The incidence, treatment and survival of patients with rare types of rectal malignancies in the Netherlands: A population-based study between 1989 and 2018

Jan M Van Rees,Marloes A.G Elferink,Pieter J Tanis,Johannes H.W De Wilt,Jacobus W.A Burger,Cornelis Verhoef

doi:10.1016/j.ejca.2021.04.036

Abstract

AimTo describe the incidence, treatment and survival of patients with rare types of rectal malignancies in the Netherlands. MethodsData of patients with rectal malignancies diagnosed in the Netherlands between 1989 and 2018 were retrieved from the Netherlands Cancer Registry and grouped according to the RARECARE cancer list. Age-standardised incidence rates were calculated using the European Standard Rate. The Joinpoint Regression Program was used for analysing trends and joinpoints and for the estimation of annual percentage changes (APCs). Patient characteristics, treatment details and relative survival (RS) were reported for different histological types of rectal malignancies and compared between different time periods. RS was assessed using Kaplan-Meier analysis and log-rank test. ResultsA total of 88,299 cases of rectal malignancies were included of which 2125 (2.5%) were categorised as rare histological subtypes. The incidence of rectal neuro-endocrine tumours (NET) (APC: 6.2%, 95% confidence interval [CI]: 5.4%; 7.1%), rectal sarcoma (APC: 5.8%, 95% CI: 2.9%; 8.7%) and rectal adenocarcinoma (APC 1.0%, 95% CI: 0.26%; 1.8%) increased. Prognosis was best in patients with rectal NET (5-year RS: 72.4%, 95% CI: 70.1%; 74.7%) and worst in patients with rectal melanoma (5-year RS: 8.9%, 95% CI: 5.1%; 15.7%). RS has improved in patients with rectal adenocarcinoma, rectal sarcoma and rectal lymphoma in 2008–2018 (p-values p < 0.001, p = 0.023 and p = 0.029). ConclusionSignificant increases in incidence were observed for different types of rectal malignancies. Differences in incidence, treatment and survival found in this study could be useful to make clinicians aware of specific diseases.

Highlights

Significant increases in incidence rates were found for rectal neuro-endocrine tumours (NET) (APC: 6.2%, 95% confidence interval (CI): 5.4%; 7.1%), rectal sarcoma (APC: 5.8%, 95% CI: 2.9%; 8.7%) and rectal adenocarcinoma (APC 1.0%, 95% CI: 0.26%; 1.8%)
The incidence rates of the five rare rectal cancers combined increased with 5.1% per year
Rectal sarcoma and rectal lymphoma diagnosed in 2008e2018 had significantly better survival compared to patients diagnosed in 1989e2007 (Fig. 3). In this population-based study including patients diagnosed with different histological subtypes of rectal malignancies between 1989 and 2018 in the Netherlands, rare types of rectal tumours accounted for about 2.5% of all cases, which is comparable with studies reporting the incidence of rare colorectal cancers [21,22]

Summary

Introduction

Adenocarcinoma is the most common histological type of rectal cancer and accounts for more than 90% of all cases [1,2]. The remaining, less common types of rectal malignancies include neuro-endocrine tumours (NET), sarcoma, lymphoma, melanoma and squamous cell carcinomas (SCC). No studies describing the incidence of multiple histological subtypes of rectal malignancies have been conducted. Population-based data of rare types of rectal malignancies are scarce and are mainly limited to one specific entity [3e6]. A nationwide bowel cancer screening programme was implemented in 2014, which likely has changed the incidence since [8,9]. Whether there have been changes in the incidence of the rare types of rectal malignancies and the impact of the bowel screening program is yet unknown

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