The new method, based on automatic understanding is proposed for fighting spam in web information exchange (especially email correspondence). The web cancer term is used to reflect the variety and sophistication of web contaminations. The notable oncology achievements in medicine could inspire more research towards finding solutions to what can easily turn into an analogous civilization crisis. Automatic understanding is appropriate for the semantic-level content analysis and is expected to substantially reduce the wasted user time for semi-automatic analysis needed for the massive processing as most filters are too tight or too loose.