Evolution of clinical nature, treatment and survival of locally recurrent rectal cancer:Comparative analysis of two national cross-sectional cohorts

Background: In the Netherlands, use of neoadjuvant radiotherapy for rectal cancer declined after guideline revision in 2014. This decline is thought to affect the clinical nature and treatability of locally recurrent rectal cancer (LRRC). Therefore, this study compared two national cross-sectional cohorts before and after the guideline revision with the aim to determine the changes in treatment and survival of LRRC patients over time. Methods: Patients who underwent resection of primary rectal cancer in 2011 (n = 2094) and 2016 (n = 2855) from two nationwide cohorts with a 4-year follow up were included. Main outcomes included time to LRRC, synchronous metastases at time of LRRC diagnosis, intention of treatment and 2-year overall survival after LRRC. Results: Use of neoadjuvant (chemo)radiotherapy for the primary tumour decreased from 88.5% to 60.0% from 2011 to 2016. The 3-year LRRC rate was not significantly different with 5.1% in 2011 (n = 114, median time to LRRC 16 months) and 6.3% in 2016 (n = 202, median time to LRRC 16 months). Synchronous metastasis rate did not significantly differ (27.2% vs 33.7%, p = 0.257). Treatment intent of the LRRC shifted towards more curative treatment (30.4% vs. 47.0%, p = 0.009). In the curatively treated group, two-year overall survival after LRRC diagnoses increased from 47.5% to 78.7% (p = 0.013). Conclusion: Primary rectal cancer patients in 2016 were treated less often with neoadjuvant (chemo)radiotherapy, while LRRC rates remained similar. Those who developed LRRC were more often candidate for curative intent treatment compared to the 2011 cohort, and survival after curative intent treatment also improved substantially.