Mineral dusts in lungs with scar or scar cancer

Abstract

Five lungs with small scars and five lungs with small scar associated cancers, were studied by light and scanning electron microscopy and x‐ray energy dispersive spectrometry. Six hundred particles were photographed and their physical and chemical properties analyzed from scar, cancer, or normal alveolar tissue on carbon planchet‐mounted, deparaffinized and low temperature‐ashed sections. Amosite/crocidolite fibers were accumulated only in one cancerous lung. All other lungs shared similar types of mineral particles. The lungs with noncancer scars, however, showed an increase in the ratio of aluminum and calcium salts (non‐silicates), while the lungs with scar cances had a higher ratio of silicates. These patterns of particle distribution were similar in different areas of the same lung, despite the fact that particles accumulated heavily in the scar and scarcely in the normal alveolus. Although the mechanism is unclear, these results are consistent with the possibility that the pattern of mineral particle distribution in a lung may influence the formation of cancer in a scar.

Inflammation as Cause for Scar Cancers of the Lung

“…By using clinical data (tissue pathology/histology), which are obtained long after the events leading to the scar or cancer formation have occurred, it is often difficult to sort out any definitive time sequence between the initiation of the processes resulting in scar formation and the subsequent development of the tumor. In spite of these limitations, in some reports there is evidence that the scar (and scarring process) predates the tumor, [6][7][8][9][10][11] in others it is impossible to tell, 12,13 and in others there is evidence that there was an active scarring process as a result of the tumor. 2,3,5,[14][15][16] The basic assumption behind any conclusions of no association between a pulmonary scar and its "associated" tumor [1][2][3][4][5] is that the scar itself cannot have directly caused the tumor.…”

“…In more general terms, it may be no coincidence that either a variety of pulmonary infections or mineral deposits in the lungs were regarded as the most likely damaging agents leading to inflammation and scar formation in those reports that had evidence that scar formation predated the lung cancers. [6][7][8][9]11 Inflammatory processes in response to those agents (leading to scarring) could very likely have been one of the predominant mechanistic causes of the lung cancers as well.…”

“…The purpose of this review is to illustrate from a mechanistic standpoint that inflammatory processes may be very important risk factors for pulmonary cancers, with scar cancers of the lung being a relatively highincidence example of this risk. Although scar cancers of the lung have been recognized for several decades, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] a direct mechanistic association between the scar itself and the tumor has not been documented. Because no direct evidence has been observed for a causal association between the presence of scar tissue and cancer, several relatively recent publications have refuted the concept that pulmonary scars can be causal in lung cancer.…”