Clinical outcomes of adolescent and young adult patients (AYAp) vs mature adult patients (MATp) with colorectal cancer (CRC), a multi-institutional retrospective review

Background: On contrast to the general population, incidence of CRC in AYA is on the rise. However, very little is understood about the clinical patterns and outcomes of CRC in AYAp, especially when compared to MATp. A retrospective data review was performed to further understand the aforementioned.

Materials and Methods: A multi-institutional retrospective review was performed by four tertiary institutions. AYAp [18–44 years old (yo)] and MATp (>44yo) diagnosed with CRC from June 2003-June 2014 were retrieved. Cox proportional hazards models to estimate crude and adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) of overall survival (OS), progression-free survival 1 (PFS 1; time from 1st-line treatment to progression or death), and PFS 2 (time from 2nd-line treatment to progression or death), comparing AYAp with MATp. Models conditioned on center, adjusted for sex, primary tumor location, metastasis at diagnosis, T (T of TNM) and year of diagnosis.

^aPer 100 Person-years.

Results: Total of 229 patients with CRC, AYAp 132 [median age 37.7 yo (24–44), male 54.6%, median follow up 24.3 months (1.7–91.1)] and 97 MATp [median age 61.7 yo (45–89), male 57.7%, medial follow up 19.9 months (1.2–81.4)] were identified. At diagnosis 63.4% AYAp presented with metastatic disease and primary CRC location were 40.9% left, 18.2% right, 37.1% unknown. Mutation analysis of AYAp showed: no mutations of KRAS 58/78 (74.4%), NRAS 9/11 (81.8%), and BRAF 9/12 (75%) patients. Total 104 AYAp received 1st-line chemotherapy for metastatic CRC: CAPOX/FOLFOX n=80, CAPIRI/FOLFIRI n=10, FLOX n=5, FOLFIRINOX n=3 with concurrent bevacizumab n=63, cetuximab n=7, panitumumab n=3. Total of 81 (61.3%) underwent surgical intervention throughout their course of treatment. Hazard ratios showed no association between age group and OS, PFS 2 as it demonstrated adjusted HR of 1.26 (95%CI: 0.70–2.26) and 1.19 (95%CI:0.66–2.15) respectively. However, association was seen in PFS 1 with adjusted of HR 2.00 (95%CI: 1.22–3.28). (Table 1)

Conclusion: Both AYAp and MATp had similar OS, in line with published literature. However, association between age groups in PFS 1 may illustrate more aggressive nature of CRC in AYAp subgroup. Further collaboration analyzing AYAp with CRC is required to better elucidate treatment patterns and outcomes.

No conflict of interest.