S.S. Gordeev1, Z.N. Magarramova1,2, V.S. Myshlyakov1,2, Z.Z. Mamedli1, I.S. Stilidi1

1N.N. Blokhin National Medical Research Center of Oncology, Moscow

2A.I. Yevdokimov Moscow State University of Medicine and Dentistry, Moscow

Gordeev Sergey S. — Cand. of Sci. (Med.), leading researcher of the Oncological Department of Surgical methods of treatment №3 (coloproctology) of the N.N. Blokhin National Medical Research Center of Oncology

23 Kashirskoe highway, Moscow, 115478, Russian Federation, tel. +7-910-450-12-13, e-mail: ss.netoncology@gmail.com, ORCID ID: 0000-0002-9303-8379, SPIN-код: 6577-5540, Author ID: 841348

Abstract. Rare malignant tumors require complex diagnostics and extended multidisciplinary team discussion. Knowing rare tumours epidemiology is vital for correct organization of clinical work in different departments.

The aim of this study was to investigate epidemiological data on rare colorectal and anal malignant tumors in a large-volume tertiary hospital.

Methods. A retrospective analysis was carried out in N.N. Blokhin Russian Cancer Research Center during 2000-2020. All patients (both in- and outpatient departments) with colorectal and anal tumors were identified. Rare colorectal and anal malignant tumors were identified using an ICD-X and ICD-O codes. We investigated the incidence of identified tumors.

Results. 22 801 unique patients were identified in the registry, 15 490 (67,9%) had malignant tumors. 1443 (9,3%) had rare malignant tumors: squamous-cell cancer in 649 (45%), neuroendocrine tumors in 277 (19%), signet-cell carcinoma in 193 (13%), lymphomas in 119 (8%), melanomas in 83 (6%), sarcomas in 72 (5%), GIST in 22 (2%), other rare tumors in 22 (2%).

Conclusions. The burden of rare malignant tumors is high in clinical practice of colorectal cancer specialists. Specialized multidisciplinary teams and referral systems are necessary to improve the quality of care.

Key words: rare malignant tumors, oncoproctology, squamous-cell cancer, melanoma, sarcoma, lymphoma.