Physician Assistant Exam: Lung Cancer
Lung cancer is a leading cause of morbidity and mortality. For the Physician Assistant Exam (PANCE), be familiar with the evaluation, characteristics, and management of lung cancer. The two major types of lung cancer you need to know are small-cell lung cancer and non-small-cell lung cancer.
Lung cancer can manifest in various ways. Commonly, the affected person presents with a cough that won’t go away despite antibiotics, treatment for GERD, and treatment for asthma. Type B constitutional symptoms, including fevers, chills, and weight loss, may or may not be present. Sometimes an initial manifestation is hemoptysis. When this occurs, the pulmonologist often performs a bronchoscopy to see if an endobronchial lesion is the problem.
After diagnosis, staging is important for any type of lung cancer. Common sites of metastasis include the liver, bone, brain, and adrenal glands. CT scans of the thorax, abdomen, and pelvis as well as a bone scan should be a part of the metastasis workup. PET scanning can also be used to determine how active the cancer is.
Of course, what’s most important is to know the histologic type of cancer that you’re dealing with. Obtaining a biopsy is key.
The saying An ounce of prevention is worth a pound of cure has never been more apt than when you’re talking about lung cancer. The key is for the patient to stop smoking and avoid exposure to any type of smoke if possible.
You can have cancer in the lung that isn’t lung cancer. Many solid organ cancers, including breast cancer and renal cell cancer, can metastasize to the lung.
Small-cell lung cancer
Small-cell lung cancer is the type of cancer that, when diagnosed, you can assume has already metastasized. It’s an aggressive cancer, and it’s usually not amenable to any type of surgical intervention. The long-term prognosis isn’t good, and the treatment usually involves chemotherapy, although radiation therapy is sometimes indicated.
For PANCE purposes, realize that lung cancer, like many other solid organ cancers, is associated with paraneoplastic phenomenon. Here are some paraneoplastic phenomena associated with lung malignancies:
Ectopic ACTH secretion: The affected person can manifest all the symptoms of Cushing’s syndrome and can also have hypokalemia and a metabolic alkalosis as well as high blood pressure.
Syndrome of inappropriate antidiuretic hormone hypersecretion (SIADH): SIADH, which manifests as hyponatremia, has many causes.
Lambert-Eaton syndrome: This autoimmune phenomenon is characterized by muscular weakness affecting the legs and the arms. For test-taking purposes, be able to differentiate between Lambert-Eaton syndrome and myasthenia gravis.
The bigger picture: Non-small-cell lung cancer
Non-small-cell lung cancer (non-small-cell lung carcinoma, or NSCLC) includes a number of types of cancer:
Adenocarcinoma is the most common type of non-small-cell lung cancer. Its location is more peripheral than central. In someone who develops lung cancer but has no smoking history, you’re dealing with an adenocarcinoma more often than not.
Squamous cell cancer is the second most common type of non-small-cell lung cancer. Squamous cell cancer tends to be more central. A common paraneoplastic syndrome associated with squamous cell carcinoma is hypercalcemia. The primary treatment of squamous cell cancer is surgery, although chemotherapy and/or radiation may be needed, depending on the extent of metastasis at time of presentation.
Large-cell lung carcinoma (LCLC) accounts for 5 to 10 percent of all lung cancers. A history of smoking cigarettes increases the risk.
Bronchoalveolar cancer (BAC) is another type of non-small-cell lung cancer, but it’s a little different from its counterparts. It primarily affects women, and it’s the only lung malignancy not associated with tobacco use. Bronchoalveolar cancer isn’t felt to be an aggressive cancer, and it has a better survival rate than other forms of lung cancer.
You’re evaluating a man who says he has pain in his left arm and hand. He was newly diagnosed with lung cancer and is scheduled to go for a staging workup. Nothing has helped the pain. On exam, you notice that one pupil is smaller than the other and that his eyelid is drooping. What is your next step?
(A) Obtain a stat CT scan of the head.
(B) Obtain a stat CT scan of the chest.
(C) Obtain a neurological consultation.
(D) Order carotid Dopplers.
(E) Obtain an orthopedic consultation.
The answer is Choice (B), get a CT scan of the chest. The patient likely has a Pancoast tumor with accompanying Horner’s syndrome. A Pancoast tumor is a non-small-cell lung cancer that’s found in the apex of the lung. It can compress the brachial plexus and cause pain in the ipsilateral arm and hand.
It can also affect sympathetic nerve fibers — if they’re inhibited, the triad of Horner’s syndrome can result: miosis (constricted pupil), ptosis (sagging eyelid), and anhidrosis (lack of sweating). You’ll likely see this question in one form or another on the test.