ESTRO 2024 - Abstract Book

S1482

Clinical - Lower GI

ESTRO 2024

18,729 and 12,649 patients from England and NK were identified. Demographics of patients in the two cohorts were similar: Age ≤70yrs versus >70yrs (England 61.8%:38.2%, NK 59.6%:40.4%); sex male versus female (England 63.6%:36.4, NK 66.0%:35.0%); worse clinical or pathological stage I/II versus III (England 35.5%:64.5%, NK 40.4%:58.1%) and types of surgery APR versus anterior resection versus other (England 68.6%:30.7%:0.7%, NK 60.61%:24.17%:15.22%). However the use of neoadjvuant (chemo)radiotherapy differed significantly (England 36.3% versus NK 75.7%). In both countries, LCRT was preferred over SCRT, although this preference was stronger in England (75% LCRT vs 54% in NK). As expected, the use of adjuvant chemotherapy was much more common in England (34.4%) compared to NK (3.6%), with a different spread of chemotherapy regimens used in the two cohorts. The 5-yr observed survival (OS) was significantly better for patients receiving adjuvant chemotherapy compared to those who did not in England (70.9% (95% CI 70.0-71.7) to 77.8% (95% CI 76.6-78.9)), (Figure 1). However there was no survival difference between the same cohorts in NK (74.2% (95% CI 73.4-75.0) to 77.8% (95% CI (73.7-81.3)). The improvement in OS in the English cohort is significant in the cohort of patients who did not receive neoadjvuant LCRT (71.4 (95% CI 70.4-72.4) to 79.8 (95% CI 78.5-81.1)) compared to a minimal benefit for those who did receive LCRT (69.3 (95% CI 67.6-71.0) to 72.8 (95% CI 70.5-74.9) ) (Figure 2).

Conclusion:

This real world data analysis has confirmed a marked difference in use of adjuvant chemotherapy for rectal cancer between England and the Netherlands. The significant survival advantage from using adjuvant chemotherapy in the English cohort suggests that it is useful for selected patients, likely for those not receiving neo-adjuvant LCRT.