Q: Is it possible for cancer to develop as a result of an injury?
“It’s a common myth that injuries can cause cancer,” the American Cancer Society says on its website. Until the 1920s, some doctors believed trauma did cause cancer, “despite the failure of injury to cause cancer in experimental animals.”
But most medical authorities, including the cancer society and the National Cancer Institute, see no such link.
The more likely explanation, the society suggests, is that a visit to the doctor for an injury could lead to finding an existing cancer.
Other possibilities are that scar tissue from an old trauma could look like a cancerous lesion and that an injured breast or limb would be more closely watched for cancer to develop.
A single interview-based study of breast cancer in England found that 67 women with breast carcinoma were more likely to report physical trauma to the breast in the preceding five years than 134 women in a matched control group without cancer. The study was criticized because of its size and methodology.
The study, published in 2002 in the European Journal of Cancer Prevention, has not been duplicated. Its authors suggested that it was plausible that models of epithelial cell generation could be a mechanism. But the case is far from proved, even for a single type of cancer.
Q: When large deciduous trees are felled intact by storms, I’m surprised to see only a small disk of surface roots and a thin plate of soil. What happened to the root balls and deep taproots?
“The vast majority of temperate forest trees do not have taproots or even very deep roots at all,” said Melanie Sifton, vice president for horticulture at the Brooklyn Botanic Garden.
In fact, she said, for most trees, the roots are concentrated in the top foot or two of soil. The root system is more likely to expand horizontally, forming a flat, platelike mass far out beyond the tree’s canopy, or leafy zone.
Tree root systems are often categorized into three main types: plate- or surface-root systems, heart-root systems and taproot systems.
“While many temperate oak species are generally considered to have taproot systems,” Sifton said, “American elm trees, for example, are notorious for their shallow plate roots.”
Root patterns are also heavily influenced by the soil and the available underground space, she said.
To grow trees that will weather storms for many years, Sifton suggested, “give them a wide and deep space to put down roots and protect their root zones from damage and compaction.”