Sign in

Thor Halfdanarson

@oncothor.bsky.social
1K followers 426 following 138 posts

🇮🇸 🇺🇸 Medical Oncologist/Educator, NET/GI/CUP enthusiast. Husband/dad x4 (bad dad jokes). Cyclist. Avant gardener. Professor of Oncology, Mayo Clinic. Tweets mine, not endorsement/advice. tinyurl.com/22w4kxjj #NETsSky #MedSky #OncSky

PostsRepliesMedia
Thor Halfdanarson @oncothor.bsky.social · 10/04/2026
More on germline mutations in patients with NETs 453 patients with NETs, 11.5% with a germline pathogenic or likely pathogenic variant, most commonly in MEN1 (3.5%). Other alterations noted were PALB2, SDHB, BRIP1 and MUTYH. A nice addition to the lit. onlinelibrary.wiley.com/doi/full/10....
onlinelibrary.wiley.com
Germline Mutation Landscape of Neuroendocrine Tumors in the Chinese Population
Hereditary syndromes account for roughly 5 to 10 percent of neuroendocrine tumors (NETs). However, most studies of germline mutations in NET have involved Caucasian populations. This retrospective st...
000
Thor Halfdanarson @oncothor.bsky.social · 09/04/2026
Rage, rage against the dying of the light… False spring #6 this year in Rochester. How was your commute home from work…?
000
Thor Halfdanarson @oncothor.bsky.social · 16/07/2025
Are you an oncologist with interest in GI cancer? If so, are you interested in joining a growing academic GI Oncology practice in Rochester, MN? We have 13 GI oncs with additional 3 joining soon and still growing 😀 We are hiring! PM me if interested. jobs.mayoclinic.org/job/rocheste...
jobs.mayoclinic.org
Life-Changing Careers at Mayo Clinic
Learn more about applying for Gastrointestinal Medical Oncologist at Mayo Clinic
010
Thor Halfdanarson @oncothor.bsky.social · 16/07/2025
Adjuvant immunotherapy (camrelizumab) and CRT following resection of gall bladder cancer and extrahepatic cholangiocarcinoma. Small randomized trial, interesting findings in need of further validation. jamanetwork.com/journals/jam...
jamanetwork.com
Adjuvant Chemoradiation and Immunotherapy for Extrahepatic Cholangiocarcinoma and Gallbladder Cancer
This randomized clinical trial evaluates the safety and efficacy of immunotherapy combining with chemoradiotherapy.
010
Thor Halfdanarson @oncothor.bsky.social · 09/06/2025
Want a quick update in medical oncology on July 19 (with some heme updates in the mix)...? If so, we have the course for you! I can promise excellent content/speakers and there is a livestream (virtual) option too for those who cannot attend in person. ce.mayo.edu/hematology-a...
021
Thor Halfdanarson @oncothor.bsky.social · 04/06/2025
The next frontier in radioligand therapy (RLT), radioligand-antibody drug conjugates...? Interesting data targeting TROP2 and HER2 in xenograft mouse models with orthotopic breast tumors. I am certainly keeping an eye on how this develops... aacrjournals.org/mct/article/...
aacrjournals.org
177Lu-Labeled Antibody–Drug Conjugate: A Dual-Mechanistic Treatment Modality in Solid Tumors
Abstract. To explore the potential of site-selectively radiolabeled antibody–drug conjugates (ADC) against solid tumors, we constructed and evaluated radiolabeled ADCs equipped with lutetium-177 (177L...
010
Thor Halfdanarson @oncothor.bsky.social · 03/06/2025
PRRT is a very effective for well-differentiated NETs but associated with a low risk of treatment related myeloid neoplasms ( t-MN ). If you are interested in learning more, this is the review for you... erc.bioscientifica.com/view/journal...
erc.bioscientifica.com
020
Thor Halfdanarson @oncothor.bsky.social · 19/05/2025
Lot to unpack from the excellent NORDIC NEC2. - ORR: 31% for NEC (mostly plat/eto) - this is NOT SCLC - ORR: 27% for G3 NETs (mostly TMZ-based) - Immediate progression: 41% of NECs, 21% G3 NETs - PFS: 3.4 m NEC; 7.4 G3 NET NECs are really bad cancers! www.nature.com/articles/s41...
nature.com
Characteristics and treatment outcome in a prospective cohort of 639 advanced high-grade digestive neuroendocrine neoplasms (NET G3 and NEC). The NORDIC NEC 2 study - British Journal of Cancer
British Journal of Cancer - Characteristics and treatment outcome in a prospective cohort of 639 advanced high-grade digestive neuroendocrine neoplasms (NET G3 and NEC). The NORDIC NEC 2 study
011
Thor Halfdanarson @oncothor.bsky.social · 14/05/2025
Did you just wake up thinking how great it wold be to have a new review on extrahepatic cholangiocarcinoma...? If so, you are in luck. Here it is, courtesy of EASL www.sciencedirect.com/science/arti...
