Residency Program - Case of the Month

Answer:

Poorly differentiated squamous cell carcinoma of lung primary

Discussion:

In the United States, lung cancer is the second most common cancer, after prostate cancer in men. The American Cancer Society projected that 224,210 cancers of the lung and bronchus would be diagnosed in the United States in 2014, with 159,260 deaths.¹

Squamous cell carcinoma accounts for 25-30% of all lung cancers. It is the type most often associated with hypercalcemia which the decedent displayed prior to his death. The decedent had a history of extensive smoking. The development of lung cancer is directly related to number of cigarettes smoked, length of smoking history, and the tar and nicotine content of the cigarettes. Risk is highest among current smokers and lowest among nonsmokers. A large trial showed that persistent smokers had a 16-fold elevated lung cancer risk, which was further doubled in those who started smoking when younger than 16 years.²  The age-adjusted incidence rates range from 4.8-20.8 per 100,000 among nonsmokers to 140-362 per 100,000 among active smokers.

In addition to smoking, the decedent had a history of asbestos exposure. The silicate type of asbestos fiber is an important carcinogen. Asbestos exposure has been shown to be strongly associated with the causation of lung cancer. Asbestos exposure increases the risk of developing lung cancer by as much as 5 times.

Tobacco smoke and asbestos exposure act synergistically, and the risk of developing lung cancer for persons who currently smoke tobacco and have a history of asbestos exposure approaches 80-90 times that of control populations.³

Lung cancer is highly lethal. US data collected from 2004-2010 indicate that the 5-year relative survival rate for lung cancer was 16.8%. However, the 5-year relative survival rate varies markedly, depending on how advanced the disease is at diagnosis.⁴

Metastatic bone tumors occur at particularly high rates in cancers of the breast, prostate, lung, and kidney, accounting for 75% of all patients⁵. Many patients with lung cancer are in advanced stages of the disease at the time of diagnosis.

Although it is reported bone metastasis from lung cancer occurs in 14% to 40% of patients, its clinical features have not been clearly described⁵. The cause of death was primarily due to the decedent’s metastatic poorly differentiated squamous cell carcinoma.

Resources:

1.  American Cancer Society. Cancer Facts & Figures 2014. American Cancer Society. Available at http://www.cancer.org/acs/groups/content/@research/documents/webcontent/acspc-042151.pdf.

2.  Ginsberg RJ, Vokes EE, Raben A. Non-small cell lung cancer. DeVita VT Jr, Hellman S, Rosenberg SA, eds. Cancer: Principles and Practice of Oncology. 5th ed. Philadelphia, Pa: Lippincott-Raven; 1997:858-911.

3.  Agaku IT, King BA, Dube SR. Current cigarette smoking among adults in United States, 2005-2012. MMWR Morb Mortal Wkly Rep. Jan 17 2014;63(2):29-34.

4.  D'Addario G, Fr h M, Reck M, Baumann P, Klepetko W, Felip E. Metastatic non-small-cell lung cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann Oncol. May 2010;21 Suppl5:v116-9.

5.  Tofe AJ, Francis MD, Harvey WJ. Correlation of neoplasms with incidence and localization of skeletal metastases: an analysis of 1,355 diphosphonate bone scans. J Nucl Med. 1975;16:986 989.