The phrase "more cankered" refers to something that is more rotten, corroded, or diseased than before. Synonyms for this could include "more decayed," "more putrid," "more deteriorated," or "more corrupted." It could also be described as "more infected," "more festering," "more ulcerated," or "more gangrenous." These words all convey a sense of something that is not only deteriorating but actively worsening. "More poisoned" or "more contaminated" could also be used, as could "more diseased" or "more blighted." Essentially, all of these synonyms capture the idea of something that is decaying or deteriorating at an accelerated rate.