Epidemiology: The most common cause of it and the deaths in the US and world wide.
Pathology:
85% are adenocarcinoma (NSCLC): most common, peripheral, non-smoker, asbestos exposure,
Large cell cancer (NSCLC): peripheral cavitation
Mesothelioma: peripheral pleural plaques, asbestos exposure. 2nd most common tumor in asbestos exposure, after adenocarcinoma.
Squamous cells cancer (NSCLC): central cavitation, PTH-rp, hypercalcemia
SCLC (oat cell ca):neuroendocrine orgin. Central. Eaton-Lambert syndrome (MG like), SIADH, SVC syndrome.
Clinical features: Cough, dyspnea, post-obstructive pneumonia, hemoptysis, CW pain. Less common symptoms are Pancoast syndrome from superiors sulcus tumors (shoulder pain, brachial plexus symptoms, and Horner’s syndrome); SVC syndrome with face and arm plethora or swelling; or voice hoarsenss from recurrent laryngeal nerve involvement. Fatigue, cachexia, bone pain, or neurologic symptoms from CNS metastasis.
Paraneoplastic syndromes include hypercalcemia (squamous cell), hyponatremia, SIADH (small-cell cancer), and hypertrophic pulmonary osteoarthropathy (clubbing, joint pain, swelling)
Dxtic Tests: Routine testing not recommended. And patient with a smoking hx and pulmonary symptoms should have the chest CT scan. Normal CXR does not exclude lung cancer. Pleural fluid cytology, bronchoscopy with Bx, brushings, or washings, or US/CT-guided needle Bx. Core needle is preferable to FNA.
Staging evaluation: In all patients, CT scan of chest and abdomen, bone scan, brain MRI (preferred), or head CT. In potentially curable patients, evaluation includes PET scan and mediastinoscopy.
Simplified TNM Staging for Lung Cancer
Risk factors:
Exposure to cigarette smoke (90%)
Exposure to asbestos, Ur, Ra, As, Ni, chloromethyl, and polcyclic aromatic hydrocarbons
Pre-existing scars of granulomatous lesion
Diffuse interstitial fibrosis
Scleroderma
Risk remains greater even 20-30 yrs after quitting smoking.
The objective is to establish that after surgical resection of the lung for a tumor, there will be sufficient pulmonary reserve to keep the patient comfortable, and will not become a respiratory cripple.
You should always evaluate the patient to determine whether he could withstand pneumonectomy even if radiologically only a lobectomy or limited resection is contemplated. On thoracotomy, a surgeon may be forced to do pneumonectomy because of an unexpected node over the pulmonary artery. If you have decided the patient cannot withstand pneumonectomy, this should be addressed with the surgeon ahead of thoracotomy.
Step 1: Routine PFTs. If the patient meets the following criteria, no further workup is necessary:
If these criteria were met and the patient were to have pneumonectomy, he would be left with at least 1 liter of FEV1 in the residual lung.
Step 2: If the patient does not meet the above criteria on routine PFT, and if the FEV1 volume is less than 2 liter, we need to perform split lung function testing. Lungs with tumor may not be contributing to total FEV1 volume and thus removal of it may not significantly affect pulmonary function. On the other hand, in some patients the diseased lung is the best lung. The best and most current method of estimating split lung function is to perform quantitative V/Q scan. Perfusion scans correlate better with pulmonary function. One can calculate the FEV1 volume of left over lung by knowing percentage of perfusion to left and right lung. For example:
Preoperative FEV1
Right Lung Perfusion
Left Lung Perfusion
1.5 liters
30%
70%
Treatment:
NSCLC:
Stage I: Surgery preferable with no further therapy; 70% chance of cure.
Stage II: Surgery followed by adjuvant chemotherapy; surgery in selected patients; <15% chance of cure.
Stage IV: Palliative chemotherapy, not curable; 40% of patients have 1-year survival
Chemotherapy: In the setting of metastases, improves survival and quality of life. Cisplatin + carboplatin and a second chemotherapy agent is standard and for patients with good performance status. Bevacizumab (an angiogenesis inhibitor) may improve survival in select patients. Erlotinib and gefitinb, oral inhibitors of EGFR TKI are effective 2nd line Tx. Lung cancers with activating mutations in the EGFR gene are highly sensitive to these inhibitors. These mutations are seen most often in never-smokers.
Small-Cell Lung Cancer
“Limited stage” (stages I to III): Chemotherapy (cisplatin + etoposide) and radiation leads to the 10-20% chance of cure.
“Extensive stage” (stage IV): Combination chemotherapy (cisplatin + etoposide or irinotecan) has a very high response rate, but all patients relapse with treatment-resistant disease. One-year survival is 30% from the time of diagnosis.
Prophylactic cranial radiation is used to select patient to prevent brain metastases.
Hypertrophic osteoarthropathy
Clubbing of digits, periosteal new bone formation and arthritis seen in intrathoracic malignancy, suppurative lung disease, congenital heart disease.
Check CXR
Check if HOA is symmetrical. If not symmetrical think about osteomyelitis.
The tumor is in the right lung. Following resection of the right lung, we can estimate 1.5 x .7 = 1.05 liters of the left lung to remain. The minimum acceptable predicted postoperative FEV1 is 800 ml. If the predicted postoperative FEV1 volume is less than 800 milliliters the patient is not a candidate for pneumonectomy.
Step 3: If the patient has predicted post-operative FEV1 value is less than 800 ml, and if the surgeon still feels that he has a resectable lesion with a good prognosis, the next evaluation would be to occlude the pulmonary artery and measure the pulmonary artery pressure at rest and with exercise. If the pulmonary artery pressure is elevated at rest or with exercise, the patient is not a candidate for pneumonectomy. The patient obviously has no capillary bed reserve and is not able to tolerate the loss of vascular bed. He will develop cor pulmonale and the expected 5 year survival will be less than 50%. This can also be done on the operating table by clamping the pulmonary artery and measuring PA