Neuroendocrine tumours and pregnancy: Real‐world data from an European Neuroendocrine Tumour <i>Centre of Excellence</i>

Neuroendocrine neoplasms (NENs) arise from the diffuse endocrine system and have been considered to be rare. However, the incidence and prevalence of these tumours have increased in recent years, and they are being seen in younger patients including women in the reproductive age group. Due to the paucity of data, diagnostic and therapeutic strategies in managing such tumours during pregnancy can be challenging to both treating physicians and patients. This article describes the experience and outcomes of managing pregnant women with NEN at a European Neuroendocrine Tumour Society (ENETS) Centre of Excellence. In this retrospective analysis, we evaluated a total of 22 pregnancies in 18 pregnant women with concurrent diagnoses of NENs who were managed at Royal Free Hospital ENETS Centre of Excellence throughout their pregnancy. These were identified from our tumour registry of 3500 NEN patients between 2015 and 2023. Cross-sectional imaging (computed tomography (CT)/magnetic resonance imaging (MRI)), pre- and post-pregnancy, for each patient was reviewed by an experienced radiologist. Tumour growth rate (TGR) was calculated using the formula: TGR = 100 × [exp (TG) - 1]; TG. [3 × log (D2/D1)]/time (months), where D1 is the tumour size at date 1; D2 is the tumour size at date 2; and time (months) = (Date 2 - Date 1 + 1)/30.44. Tumour growth rate pre-conception (TGRpc) and tumour growth rate post-partum (TGRpp) were calculated for each patient. In a sub-group of patients, positivity for oestrogen and progesterone receptors were analysed on the tumour tissue to evaluate whether the presence of these receptors affected tumour progression during the pregnancy. We also reviewed the pregnancy outcome in patients treated with somatostatin analogues during pregnancy. We analysed the data of a total 22 pregnancy encounters in 18 women: 15 pregnancies (68%) preceded the diagnosis of the NEN, whereas the diagnosis of NEN was made during pregnancy or in the post-partum period in 5 (23%) and 2 (9%) pregnancies respectively. Eight patients (44%) had a diagnosis of a pancreatic NEN, whereas 5 (28%) were diagnosed with mid-gut NENs, and a further 5 at other sites. The majority of the patients (n = 12, 67%) had evidence of metastatic disease at the time of diagnosis. Most pregnancies had a successful outcome (n = 19, 86%), whereas 3 patients (14%) had miscarriages in the 1st trimester. Five patients in total of 6 pregnancies were treated with somatostatin analogues as monotherapy during the pregnancy, and all of them had stable disease after pregnancy. All of them delivered healthy babies without any side effects or complications due to therapy. The average TGRpc was -0.8% (n = 5) and the average TGRpp was +0.96% (n = 6); 2 patients who did not have suitable targets for calculation of TGRpc developed new lesions suggesting disease progression. Moreover, 2 of the 4 patients who have had both pre-conception and post-pregnancy scans showed an increase in TGRpp compared to TGRpc. The management of NENs during pregnancy should be multidisciplinary with an individualised approach to each patient. Somatostatin analogues appear to be safe during pregnancy, though further robust studies are needed. Pregnancy per se may accelerate tumour progression, and patients should be counselled regarding this possibility.