Still struggling with the word pre-cancer after DCIS mastectomy

hmmm...can't say too much but I overheard a conversation between a surgeon and a reg not too long ago.  They were discussing calling a lady back for better margins on a dcis lumpectomy case. Surgeon wanted the person back sooner rather than later.  Reg questioned surgeon regarding the urgency (during covid when non urgent cases were put on hold).  The answer came back as "never underestimate DCIS.  It is not to be trusted... ever" 
All the best lovely.  xoxoxo