> There is also one sure-fire way to increase telomere length : get cancer.

This badly needs a source.

This article from 2013 [1] says the opposite, that shorter telomeres are associated with cancer:

In recent years, shorter telomeres have become associated with a broad range of aging-related diseases, including many forms of cancer, stroke, vascular dementia, cardiovascular disease, obesity, osteoporosis and diabetes.

And another [2]:

"Telomere shortening is common in cancer, but the degree of shortening varies from one cancer cell to another within each patient, and this variability may give us a better idea of how prostate cancers behave."

[1]: https://www.ucsf.edu/news/2013/09/108886/lifestyle-changes-m...

[2]: http://www.hopkinsmedicine.org/news/media/releases/in_prosta...