mFOLFOX6 Chemotherapy after Resection of Anal Canal Mucinous Adenocarcinoma

Perianal Mucinous Adenocarcinoma: A Case Report and a Systematic Review of the Literature

BACKGROUND

Mucinous adenocarcinoma of anus is an uncommon neoplasm of the gastrointestinal tract. In most of the cases, early diagnosis of this disease is difficult since its symptoms frequently mimic benign inflammatory conditions.

METHODS

A systematic PubMed and Scopus search was conducted, a propos of a case report.

RESULTS

One hundred fifty patients from 93 case reports were included. The mean age of the patients was 60.5 years (range: 18-81). The majority of them were males (124 out of 150, 82.7%), while the main known risk factor was the history of chronic fistula (109 out of 150, 72.7%). Recurrent perianal sepsis and perianal pain were the principal symptoms at the time of presentation. No symptoms have been reported only in three patients (3 out of 150, 2%). Regarding the prior surgical history of the patients, multiple abscess drainage and perianal fistula's related interventions were present in 62 (41.3%) and 19 (12.7%) patients, respectively. Neoadjuvant chemoradiotherapy was administered in 53 out of 150 patients (35.3%), while the majority of them have been treated with combined treatment of chemotherapy and radiotherapy. APR and its variations were the most applied surgical treatment (68%). Adjuvant chemoradiotherapy was administered almost up to one-third of the included patients (34%). Recurrence of the disease was reported in 41 out of 150 patients (27.3%). Death was reported in 44 out of 150 patients (29.3%).

CONCLUSION

Review of the available published literature suggests that perianal mucinous adenocarcinoma is an extremely rare neoplasia. Τhere is no consensus as far as the diagnosis and the treatment strategies, due to the rarity of this neoplasm. High degree of clinical suspicion as well as histopathological confirmation is the principal requisites for the diagnosis of mucinous adenocarcinoma, especially in the ground of chronic ulcero-proliferative perianal lesions.

A dualistic model of primary anal canal adenocarcinoma with distinct cellular origins, etiologies, inflammatory microenvironments and mutational signatures: implications for personalised medicine

Background

Primary adenocarcinoma of the anal canal is a rare and aggressive gastrointestinal disease with unclear pathogenesis. Because of its rarity, no clear clinical practice guideline has been defined and a targeted therapeutic armamentarium has yet to be developed. The present article aimed at addressing this information gap by in-depth characterising the anal glandular neoplasms at the histologic, immunologic, genomic and epidemiologic levels.

Methods

In this multi-institutional study, we first examined the histological features displayed by each collected tumour (n = 74) and analysed their etiological relationship with human papillomavirus (HPV) infection. The intratumoural immune cell subsets (CD4, CD8, Foxp3), the expression of immune checkpoints (PD-1, PD-L1), the defect in mismatch repair proteins and the mutation analysis of multiple clinically relevant genes in the gastrointestinal cancer setting were also determined. Finally, the prognostic significance of each clinicopathological variable was assessed.

Results

Phenotypic analysis revealed two region-specific subtypes of anal canal adenocarcinoma. The significant differences in the HPV status, density of tumour-infiltrating lymphocytes, expression of immune checkpoints and mutational profile of several targetable genes further supported the separation of these latter neoplasms into two distinct entities. Importantly, anal gland/transitional-type cancers, which poorly respond to standard treatments, displayed less mutations in downstream effectors of the EGFR signalling pathway (i.e., KRAS and NRAS) and demonstrated a significantly higher expression of the immune inhibitory ligand-receptor pair PD-1/PD-L1 compared to their counterparts arising from the colorectal mucosa.

Conclusions

Taken together, the findings reported in the present article reveal, for the first time, that glandular neoplasms of the anal canal arise by HPV-dependent or independent pathways. These etiological differences leads to both individual immune profiles and mutational landscapes that can be targeted for therapeutic benefits.