Lung cancer: high death rate with HIV, huge reduction possible with CT screening for early diagnosis.

Lung cancer causes more deaths than any other kind of cancer in both men and women. It is especially fatal with HIV, in large part due to late diagnosis. Recently a major study found that in the general population, annual low-dose CT scans (formerly called CAT scans) could reduce U.S. lung-cancer deaths probably by 80% through early diagnosis. Clearly the public should note this option for doing better in saving lives.

HIV and Lung Cancer

A study of medical records at Johns Hopkins Hospital found 92 patients who had HIV and were diagnosed with lung cancer at the hospital. [1] Ninety two percent of them died of lung cancer--a 57% increase over the death rate for HIV-negative patients.

Most of the deaths were due to late diagnosis. In 32 patients in the Johns Hopkins HIV clinic, 60% of standard chest X-rays found no evidence of cancer within one year of diagnosis--compared to only 4% of chest CT scans (1 in 28 scans missed the diagnosis).

Lung-cancer patients were often young, and with their HIV disease well controlled--so doctors were unlikely to suspect lung cancer. Their median survival was only six months after diagnosis, even after the introduction of HAART.

Other studies had found that HIV patients had three to eight times the lung-cancer risk of the general population. [1]

Better Diagnosis by CT Scans

In the general population the five-year survival rate is 70% if lung cancer is caught at stage I (localized cancer), but only 5% at stage IV (distant metastases). Stage I diagnosis is unusual, mainly by lucky accident, so the overall survival rate is low.

Two months after publication of the HIV study above, the New England Journal of Medicine published results from screening over 31,000 patients annually (about two thirds of them in the U.S.) with a low-dose CT scan, using a diagnosis and treatment protocol designed for this study. [2,3] The screening diagnosed lung cancer in 484 of the participants--85% of them in stage I. For those in stage I, the estimated 10-year survival rate was 88%--92% for those who had surgery within one month of diagnosis. Eight of the patients diagnosed with stage I lung cancer did not get treatment, and all of them died within five years.

Comment

Smoking causes 87% of lung cancer, according to the American Lung Association ("Facts About Lung Cancer," November 2006), and quitting smoking lowers one's risk each year. Avoiding smoking and better diagnosis are both essential to controlling this huge cause of death.

Note that a new prescription drug, CHANTIX (varenicline), has been approved to help people quit. An editorial on this drug in the November 2006 Annals of Internal Medicine noted that even a small increase in smoking quit rates would be more important than any other medical intervention.

References

[1] Brock MV, Hooker CM, Engels EA, and others. Delayed diagnosis and elevated mortality in an urban population with HIV and lung cancer: Implications for patient care. Journal of Acquired Immune Deficiency Syndromes. September 2006; volume 43, number 1, pages 47-55.

[2] Henschke CI, Yankelevitz DF, Libby DM, and others. Survival of patients with stage I lung cancer detected on CT screening. New England Journal of Medicine. October 26, 2006; volume 355, number 17, pages 1763-1771.

[3] Unger MD. A pause, progress, and reassessment in lung cancer screening [editorial]. New England Journal of Medicine. October 26, 2006; volume 355, number 17, pages 1822-1824.