Peptide receptor radionuclide therapy (PRRT) with [177Lu]Lu-DOTA-[Tyr3]octreotate has been successfully developed in the last decades for the treatment of neuroendocrine neoplasms. However, different methods to improve the objective response rate and survival are under investigation. This includes changes of the radioligand, dosimetry and combination therapy with different agents, such as radiosensitisers. Hofving et al. recently reported, in the April 2019 issue of Endocrine-Related Cancer, the use of heat-shock protein 90 (Hsp90) modulation to augment radiation effects as a new promising target for radiosensitisation. In this commentary, new developments in the field of PRRT are discussed, placing these new findings about Hsp90 inhibitors into context.
Tessa Brabander, Julie Nonnekens, and Johannes Hofland
Tessa Brabander, Wouter A van der Zwan, Jaap J M Teunissen, Boen L R Kam, Wouter W de Herder, Richard A Feelders, Eric P Krenning, and Dik J Kwekkeboom
Peptide receptor radionuclide therapy (PRRT) with [177Lu-DOTA0,Tyr3]octreotate (177Lu-DOTATATE) is a treatment with good results in patients with metastatic gastroenteropancreatic neuroendocrine tumours (GEPNETs). However, there are some pitfalls that should be taken into consideration when evaluating the treatment response after PRRT. 354 Dutch patients with GEPNETs who were treated with 177Lu-DOTATATE between March 2000 and December 2011 were retrospectively selected. Liver function parameters and chromogranin A were measured before each therapy and in follow-up. Anatomical imaging was performed before therapy and in follow-up. An increase in aminotransferases by ≥20% compared to baseline was observed in 83 of 351 patients (24%). In patients with an objective response (OR) and stable disease (SD) this increase was observed in 71/297 (24%) and in patients with progressive disease (PD) it was observed in 12/54 patients (22%). An increase in chromogranin A by ≥20% compared to baseline was observed in 76 patients (29%). This was present in 34% of patients who eventually had PD and 27% of patients who had OR/SD. In 70% of patients this tumour marker returned to baseline levels after therapy. An increase in liver enzymes and chromogranin A is not uncommon after PRRT. In the vast majority of patients this will resolve in follow-up. Clinicians should be aware that these changes may occur due to radiation-induced inflammation or disease progression and that repeated measurements over time are necessary to differentiate between the two.
Julie Refardt, Wouter T Zandee, Tessa Brabander, Richard A Feelders, Gaston J H Franssen, Leo J Hofland, Emanuel Christ, Wouter W de Herder, and Johannes Hofland
Sufficient expression of somatostatin receptor (SSTR) in well-differentiated neuroendocrine tumors (NETs) is crucial for treatment with somatostatin analogs (SSAs) and peptide receptor radionuclide therapy (PRRT) using radiolabeled SSAs. Impaired prognosis has been described for SSTR-negative NET patients; however, studies comparing matched SSTR-positive and -negative subjects who have not received PRRT are missing. This retrospective analysis of two prospectively maintained NET databases aimed to compare matched metastatic grade 1 or 2 SSTR-positive and –negative NET patients. SSTR-negativity was defined as having insufficient tumor uptake on diagnostic SSTR imaging. Patients that underwent PRRT were excluded. Seventy-seven SSTR-negative and 248 SSTR-positive grade 1–2 NET patients were included. Median overall survival rates were significantly lower for SSTR-negative compared to SSTR-positive NET patients (53 months vs 131 months; P < 0.001). To adjust for possible confounding by age, gender, grade and site of origin, 69 SSTR-negative NET patients were propensity score matched to 69 SSTR-positive NET patients. Group characteristics were similar, with the exception of SSTR-negative patients receiving more often chemotherapy and targeted treatment. The inferior survival outcome of SSTR-negative compared to SSTR-positive NET patients persisted with a median overall survival of 38 months vs 131 months (P = 0.012). This relationship upheld when correcting for the main influencing factors of having a higher grade tumor or receiving surgery in a multivariate Cox regression analysis. In conclusion, we showed that propensity score-matched SSTR-negative NET patients continue to have a worse prognosis compared to SSTR-positive NET patients despite receiving more aggressive treatment. Differences in tumor biology likely underlie this survival deficit.
