Cough! Is it Cancer?

The Key to Treatment of Cancer-Related Cough Is Identifying its Underlying Cause

Coughs can be horribly intrusive. Many coughs are associated with known causes, and all indicate a problem in or near the pulmonary system.¹ Coughs’ acute physiologic function is protective—it clears the upper tracheobronchial tree of mucus and foreign bodies.² Dry cough can accompany the common cold, or it can be an early sign of bronchitis (inflamed bronchi) or laryngitis. Whooping cough is a dry and quite distinctive cough. Asthmatics frequently bark out a dry cough when exposed to irritants.³

And then there’s productive cough. Colds often cause wet, phlegmy coughs, as does chronic bronchitis. Productive coughs also result from bacterial infection, pulmonary edema, use of an intermittent positive-pressure breathing machine, cystic fibrosis, and gastroesophageal reflux. The prototypical productive cough is that associated with tuberculosis; it’s an explosive, ragged, guttural sound of air being forced through fluid.³

Chronic cough of either type is physiologically maladaptive: it no longer serves its original purpose. For example, smokers often develop throat-clearing habits—habits to which they are oblivious but which others find annoying—that can progress to a chronic dry hacking. After a respiratory infection clears, a dry cough often lingers as pulmonary tissues heal. Chronic cough is exhausting and annoying. It can cause shortness of breath, incontinence, and sleeplessness for the patient and the patient’s bed partner or entire household. At its worst, it can cause rib fracture.^2,3 Clearly, coughs can be serious enough to cause patients to worry. Often, that worry is that they may have cancer.³

When Does a Cough Signal Cancer?

In oncology, coughs are generally associated with upper or lower respiratory tract cancers, or metastases from cancers in other areas to the lungs. A recent study found that among 973 cancer patients referred to palliative care and having any type of cancer, 36% experienced cancer-elated cough. For 90% of those patients, the cough was severe.⁴ Approximately 65% of people diagnosed with lung cancer have a chronic cough at diagnosis, and it’s often the reason prompting the visit to a physician.¹

Cancer coughs have no specific pattern. They may occur during the day only, or continue through the night, interfering with sleep and causing daytime fatigue. Many patients who develop respiratory tract cancers are current or former smokers who have smoker’s cough. If they develop cancer, their cough may be the same as it’s always been, or it may have a different character, perhaps harsher or more nagging. Table 1^1,5 describes coughs that are more likely to be associated with cancer.

Coughs related to respiratory cancers may irritate the lungs or windpipe, producing either dry or productive coughs. Numerous other causes can contribute to or aggravate cough in the cancer patient (Table 2⁵). Sometimes the cough produces mucus, blood, or tissue. Many cancer symptoms are interrelated, occurring in clusters because they have common or interactive mechanisms. In cancer patients, cough often occurs with other aerodigestive symptoms, including dysphagia, dyspnea, hoarseness, and wheezing.^4,6

Management

Clinicians generally ask about cough’s intensity and quality; its temporal onset, frequency, and course; precipitating, aggravating, and alleviating factors; and accompanying symptoms. They sometimes remember to ask about cough’s contribution to the patient’s (and the family’s) emotional stress. Cough is much like pain in that only the patient’s assessment matters. If cough is painful, intrusive, or emotionally distressful to patients, clinicians need to help patients manage it.⁵

The primary treatment for cancer-related cough is treatment of the underlying disease or reversible causes. Usually, this includes chemotherapy with or without radiation or surgery.^2,7 Pharmacists should remember that some chemotherapy, especially bleomycin and methotrexate, can induce cough, as can angiotensin-converting enzyme inhibitors, midazolam, and nonsteroidal anti-inflammatory drugs.⁷ Patients who have infection, clots, or asthma need antibiotics, anticoagulants, and corticosteroids, respectively.

Little research about cough has been conducted in patients with advanced disease. Nonpharmacologic interventions often help relieve cough or reduce its frequency or severity (Table 3^3,5,7).

Resorting to Medication

Most pharmacologic interventions for cancer-related cough are based on observation or past success, not evidence from clinical trials. Patients who have highly productive cough may find that expectorants make mucus less viscous and easier to dislodge. Nebulized saline solution can reduce respiratory tract irritation. Dehydration is a common problem in cancer patients and can aggravate cough; correcting it with increased hydration is a simple step.⁵

Peripheral and central antitussants suppress the cough reflex. Although studies have demonstrated that opioids do not suppress cough in patients who are cancer-free,⁸ they seem to work in cancer patients. Hydrocodone is usually the first opioid used.^5,7,9 Benzonatate has been studied in cancer and advanced cancer cough, and found to be effective.^7,10 Dextromethorphan is also worth a try because it is effective in many patients and has low toxicity.¹¹ Products that contain lidocaine, a peripherally active antitussant, can also soothe cough.⁵ A case report indicates that diazepam may help when patients have intractable cough.¹²

Endnote

Moderate to severe cough is a common problem in cancer patients. Often, clinicians ignore patients’ coughing until the patient or family complains. Evidence-based recommendations are needed for cancer-related cough. Until studies provide that evidence, pharmacists can recommend several interventions that may help relieve the cough, reduce associated discomfort, and improve emotional well-being.

Ms. Wick is a Visiting Professor at the University of Connecticut School of Pharmacy and a former National Cancer Institute employee.

References

1. Kvale PA. Chronic cough due to lung tumors: ACCP evidence-based clinical practice guidelines. Chest. 2006;129(suppl):47-53.

2. Wee B, Browning J, Adams A, et al. Management of chronic cough in patients receiving palliative care: review of evidence and recommendations by a task group of the Association for Palliative Medicine of Great Britain and Ireland. Palliat Med. 2012;26:780-787.

3. Myers J. Physiology and pathophysiology of cough. In: Ahmedzai SH, Muers MF, eds. Supportive care in respiratory disease. Oxford: Oxford University Press; 2005:341-364.

4. Aktas A, Walsh D, Hu B. Cancer symptom clusters: an exploratory analysis of eight statistical techniques. J Pain Symptom Manage. Published online April 18, 2014.

5. Bausewein C, Simon ST. Shortness of breath and cough in patients in palliative care. Dtsch Arztebl Int. 2013;110:563-571.

6. Kirkova J, Aktas A, Walsh D, Davis MP. Cancer symptom clusters: Clinical and research methodology. J Palliat Med. 2011;14:1149-1166.

7. Homsi J, Walsh D, Nelson KA. Important drugs for cough in advanced cancer. Support Care Cancer. 2001;9:565-574.

8. Schroeder K, Fahey T. Over-the-counter medications for acute cough in children and adults in ambulatory settings. Cochrane Database Syst Rev. 2004;(4):CD001831.

9. Morice AH, Menon MS, Mulrennan SA, et al. Opiate therapy in chronic cough. Am J Respir Crit Care Med. 2007;15:312-315.

10. Doona M, Walsh D. Benzonatate for opioid-resistant cough in advanced cancer. Palliat Med. 1998;12:55-58.

11. Matthys H, Bleicher B, Bleicher U. Dextromethorphan and codeine: objective assessment of antitussive activity in patients with chronic cough. J Int Med Res. 1983;11:92-100.

12. Estfan B, Walsh D. The cough from hell: diazepam for intractable cough in a patient with renal cell carcinoma. J Pain Symptom Manage. 2008;36:553-558.