The Case Volume Issue in Head and Neck Oncology.

In the past few years, several evidences reported better outcomes, in terms of reduced toxicities and longer survival, for head and neck cancer (HNC) patients when "regionalized," namely if they are managed at "high-volume" cancer referral centers (CRC). The benefit of case volume has been demonstrated in HNC patients primarily treated with surgery and in those receiving curative radiotherapy and chemotherapy. Many factors could explain these positive results: organization, facilities, processes of care, quality assurance programs, professional expertise, technology, and patient referral bias. In other words, the "high volume" could be linked both to all hospital-related volume and to the expertise of each involved professional figure (e.g., surgeon, radiation oncologist, medical oncologist, etc.). In this context, it is still debatable whether there is a need to understand which one of these factors is more able to influence the final outcomes of HNC patients. Considering the complexity and heterogeneity of HNC, all of these aspects are likely to impact and plot each other. However, there is no consensus regarding the criteria and the cut-off used to define as "high" the case volume. Moreover, some limitations or biases of the regionalization process have to be highlighted: (1) personal and financial discomfort of patients, their caregivers, and families; (2) a frequent referral of the healthiest or youngest patients to CRC could change the survival outcomes; (3) potential higher difficulties for colleagues working outside of CRC in the emergency. Nevertheless, the case volume represents one of the factors impacting on the quality of the treatment itself, in terms of reduced toxicity and better treatment outcome. Therefore, it should be considered as a stratifying factor in randomized controlled trials for HNC patients.