Treatment patterns in metastatic early-onset rectal cancer.

Background: Early onset rectal cancer (EORC) is increasing internationally. While EORC cancer presents with some distinct clinical features, there is currently insufficient evidence that age of onset should alter treatment. This study examines treatment patterns for EO versus late-onset (LO) metastatic rectal cancer in Canterbury, New Zealand, to better understand appropriate treatment strategies and there effect on patient outcomes.

Methods: A retrospective study on all patients diagnosed with stage 4 rectal adenocarcinoma in Canterbury from 2010 to 2021 was undertaken. Patients under 50 were compared to a control group aged 60-74, analysing treatment patterns, hospital stays, and survival outcomes.

Results: Between 2010 and 2021, there were 949 rectal cancer diagnoses in Canterbury, of which 23 were EO and 64 were LO with stage 4 cancer. Survival analysis revealed a significant difference in median survival times between EORC (47.9 months) and LORC patients (26.5 months; P = 0.03). There was no significant difference in the surgical or oncological management between age groups (P > 0.05). Mean admissions per 100 days of life was 0.45 in LORC and 0.44 in EORC (P = 0.9119). There was no significant difference in the median proportion of time spent in hospital between EO and LO groups (2.5 vs. 2.2 days for every 100 days of life, P = 0.88).

Conclusion: Surgical and oncological treatments were similar for both EORC and LORC groups. The EO group exhibited better survival, with hospitalization burdens comparable for both. These findings underline the importance of maintaining an approach to metastatic RC balancing survival and quality of life.