Saturday, January 23, 2010
January 22nd - MHH - Lung Cancer
On the boards, the info you'll need to know for Lung Cancer is broad, so here is a quick review. I would be familiar with staging - although the boards will not likely ask you to stage, they may ask a questions regarding treatment modality. To know this, you need to know the stage.
Risk Factors: Smoking (increases risk about 15x normal. Even 2nd hand smoke exposure increases risk about 2x), asbestos exposure, other heavy metal exposure
Clinical Presentation: Over 90% of patients with a diagnosis of lung cancer have some sort of symptoms - either from local involvement, paraneoplastic syndromes or metastatic disease. Local symptoms depend on the location of the lesion. So the more "central" cancers (i.e. small cell and squamous cell) present with bronchial obstruction, pneumonia, cough, hemoptysis and dyspnea. The more "peripheral" cancers can present with pleurisy, chest wall pain and pleural effusion. Obviously either can cause dyspnea as well as cough/hemoptysis, and there is some overlap. Think of lung cancer in a patient with a history of COPD that presents with an "exacerbation" that is different than their usual exacerbation (i.e. more severe, or lasting longer). Also consider with new onset COPD symptoms in an older patient. Other signs/symptoms include change in voice, Horner's Syndrome, arm paresthesias, SVC syndrome, clubbing, temporal wasting and lymph node enlargement. Metastatic disease can present with bony pain, headache/AMS, or hepatomegaly. We'll go over paraneoplastic syndromes in a bit as well.
Diagnosis: CXR for initial suspicion, followed by CT Scan. You ideally want to biopsy any lymph nodes first, but can also biopsy the mass. Bronchoscopy can be used for central lesions that are >4cm. Open biopsy or IR-guided biopsy if the lesion is peripheral or small.
Classification/Pathology and Subtypes:
Non-Small Cell Subtypes (includes squamous cell, large cell and adenocarcinoma)
Others: carcinoid and rare pathology (carcinoid is reviewed in one of my earlier posts)
Small Cell Carcinoma
Usually metastasize early, as compared to the non-small cell types. Located more "central" Paraneoplastic syndromes include SIADH, Eaton-Lambert and ectopic ACTH production.
Staging for Small Cell:
Limited: Can fit within one radiation therapy Port (Confined to one Lymph Node, the Mediastinum and A Supraclavicular LN)
Extended: If it does not fit into one port
Treatment for Small Cell:
Limited: Cisplatin + Etoposide with Radiation
Extensive: Cisplatin + Etoposide or Carboplatin + Etoposide
If Brain Metastases are Present - Radiation and Steroids (Some give prophylactic cranial irradiation for both stages, although it is more controversial for Limited-Stage Disease)
Non-Small Cell Subtypes:
Squamous Cell - Most likely to cavitate. Central Lesion. Hypercalcemia
Large Cell - Peripheral. Mets to CNS
Adenocarcinoma - Peripheral. Seen 50% of the time in non-smokers. Bronchoalveolar carcinoma is a subtype of adenocarcinoma that looks like pulmonary edema/diffuse interstitial infiltrates
Staging for Non-Small Cell:
Stage I: <3cm and no LAD or Mets
Stage II: Hilar LAD or Chest Wall
Stage III: Mediastinal LAD
Stage IV: Mets
Further Workup for Non-Small Cell:
Mediastinoscopy for LN >1cm
CT and MRI of Head usually needed
Bone Scan if symptoms of bone pain or increased Alk Phos
Treatment for Non-Small Cell:
Stage I and II: Sx and Chemo (Debate if radiation is added to this – it may increase mortality).
Stage III: Chemo and Radiotherapy
Stage IV: Chemo for patients with good Performance status
Chemotherapy for Non-Small Cell usually consists of:
Adenocarcinoma: Oral Gefitinib used at times
Here is a chart I made comparing "high-yield" basics for the 4 types:
Paraneoplastic syndromes - the boards like these, so know them cold!
SIADH - Hyponatremia (what are the labs with SIADH? UNa>50 and Uosm>200) - Small Cell
Hypercalcemia and it's multiple symptoms - usually squamous cell
Acromegaly - GH secretion usually from small cell subtype
Cushing's Syndrome - ACTH secretion from small cell subtype
Hypertrophic Pulmonary Osteoarthropathy - New periosteal bone formation - usually adenocarcinoma
Lambert Eaton Syndrome - Proximal Muscle Weakness, autonomic dysfunction (impotence and dry mouth) with areflexia and sparing cranial nerves The amplitude of action potentials on EMG, and symptoms, improve with repetitive stimulation. This usually occurs with Small Cell Subtypes. (Remember that Myasthenia has cranial nerve involvement, normal reflexes, and worsening with repeated motion)