A study of lung cancer in Johannesburg, South Africa

Abstract

We investigated whether or not differences existed between black and white patients in Johannesburg with regard to the demographic and histological features of lung cancer. This was a retrospective case record review of patients with lung cancer, seen over seven years in the pulmonology units of three hospitals attached to the University of the Witwatersrand. Seven hundred and seventy-eight black and white patients were enrolled. Six hundred and thirty-two (77.4%) of these patients were known to have smoked. The white patients were older than the black patients [median age of 66 years (range of 32-92) vs. 57 years (range of 26-86), p-value < 0.001], and had significantly greater mean pack years of smoking (52.7 ± 21.7 vs. 21.7 ± 14.3, p-value < 0.001). [Pack years is the numerical value of lifetime exposure to cigarettes, calculated as follows: the number of cigarette smoked x years of exposure/20 (a pack of cigarettes usually has 20 cigarettes)]. Histological cell types of lung cancer were squamous cell carcinoma in 341 (43.8%), adenocarcinoma in 167 (21.5%), small cell carcinoma in 129 (16.6%) and large cell carcinoma in 68 (8.7%) of the cases. More white than black patients had small cell carcinoma (p-value 0.01). More black than white patients had large cell carcinoma (p-value 0.04). There were also differences between the genders within the two racial groups. There were significant differences in the demographics and histological features when lung cancer in black versus white patients was compared. Black patients were younger and smoked fewer cigarettes. Squamous cell carcinoma was the most common cancer in all patients, except black females, in whom small cell carcinoma was more common.