In modern healthcare, clinicians increasingly use instant messaging apps such as WhatsApp® to exchange information when institutional systems are slow or fragmented. DonnaRosa is an Italian community of breast cancer specialists who have used a WhatsApp® group since 2017 to discuss complex cases, share clinical opinions, and provide mutual support. This study explores how informal digital communication can develop into a professional network that complements formal infrastructures. Analysis of survey responses and group interactions shows that the community facilitates quick decision-making, continuous learning, and reassurance, especially in smaller oncology units with limited expertise. Although participant selection and gender imbalance represent potential biases, the DonnaRosa experience highlights how grassroots collaboration can strengthen clinical practice, foster professional growth, and promote resilience. These findings emphasise the enduring importance of human networks in the evolving landscape of digital communication in oncology. However, the lack of social guidelines on the professional use of instant messaging apps raises important governance and accountability concerns, emphasising the need for structured recommendations.