The role of tissue diagnosis prior to neoadjuvant chemoradiotherapy for locally advanced rectal cancer.

Abstract

Neoadjuvant chemoradiotherapy is the standard of care for locally advanced rectal cancer, with diagnostic work-up routinely including a biopsy confirming invasive carcinoma. For the occasional patient where initial biopsies reveal only dysplasia, or even normal epithelium, repeat biopsy is currently advised, but this may delay therapy and repeat biopsy has potential adverse effects. The study aimed to determine, in the setting of clinical findings and imaging demonstrating locally advanced rectal cancer, whether the absence of a tissue diagnosis prior to commencing chemoradiation compromises patient outcome. A review was conducted of our database, including comprehensive treatment and outcome details, in which consecutive patients with colorectal cancer have been enrolled since 1997 at a single institution. All records for patients who received neoadjuvant chemoradiotherapy for locally advanced rectal cancer were reviewed to identify patients for whom treatment was initiated before a tissue diagnosis was obtained, and to assess any consequences of this. Of 254 patients who had received neoadjuvant treatment for rectal cancer, 16 (6.3%) were found to have had neoadjuvant therapy without a tissue diagnosis of invasive cancer. Compared with cases where a tissue diagnosis had been obtained, median age (59 vs 63 years, P = 0.497), sex (75% vs 71.3% male, P = 0.955) and tumour location (56.3% vs 73.5% < 8 cm, P = 0.230) were similar. Of these, 14 (87.5%) had adenocarcinoma identified on histopathology review of the surgical specimen. Three patients were considered to have had complete pathological responses with mucin lakes within the muscularis propria (n = 2) or lymph nodes (n = 1) or fibrosis (n = 3). One of these had no mucin evident and only fibrosis; thus final pathological proof of invasive cancer was present in 15 (93.5%) patients. There were no local recurrences, but three of the 16 (18.8%) cases developed distant recurrence. For the small number of cases without a confirmatory tissue diagnosis before chemoradiation, no adverse consequences were identified. In particular the initial diagnosis was confirmed in 15 out of 16 cases following pathological examination of the operative specimen. We would suggest that, where clinical and radiological features support a diagnosis of locally advanced rectal cancer, proceeding directly to neoadjuvant chemoradiotherapy in the absence of a biopsy demonstrating invasive cancer may not be unreasonable, particularly where repeat biopsy would delay the commencement of treatment.