Reducing Delays in Diagnosing Lung Cancer
Because of the epidemic of suits alleging delayed diagnosis of cancer, The Doctors Company is publishing a series of diagnostic alerts to review problem areas in cancer detection. The following information pertains to lung cancer.
As with most malignancies, the presenting symptomatology of lung cancer is protean, and it ranges from subtle to dramatic in onset. Morbidity may be due to local, regional, distant, or systemic effects of the cancer. Examples include:
- Dysphagia (esophageal obstruction).
- Stridor (tracheal obstruction).
- Hoarseness (recurrent laryngeal involvement).
- Horner’s syndrome (sympathetic nerve involvement).
- Superior vena cava syndrome.
- Neurologic deficit (brain or spinal cord involvement).
- Pain or pathologic fracture (bone involvement).
- Liver dysfunction and pain.
- Paraneoplastic Syndromes
- Ectopic production of parathyroid hormone (hypercalcemia).
- Syndrome of inappropriate secretion of anti-diuretic hormone (hyponatremia).
- Myasthenic syndromes (Eaton-Lambert syndrome).
- Migratory thrombophlebitis.
- Acanthosis nigrans.
Analysis of The Doctors Company's claims experience reveals that delayed diagnosis occurs most frequently in two settings. First, the common findings listed above are often "reflexively" thought to be innocuous and are dismissed with symptomatic treatment and inadequate follow-up. Second, there is incomplete diagnostic evaluation of one of the following findings.
This problem has a particularly long and relatively esoteric differential diagnosis that requires particular attention. Because minor upper respiratory infection is by far the most common explanation, other etiologies are often overlooked. All laryngeal muscles, except the cricothyroid, are innervated by the recurrent laryngeal nerve. Injury to that nerve causes vocal cord paralysis, which can be central (10 percent) or peripheral (90 percent). Of these, fully 40 percent are due to neoplasm. Lung cancer is by far the most common (followed distantly by esophageal and thyroid tumors). Evaluating persistent hoarseness requires a chest x-ray and often mirror laryngoscopy.
Since recurrent laryngeal nerve paralysis is usually a sign of advanced lung tumor, the radiologic findings are generally obvious. Protocols for follow-up of patients given symptomatic treatment for hoarseness are mandatory.
Only 5 percent of lung cancers present as solitary pulmonary nodules, but an accurate diagnosis is especially important because virtually all cures come from this group. Overall, about one solitary pulmonary nodule in three will be malignant, but this function is strongly age dependent. Though only 1 percent are malignant in patients under age 30, this figure escalates to 50 percent in patients over age 50.
Diagnosis can be made in many ways. Bronchoscopy and needle aspiration are the most common. It is mandatory, however, that a firm diagnostic procedure is established at the outset and that a definitive conclusion is reached.
Malignancy is the cause of pleural fluid in 50 percent of patients coming to diagnostic thoracentesis. Carcinomas of the lung and breast are most commonly involved. It is extremely important that cytology be obtained, with routine studies of all unexplained pleural effusions. It will be diagnostic 30 percent to 70 percent of the time. Persistence in diagnosis is necessary and follow-up is essential.
Pulmonary infiltrates are common on chest radiograms, and only a small fraction can be attributed to malignancy. Nonetheless, many suits arise when this potential association is overlooked. Typically, pneumonitis is seen and treated empirically with antibiotics, and the patient improves clinically. Follow-up films are not obtained, and the patient goes on to manifest lung cancer in the area of the original process. Obstructive pneumonitis may clear transiently with antibiotic treatment, so it is extremely important to follow the radiograph to resolution.
Lung cancer is common in both men and women, and its presenting manifestations are protean. Delayed diagnosis usually occurs:
- When a recognized sign or symptom receives inadequate evaluation.
- When x-ray findings are missed or not followed until resolution
It is critical that all x-ray reports be initialed by the clinician before they are filed and that radiologists personally alert the referring physician when unexpected findings are present. Updated: January 1999
Originally published: April 1990