PURPOSE: To correlate regional incidence rates of a series of malignant tumors with those of bronchogenic lung cancers, as a surrogate marker, to assess the role of smoking as a causative factor in malignancies.
METHODS: Cigarette smoking is a well established causative risk factor for bronchogenic lung cancer. Smoking has also been linked to a variety of other solid tumors. We hypothesized that regions having particular incidence rates for lung cancer should correlate with respective incidence rates of other solid tumors if smoking is a causative risk factor for both tumor types. Alternatively, malignant tumors not having smoking as a significant causative risk factor should not correlate. Regionally based incidence rates from the SEER database for lung cancer and a variety of other malignancies were stratified and graphed. Statistical regression analyses were performed to assess correlations.
RESULTS: Cancers that are well accepted as having smoking as a causative risk factor showed statistically significant correlation with lung cancer when respective incidence rates were plotted. The analysis confirms the linkage of smoking to cancers of the larynx and urinary bladder. Malignant tumors whose graphs show scatter and no correlation are those with weak or no association with smoking as a risk factor, such as leukemia and brain cancer. The variance of the correlation corresponds to the impact of smoking as a causative risk factor for carcinoma.
CONCLUSION: Regionally based incidence rates for lung cancer act as a surrogate marker for smoking and show a significant correlation with other smoking related cancers. Cancers of unknown association may be assessed for correlation with lung cancer to determine the impact of smoking as a risk factor.
CLINICAL IMPLICATIONS: The model of regionally based comparative incidence rates may be applicable as a surrogate marker to assess the risk factor association of smoking or other causative agents in the development of malignant tumors.
DISCLOSURE: Arnold Schwartz, No Financial Disclosure Information; No Product/Research Disclosure Information