A total of 26,181 cases in the HIV-AIDS file were matched against all lung neoplasms diagnosed in Texas between 1990 and 1995. Matching criteria based on surname, first name, social security number, date of birth, and residence were used to identify absolute and probable matches. Probable matches were then manually reviewed to determine accurate match status.
The number of incident primary lung cancers expected among the HIV-AIDS cohort was calculated based on the US age- and sex-specific lung cancer incident rates published by the National Cancer Institute’s, Surveillance, Epidemiology, and End Results (SEER) Program. These rates were used to calculate the number of cases expected for male and for female subjects within each race/ethnicity category. These age-adjusted, race-specific expected numbers were then summed to give an overall expected number. Because sarcomas and lymphomas account for only 0.1% of the total lung neoplasm cases in the general population, expected numbers of total lung neoplasms and lung neoplasms, excluding AIDS-related sarcomas and lymphomas, were both calculated using the SEER total lung cancer incidence rate. To estimate the relative risk of primary lung cancer in the HIV-AIDS population compared with that of the US population, the ratio of observed to expected cases, or standardized incidence ratios (SIRs), were calculated. The corresponding 95% Poisson-distributed confidence levels around the SIRs also are presented.
Results
Eighty-one lung neoplasms were identified among the HIV-AIDS cohort. Sixty-eight cases (83.9%) were pathologically confirmed diagnoses. Nine cases (11.1%) were identified via death certificate information only. Seven death certificates identified primary bronchogenic carcinomas of various histologies. Two were identified as primary bronchogenic carcinomas, not otherwise specified. Five cases were diagnosed >1.5 years prior to the HIV diagnosis. In the interest of a conservative interpretation of the hypothesized biological mechanism (ie, positive HIV/AIDS status subsequently increases risk of lung neoplasms), these five cases were excluded from the study. Table 1 demonstrates the remaining 76 cases of lung neoplasms identified that constitute our study. Forty (52.6%) represented sarcomas and other soft-tissue tumors. The remaining 36 cases (47.4%) represented lung and pleural carcinomas of various histologies.

Table 1—Lung Neoplasms Identified Through Linkage of HIV-AIDS Registry and Texas Cancer Registry, Texas, 1990 to 1995

Cancer Type No. % of Total
All cancers 76 100.0
Sarcoma and other soft tissues
Kaposi’s sarcoma 22 28.9
Lymphoma 12 15.8
Reticulosarcoma 6 7.9
Total 40 52.6
Carcinomas
Squamous cell 7 9.2
Adenocarcinomas
Adenosquamous 2 2.6
Adenocarcinoma, NOS* 7 9.2
Other specified carcinomas
Small cell 3 3.9
Pseudosarcomatous 1 1.3
Merkel cell 1 1.3
Unspecified carcinomas
Large cell 3 3.9
Other 2 2.6
Other specified types
Mesothelioma 1 1.3
Unspecified 9 11.8
Total 36 47.4