Anela Blazevic, Martijn P. A. Starmans, Tessa Brabander, Roy Dwarkasingh, Renza van Gils, Johannes Hofland, Gaston J.h Franssen, Richard A Feelders, Wiro J. Niessen, Stefan Klein, and Wouter W de Herder
Metastatic mesenteric masses of small intestinal neuroendocrine tumors (SI-NETs) are known to often cause intestinal complications. The aim of this study was to identify patients at risk to develop these complications based on routinely acquired CT scans using a standardised set of clinical criteria and radiomics. Retrospectively, CT scans of SI-NET patients with a mesenteric mass were included and systematically evaluated by five clinicians. For the radiomics approach, 1081 features were extracted from segmentations of the mesenteric mass and mesentery, after which radiomics models were created using a combination of machine learning approaches. The performances were compared to a multidisciplinary tumor board (MTB). The dataset included 68 patients (32 asymptomatic, 36 symptomatic). The clinicians had AUCs between 0.62–0.85 and showed poor agreement. The best radiomics model had a mean AUC of 0.77. The MTB had a sensitivity of 0.64 and specificity of 0.68. We conclude that systematic clinical evaluation of SI-NETs to predict intestinal complications had a similar performance than an expert MTB, but poor inter-observer agreement. Radiomics showed a similar performance and is objective, and thus is a promising tool to correctly identify these patients. However, further validation is needed before transition to clinical practice.
Louis de Mestier, Angela Lamarca, Jorge Hernando, Wouter Zandee, Teresa Alonso-Gordoa, Marine Perrier, Annemieke M E Walenkamp, Bipasha Chakrabarty, Stefania Landolfi, Marie-Louise F. Van Velthuysen, Gursah Kats-Ugurlu, Alejandra Carminoa, Maxime Ronot, Prakash Manoharan, Alejandro Garcia-Alvarez, Tessa Brabander, María Isabel García Gómez-Muriel, Guillaume Cadiot, Anne Couvelard, Jaume Capdevilla, Marianne E Pavel, and Jerome Cros
There is no standardized treatment for grade 3 neuroendocrine tumors (G3 NETs). We aimed to describe the treatments received in patients with advanced G3 NETs and compare their efficacy. Patients with advanced digestive G3 NETs treated between 2010 and 2018 in seven expert centers were retrospectively studied. Pathological samples were centrally reviewed, and radiological data were locally reviewed. We analyzed RECIST-defined objective response (OR), tumor growth rate (TGR) and progression-free survival (PFS) obtained with first- (L1) or second-line (L2) treatments. We included 74 patients with advanced G3 NETs, mostly from duodenal or pancreatic origin (71.6%), with median Ki-67 of 30%. The 126 treatments (L1=74; L2=52) included alkylating-based (n=32), etoposide-platinum (n=22) or adenocarcinoma-like chemotherapy (n=20), somatostatin analogs (n=21), targeted therapies (n=22) and liver-directed therapies (n=7). Alkylating-based chemotherapy achieved the highest OR rate (37.9%) compared to other treatments (multivariable OR 4.22, 95% CI [1.5-12.2]; p=0.008). Adenocarcinoma-like and alkylating-based chemotherapies showed the highest reductions in 3-month TGR (p<0.001 and p=0.008, respectively). The longest median PFS were obtained with adenocarcinoma-like chemotherapy (16.5 months [9.0-24.0]) and targeted therapies (12.0 months [8.2-15.8]), while the shortest PFS were observed with somatostatin analogues (6.2 months [3.8-8.5]) and etoposide-platinum chemotherapy (7.2 months [5.2-9.1]). Etoposide-platinum CT achieved shorter PFS than adenocarcinoma-like (multivariable HR 3.69 [1.61-8.44], p=0.002) and alkylating-based chemotherapies (multivariable HR 1.95 [1.01-3.78], p=0.049). Overall, adenocarcinoma-like and alkylating-based chemotherapies may be the most effective treatments for patients with advanced G3 NETs regarding OR and PFS. Etoposide-platinum chemotherapy has poor efficacy in this setting.