sciencedirect.com
EASL Clinical Practice Guidelines on the management of extrahepatic cholangiocarcinoma
Recent years have witnessed significant advances in the imaging, molecular profiling, and systemic treatment of cholangiocarcinoma (CCA). Despite this…
000
Thor Halfdanarson @oncothor.bsky.social · 07/05/2025
Are you looking for a short update course in oncology this summer. Like a day-long course that covers recent data presented at ASCO and other recent meetings and publications. If so, we sure have the course for you. Online option also. @mayocliniccancer.bsky.social ce.mayo.edu/hematology-a...
ce.mayo.edu
010
Thor Halfdanarson @oncothor.bsky.social · 25/04/2025
It is not all about tumor shrinkage after PRRT. In this NETTER-1 analysis, PFS and OS were not different in patients where tumor shrinkage was seen. Not a new observation but a topic I discuss every week with patients. Benefits can be seen w/o high ORR... onlinelibrary.wiley.com/doi/10.1002/...
onlinelibrary.wiley.com
Relationship Between Best Tumor Shrinkage and Progression‐Free Survival and Overall Survival in Patients With Progressive Midgut Neuroendocrine Tumors Treated With [177Lu]Lu‐DOTA‐TATE: Ad Hoc Analysis of the Phase III NETTER‐1 Trial
We analyzed data from the phase III NETTER-1 study of 177Lu‑DOTATATE for patients with advanced midgut neuroendocrine tumors to explore whether tumor shrinkage is associated with durable efficacy. Al...
011
Thor Halfdanarson @oncothor.bsky.social · 23/04/2025
www.sciencedirect.com/science/arti...
sciencedirect.com
Adrenocortical carcinoma: a practical guide for clinicians
Adrenocortical carcinoma is a rare endocrine malignancy. The management of patients with adrenocortical carcinoma is challenging for several reasons, …
000
Thor Halfdanarson @oncothor.bsky.social · 18/04/2025
Wishing you had access to new and updated guidelines on MEN1...? Worry not, this team has you covered. www.sciencedirect.com/science/arti...
sciencedirect.com
American Association of Clinical Endocrinology Consensus Statement on Management of Multiple Endocrine Neoplasia Type 1
This document presents the findings of the American Association of Clinical Endocrinology (AACE) on the diagnosis, management, and surveillance of pat…
031
Thor Halfdanarson @oncothor.bsky.social · 18/04/2025
Time to rethink our approach to NET grading and use whole slide analysis (WSA) in addition to hotspot analysis (HSA) when assigning tumor grade using Ki-67? It certainly seems so.... @IHC_guy www.modernpathology.org/article/S089...
modernpathology.org
Optimal Approaches to Grading Entero-Pancreatic Neuroendocrine Tumors Using Ki-67 Proliferation Index (Hotspot and Whole Slide Digital Quantitative Analysis)
Grading neuroendocrine tumors using Ki-67 PI is essential for prognostic assessment and therapeutic decision-making. However, the absence of standardized guidelines has led to methodological inconsist...
061
Thor Halfdanarson @oncothor.bsky.social · 09/04/2025
Trying to summarize nuanced treatment decisions in one slide... What to do with small NF-pNETs? Who to observe? When to intervene...? What am I missing/getting wrong...?
041
Thor Halfdanarson @oncothor.bsky.social · 08/04/2025
Looking for a review on genomics in cancers of unknown primary...? Here you have it! As I have said before, every CUP patient seen in the Mayo CUP Clinic will have genomic testing. It is a somewhat surprisingly target-rich malignancy. www.sciencedirect.com/science/arti...
sciencedirect.com
Genomics in Cancer of Unknown Primary: Utility in Modern Clinical Practice
Cancer of unknown primary (CUP) is defined as metastatic cancer where the primary tumour responsible for metastatic spread cannot be identified despit…
000
Thor Halfdanarson @oncothor.bsky.social · 30/03/2025
DLL3 expression in high-grade NENs? Not rare at all! Check out this large study. 64% of NECs pos, 42% lung NETs, but only 5% GEPNETs are pos with the exception of G3 NETs which are 20% mod or strongly pos. DLL3-directed trials coming but not for G3 NETs. link.springer.com/article/10.1...
link.springer.com
DLL3 Expression in Neuroendocrine Carcinomas and Neuroendocrine Tumours: Insights From a Multicentric Cohort of 1294 Pulmonary and Extrapulmonary Neuroendocrine Neoplasms - Endocrine Pathology
Delta-like ligand 3 (DLL3) is frequently expressed in pulmonary small cell neuroendocrine carcinoma (SCNEC) and has emerged as a promising therapeutic target. However, limited data on DLL3 expression ...
020
Thor Halfdanarson @oncothor.bsky.social · 26/03/2025
What's happened in imaging for CUPs in the last decades, where are we now and where might we be going...? Very good overview with detailed tables of detection rates for different modalities. The stuff you need for your next talk or paper on CUP... academic.oup.com/bjr/advance-...
