Baseline and early digital [18F]FDG PET/CT and multiparametric MRI contain promising features to predict response to neoadjuvant therapy in locally advanced rectal cancer patients: a pilot study

Objective In this pilot study, we investigated the feasibility of response prediction using digital [18F]FDG PET/computed tomography (CT) and multiparametric MRI before, during, and after neoadjuvant chemoradiation therapy in locally advanced rectal cancer (LARC) patients and aimed to select the most promising imaging modalities and timepoints for further investigation in a larger trial.Methods Rectal cancer patients scheduled to undergo neoadjuvant chemoradiation therapy were prospectively included in this trial, and underwent multiparametric MRI and [18F]FDG PET/CT before, 2 weeks into, and 6–8 weeks after chemoradiation therapy. Two groups were created based on pathological tumor regression grade, that is, good responders (TRG1-2) and poor responders (TRG3-5). Using binary logistic regression analysis with a cutoff value of P ≤ 0.2, promising predictive features for response were selected.Results Nineteen patients were included. Of these, 5 were good responders, and 14 were poor responders. Patient characteristics of these groups were similar at baseline. Fifty-seven features were extracted, of which 13 were found to be promising predictors of response. Baseline [T2: volume, diffusion-weighted imaging (DWI): apparent diffusion coefficient (ADC) mean, DWI: difference entropy], early response (T2: volume change, DWI: ADC mean change) and end-of-treatment presurgical evaluation MRI (T2: gray level nonuniformity, DWI: inverse difference normalized, DWI: gray level nonuniformity normalized), as well as baseline (metabolic tumor volume, total lesion glycolysis) and early response PET/CT (Δ maximum standardized uptake value, Δ peak standardized uptake value corrected for lean body mass), were promising features.Conclusion Both multiparametric MRI and [18F]FDG PET/CT contain promising imaging features to predict response to neoadjuvant chemoradiotherapy in LARC patients. A future larger trial should investigate baseline, early response, and end-of-treatment presurgical evaluation MRI and baseline and early response PET/CT.</div

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.Surgical oncolog

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

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.Data from the International Watch and Wait Database have been analysed. There is no additional oncological risk in patients younger than 50 years compared with their older counterparts when following watch and wait after the achievement of a clinical complete response following neoadjuvant treatment for rectal cancer.Surgical oncolog