The incidence of lung cancer has increased amongst HIV-positive patients treated at the UK’s largest HIV clinic since the introduction of HAART, according to a study published in the 14th February 2003 edition of the journal AIDS. As previously reported on aidsmap the incidence of lung cancer and other non AIDS-defining tumours was found to be significantly increased in a large US study looking at the period before the introduction of HAART.
Investigators at the Chelsea and Westminster Hospital in London conducted a retrospective analysis of the medical records of 8,640 HIV-positive patients treated between 1986 and 2001 to see if the introduction of HAART had had an impact on the frequency with which lung cancer occured in HIV-positive patients.
Patients diagnosed with cancer before 1996 were considered to pre-HAART, those diagnosed from 1996 onwards were in the HAART era.
In total, eleven HIV-positive patients (ten gay men and one female injecting drug user) developed lung cancer over the fifteen year period of the study, two pre-HAART, the remaining nine since 1996.
Of the people diagnosed with lung cancer since HAART became available, six were diagnosed after commencing anti-HIV therapy, with the average duration of HAART being two years (range two to six years). The remaining three patients had not been treated with HAART as their immune function was well preserved.
Ten patients received anti-cancer therapy, however prognosis was poor in both the pre- and post-HAART patients, with the average progression free survival being four months for those receiving radiotherapy and five months for people treated with chemotherapy. The investigators observed that “response rates, progression free survival and overall survival were no better in the post-HAART cohort than in earlier patients.”
The incidence of lung cancer increased markedly after the introduction of HAART. Before 1996, the two cases of lung cancer represented a rate of 0.8 per 10,000 patient years, which was comparable to that seen in the general population. However, following the use of HAART the incidence rose to 6.7 per 10,000 patient-years”, significantly above that for the general population.
"The data we present here”, say the investigators, “confirm the increased incidence of lung cancer in a sizable cohort and suggest that the risk has increased since the introduction of HAART.”
Analysis of the study data revealed that the ages and CD4 counts of people developing cancer pre- and post 1996 were comparable (50 years and 100 cells mm3 pre-HAART and 44 years and 180 cells mm3 after 1996). However, the interval between HIV diagnosis and the development of lung cancer was approximately a year pre-HAART, but eleven years post-HAART.
"This is the first time that an increase in the incidence of HIV-related lung cancer has been shown when comparing a pre-HAART and post-HAART population” say the authors. They speculate that the increased incidence of lung cancers since HAART is because of “prolonged exposure to moderate immunosuppression” leading to “reduced immune function and the development of tumours.” Indeed, the type of lung cancer seen in the Chelsea and Westminster patients - adenocarcinomas - requires less genetic damage to develop than other lung tumours, and as patients live longer with HAART their chances of developing this kind of cancer increases.
The investigators conclude that “in the era of HAART, the incidence of HIV-related lung cancer has increased in our cohort, and this may be a consequence of the marked fall in opportunistic infections and AIDS defining tumours, coupled to improved life expectancy.”
Further information on this website
Bower M et al. HIV-related lung cancer in the era of highly active antiretroviral therapy. AIDS 17: 371-375, 2003.