Pathologic Assessment of Rectal Carcinoma after Neoadjuvant Radio(chemo)therapy: Prognostic Implications

Abstract

Neoadjuvant radio(chemo)therapy is increasingly used in rectal cancer and induces a number of morphologic changes that affect prognostication after curative surgery, thereby creating new challenges for surgical pathologists, particularly in evaluating morphologic changes and tumour response to preoperative treatment. Surgical pathologists play an important role in determining the many facets of rectal carcinoma patient care after neoadjuvant treatment. These range from proper handling of macroscopic specimens to accurate microscopic evaluation of pathological features associated with patients' prognosis. This review presents the well-established pathological prognostic indicators and discusses challenging features in order to provide both surgical pathologists and treating physicians with a checklist that is useful in a neoadjuvant setting.

Transanal total mesorectal excision (taTME) for rectal cancer: a systematic review and meta-analysis of oncological and perioperative outcomes compared with laparoscopic total mesorectal excision

“…For example, the patients in the taTME group of the study by Perdawood et al [ 26 ] showed a obviously higher BMI when compared with those in the laTME group ( P = 0.07), the patients in the study of Hevia et al [ 28 ] showed a difference in age between the two groups ( P = 0.06), and the distance of tumor the above the anal verge showed a significant difference between groups in Chen’s study ( P = 0.02) [ 30 ]. Importantly, neoadjuvant treatments may be a potential confounding factor for the oncological outcomes of rectal cancer [ 48 ]. However, we could not conduct a subgroup analysis based on whether patients had received neoadjuvant treatments before surgical resection by all the possible means.…”

Placement of a self-expandable metallic stent as a bridge to surgery for large bowel obstruction induced by effective neoadjuvant therapy: report of three cases

“…LBO with growth of fibrous and edematous tissue can occur as an adverse event during NAT. Neoadjuvant chemoradiotherapy for rectal cancer causes tumor regression by eradication and replacement of carcinoma cells by fibrous or fibroinflammatory tissues [ 8 ]. Previous studies have shown that patients with fibroinflammatory changes after neoadjuvant chemoradiotherapy have better disease-free survival [ 9 , 10 ].…”

Is There a Role for Programmed Death Ligand-1 Testing and Immunotherapy in Colorectal Cancer With Microsatellite Instability? Part I—Colorectal Cancer: Microsatellite Instability, Testing, and Clinical Implications

“…affect IHC staining, especially for MSH6, which may be absent, weak, or stain just the nucleoli. 33,34 In these cases, pretreatment biopsy, if available, may be more suitable for MSI testing. 4.…”