Total neoadjuvant therapy standard therapy of locally advanced rectal cancer with high-risk factors for failure.

Background: For locally advanced rectal cancer (LARC), standard therapy [consisting of neoadjuvant chemoradiotherapy (CRT), surgery, and adjuvant chemotherapy (ChT)] achieves excellent local control. Unfortunately, survival is still poor due to distant metastases, which remains the leading cause of death among these patients. In recent years, the concept of total neoadjuvant treatment (TNT) has been developed, whereby all systemic ChT-mainly affecting micrometastases-is applied prior to surgery.

Aim: To compare standard therapy and total neoadjuvant therapy for LARC patients with high-risk factors for failure.

Methods: In a retrospective study, we compared LARC patients with high-risk factors for failure who were treated with standard therapy or with TNT. High-risk for failure was defined according to the presence of at least one of the following factors: T4 stage; N2 stage; positive mesorectal fascia; extramural vascular invasion; positive lateral lymph node. TNT consisted of 12 wk of induction ChT with capecitabine and oxaliplatin or folinic acid, fluorouracil and oxaliplatin, CRT with capecitabine, and 6-8 wk of consolidation ChT with capecitabine and oxaliplatin or folinic acid, fluorouracil and oxaliplatin prior to surgery. The primary endpoint was pathological complete response (pCR). In total, 72 patients treated with standard therapy and 89 patients treated with TNT were included in the analysis.

Results: Compared to standard therapy, TNT showed a higher proportion of pCR (23% 7%; = 0.01), a lower neoadjuvant rectal score (median: 8.43 14.98; < 0.05), higher T-and N-downstaging (70% and 94% 51% and 86%), equivalent R0 resection (95% 93%), shorter time to stoma closure (mean: 20 33 wk; < 0.05), higher compliance during systemic ChT (completed all cycles 87% 76%; < 0.05), lower proportion of acute toxicity grade ≥ 3 during ChT (3% 14%, < 0.05), and equivalent acute toxicity and compliance during CRT and in the postoperative period. The pCR rate in patients treated with TNT was significantly higher in patients irradiated with intensity-modulated radiotherapy/volumetric-modulated arc radiotherapy than with 3D conformal radiotherapy (32% 9%; < 0.05).

Conclusion: Compared to standard therapy, TNT provides better outcome for LARC patients with high-risk factors for failure, in terms of pCR and neoadjuvant rectal score.