Fine Needle Aspiration Bx

                         for peripheral lesions

Pleural Bx in all patients presenting with pleural effusion.

CX-Ray: common features-

     a. U/L hilar lymphadenopathy

c. Lung, lobe or segmental collapse

d. Pleural effusion

b. Peripheral pulmonary opacity

c. Lung, lobe or segmental collapse

d. Pleural effusion

e. Broadening of mediastinum, enlarged cardiac shadow, elevation of hemidiaphragm.

f. Rib destruction


CT Chest

Others:
CT head
Liver ultrasound
Bone marrow biopsy

Treatment

1.Surgical resection
   Symptoms that suggest unresectable lesion: Wt. loss >10%
                                                                               

• Bone pain

other extrathoracic metastases
CNS symptoms
Tumor involving trachea, esophagus, pericardium and chest wall.

Small cell CA

2. Radiotherapy:
    palliation of distressing complications like SVC obstruction, rec. hemoptysis, pain caused by chest wall invasion.
Used in adjunct to Chemothrapy for small cell ca.
 

3. Chemotherapy

   
esp. used in small cell CA along with RT.
 
I.v Cyclophophamide, doxorubicin and vincristine
                              OR
 
I.v  Etoposide and Cisplatin are used.

4. Neoadjuvant and adjuvant CT
   CT given  surgery for down staging the disease in non small cell CA.
 Post-op CT used if lymph node is involved

5. Effusion sclerosed with tetracycline.

Prognosis:
Poorest for small cell carcinoma
Best after surgical resection of squamous cell CA.

Secondary lung tumors

Blood borne metastatic deposits from many primary tumors: part. Breast
                                                                                                         kidney
                                                                                                         uterus
                                                                                                         ovary
                                                                                                         testes
                                                                                                         thyroid
Deposits are usually multiple and bilateral.
Often there are no respiratory symptoms and diagnosis is made by radiological examination.

Malignant mesotheliomas

. Rare highly malignant neoplasm affecting the pleura.
. Occupation exposure to asbestos in 90% of cases
. Presents with recurrent pleural effusions, dyspnea, chest pain

. Gross: encases and compresses the lung

. Micro: carcinomatous and sarcomatous elements (biphasic pattern)

. EM: long, thin microvilli
.No curative treatment and chain pain is often difficult to control.
. Poor prognosis.