Lung Cancer, Primary

• • Typically spread by local extension, metastasis to lymph nodes, lung, liver, bone, brain, adrenals

Non-Small-Cell Lung Carcinoma (NSCLC)

• • 80% of cases

  • Classified as:

  • -Early without mediastinal involvement (stage I/II)

    -Locally advanced (stage IIIA/B)

    -Metastatic (stage IV)

Squamous Cell Carcinoma

• • 20% of cases

  • Keratinization, cellular stratification, and intercellular bridges seen pathologically

  • 67% located centrally, 33% located peripherally

  • Growth and metastasis rate slower than other lung tumors

  • Classified into 2 groups:

  • 1. Disease in ipsilateral thorax (including lymph nodes)

    2. Disease beyond thorax (extensive)

Adenocarcinoma

• • 30% of cases

  • 3 subtypes

  • -Acinar (columnar lined glands secreting mucin)

    -Papillary

    -Bronchoalveolar (intraluminal papillary fragments in alveoli)

  • Increasing frequency, may be spread by aerosol transmission

Large Cell Carcinoma

• • Uncommon

  • Large polygonal spindle/oval cells in sheets or nests

  • Tumors seen peripherally

Small Cell (Oat Cell) Carcinoma

• • 15% of cases

  • Small round nuclei with nuclear chromatin and cytoplasm

  • Biologically and clinically distinct from others

  • Occur centrally, early metastasis, highly resistant to treatment

Adenosquamous Tumors

• • Show both cellular features

  • More aggressive than NSCLC

Epidemiology

• • Number 1 cause of cancer-death in men and women

  • 170,000 new cases each year: 157,000 deaths each year

  • Incidence stable among males, increasing among females

  • 85% of cases due to smoking tobacco

  • Asbestos exposure implicated in 23% of lung cancer cases, radon increases risk

  • Occurs more frequently in right lobe than in left

  • Upper lobes affected more than lower or middle lobes

  • Increased risk to develop other cancers:

  • -Upper respiratory tract

    -Esophagus

    -Bladder

    -Kidney

  • No survival benefit from mass screening

Symptoms and Signs

• • Central tumors: Cough, hemoptysis, respiratory distress, pain, pneumonia

  • Peripheral tumors: Cough, chest wall pain, pleural effusions, pulmonary abscess, Horner syndrome, Pancoast syndrome

  • Symptoms from regional spread: Hoarseness (recurrent nerve paralysis), dyspnea (phrenic nerve paralysis), dysphagia (esophageal compression), tamponade (pericardial invasion)

  • Systemic symptoms: Anorexia, weight loss, weakness, malaise

  • Classic paraneoplastic syndromes:

  • -Small cell: Eaton-Lambert (myasthenia), SIADH, ACTH, carcinoid

    -SCC: Hypercalcemia

    -Adenocarcinoma: acanthosis nigricans

Laboratory Findings

• • Elevated alkaline phosphatase suggests bony metastases

Imaging Findings

• • Chest film: Vary from nodule to unresolving infiltrate to total atelectasis

  • Chest CT scan: Evaluation of infiltrate, nodule

• • Definitive diagnosis obtained in 90% with bronchoscopy or fine-needle aspiration (FNA)

Rule Out

• • Metastatic disease with imaging (see below) and thoracentesis

• • Chest film often done for routing physical or for symptoms

  • CT chest/abdomen: to rule out common sites of metastasis, such as liver and adrenals

  • If serum alkaline ...