Watch and wait after a clinical complete response in rectal cancer patients younger than 50 years

Background: Young-onset rectal cancer, in patients less than 50 years, is expected to increase in the coming years. A watch-and-wait strategy is nowadays increasingly practised in patients with a clinical complete response (cCR) after neoadjuvant treatment. Nevertheless, there may be reluctance to offer organ preservation treatment to young patients owing to a potentially higher oncological risk. This study compared patients aged less than 50 years with those aged 50 years or more to identify possible differences in oncological outcomes of watch and wait. Methods: The study analysed data from patients with a cCR after neoadjuvant therapy in whom surgery was omitted, registered in the retrospective-prospective, multicentre International Watch & Wait Database (IWWD). Results: In the IWWD, 1552 patients met the inclusion criteria, of whom 199 (12.8 per cent) were aged less than 50 years. Patients younger than 50 years had a higher T category of disease at diagnosis (P = 0.011). The disease-specific survival rate at 3 years was 98 (95 per cent c.i. 93 to 99) per cent in this group, compared with 97 (95 to 98) per cent in patients aged over 50 years (hazard ratio (HR) 1.67, 95 per cent c.i. 0.76 to 3.64; P = 0.199). The cumulative probability of local regrowth at 3 years was 24 (95 per cent c.i. 18 to 31) per cent in patients less than 50 years and 26 (23 to 29) per cent among those aged 50 years or more (HR 1.09, 0.79 to 1.49; P = 0.603). Both groups had a cumulative probability of distant metastases of 10 per cent at 3 years (HR 1.00, 0.62 to 1.62; P = 0.998). Conclusion: There is no additional oncological risk in young patients compared with their older counterparts when following a watch-and-wait strategy after a cCR. In light of a shared decision-making process, watch and wait should be also be discussed with young patients who have a cCR after neoadjuvant treatment.