Oncological outcome after lateral pelvic lymphadenectomy for low rectal carcinoma: not only an N-status matter

Tumour deposits (TDs), novel pathological entities, should be considered when estimating the regional and systemic spread of rectal carcinoma and formulating treatment strategies. In fact, TDs may have more severe prognostic impact than lymph node positivity or the lymph node ratio. The assessment of the presence of TDs can be performed only through accurate postoperative pathological examination; however, the detection of TDs is not part of any of the procedures currently used to assess preoperative or intraoperative staging. This review aims to analyse and discuss the impact of TDs on the oncological outcome of patients who undergo surgery for advanced low rectal carcinoma. No prospective study has evaluated the impact of lateral pelvic TDs on oncological outcomes following total mesorectal excision with lateral pelvic lymphadenectomy. Although adequate total mesorectal excision allows for the excision of intramesorectal TDs, lateral pelvic lymph node dissection cannot guarantee the removal of lateral pelvic TDs; moreover, it remains to be determined whether surgical excision of lateral pelvic TDs can impact long-term outcomes. However, the identification of lateral pelvic TDs strengthens the 'staging effect' and limits the 'therapeutic effect' of lateral pelvic lymphadenectomy, supporting the rationale for the use of neoadjuvant chemoradiotherapy for rectal cancer. When evaluating the oncological outcomes after total mesorectal excision with lateral pelvic lymphadenectomy, the impact of lateral pelvic TDs should be considered.