Odds of further surgery required depending on margins

Just had my surgery for grade 2 invasive lobular, (after a stressful almost 3 month journey but hey just glad its finally done!) - had a wide local excision / sentinal and other node removals and will get results in 4 weeks. Was surprised to learn that 1 in 5 people need further surgery due to the margins , had hoped it would be much lower odds and just wondering what anyone’s experience of this was.
Would also like to take the opportunity to praise every NHS member of staff I have encountered in past 3 months as there’s sure to be some on here, they without exception have been caring and professional and made this experience more bearable in their own way x