Selective use of radiation for locally advanced rectal cancer: one size does not fit all.

The last three decades have seen several major advances in the multidisciplinary management of locally advanced rectal cancer (LARC). Although rectal cancer management varies globally, the standard of care for clinical stage II/III rectal cancer in North America remains chemoradiation followed by total mesorectal excision and adjuvant therapy. In this review we evaluate the evidence for neoadjuvant therapy in LARC and the variety of treatment options available. We identify heterogeneity of outcomes in stage II/III rectal cancer, leading to the potential for overtreatment. The PROSPECT Trial is a multicenter, international effort to determine whether a selective approach to provision of radiotherapy in stage II/III LARC is a viable treatment option. Unlike many other studies, the aim of PROSPECT is to reduce treatment rather than increase the intensity of preoperative therapy. LARC is a heterogeneous disease with varying risk of relapse. Studies are underway to attempt to individualize care to avoid overtreatment while maintaining excellent oncologic outcomes.