010
Thor Halfdanarson @oncothor.bsky.social · 25/03/2025
Are you interested in learning more about the management of small panc NETs and how molecular analysis may predict outcomes? If so, I have just the right paper for you... 😀 Thanks to @PancPathologist, Anna Vera Verschuur, C. Heaphy, L. Brosens et al. erc.bioscientifica.com/view/journal...
erc.bioscientifica.com
030
Thor Halfdanarson @oncothor.bsky.social · 25/03/2025
In case you needed a reminder of the not-so-predictable somatostatin receptor expression of lung NETs, here you have it... Keep in mind that only 44% had uniformly positive SSTR expression and some have none at all like this patient. jnm.snmjournals.org/content/64/1...
031
Thor Halfdanarson @oncothor.bsky.social · 21/03/2025
CUP oncology is increasingly precision oncology. Patient in 60s, extensive BRG-1 deficient undifferentiated poorly diff carcinoma of unknown primary. Near complete but not durable response to docetaxel/cisplatin/pembro followed by durable response to adagrasib for KRAS G12C mut.
000
Thor Halfdanarson @oncothor.bsky.social · 19/03/2025
Should we routinely add ICIs to chemo (platinum/etoposide) in extrapulmonary NECs? I think no. Yes, I realize the outcomes in advanced NEC are poor but we simply do not have the data yet. No benefit in this retrospective study. Enroll on SWOG S 2012!!! academic.oup.com/oncolo/artic...
academic.oup.com
Efficacy of atezolizumab combined with platinum and etoposide in the treatment of extrapulmonary neuroendocrine carcinoma
AbstractBackground. Neuroendocrine carcinoma (NEC) is an aggressive, poorly differentiated Grade 3 (G3) tumor with high nuclear and cellular atypia and Ki-
130
Thor Halfdanarson @oncothor.bsky.social · 15/03/2025
Why are you answering emails and working on a book chapter on a Saturday…? We could be out playing.
3180
Thor Halfdanarson @oncothor.bsky.social · 14/03/2025
If you were thinking of how nice it would be to have a recent review on functional NETs, you got one here courtesy of Francesca Spada and team. Excellent introduction to the fascinating world of functional NETs. www.sciencedirect.com/science/arti...
sciencedirect.com
Functioning neuroendocrine tumors (NET): Minimum requirements for a NET specialist
Functioning neuroendocrine tumors (f-NETs) represent a minority of all NETs, however their management is challenging due to the impact on patients’ su…
061
Thor Halfdanarson @oncothor.bsky.social · 14/03/2025
Still a little confused on the difference between grade and differentiation in panc NETs...? Need a quick primer on the pathology of pNETs including the genetic/molecular alterations. If so, Dr's. Rindi and Inzani have you covered. meridian.allenpress.com/aplm/article...
meridian.allenpress.com
Differentiation Versus Grade for Pancreatic Neuroendocrine Neoplasms
Context.—. Pancreatic neuroendocrine neoplasia (panNEN) is a tumor disease with distinctive morphology and often poses diagnostic challenges.Objective.—. To present and discuss the current diagnostic ...
052
Thor Halfdanarson @oncothor.bsky.social · 12/03/2025
It may still be dull, gray and brown but spring is in the air in Minnesota. Unseasonably warm day, the fields are freshly tilled and I am off today. What better than a good dose of gravel riding. Just what the doctor ordered…
010
Thor Halfdanarson @oncothor.bsky.social · 12/03/2025
Not sure about you but I find this depressing.. Of 5059 respondents, 47.7% reported fewer than 15 days of vacation in the last year, with 9.8% taking 5 or fewer days. Personally, I take 5-6 weeks off every year and rarely log into the EMR or do work. www.mayoclinicproceedings.org/article/S002...
mayoclinicproceedings.org
Association Between Vacation Characteristics and Career Intentions of US Physicians—A Cross-Sectional Analysis
To assess the association between physicians’ vacation characteristics and career intentions.
000
Thor Halfdanarson @oncothor.bsky.social · 12/03/2025
Look, I am posting a non-NET, non-CUP paper! Weekend warrior exercise does seem to have similar protective benefits as more regular exercise throughout the week. Very large study from the UK Biobank. What about us who do both...? 😀 www.mayoclinicproceedings.org/article/S002...
mayoclinicproceedings.org
Accelerometer-Derived
To examine the association of “weekend warrior” (WW) pattern and physical activity distributed throughout the week with mortality risk.
010
Thor Halfdanarson @oncothor.bsky.social · 28/02/2025
PRRT + PARP inhibitors in advanced NETs? To date, no trials have convincingly shown that PRRT + drug X (whatever that may be) is better than PRRT alone. The addition of PARPi seems to add little early toxicity but larger trials needed to show efficacy. jnm.snmjournals.org/content/earl...
jnm.snmjournals.org
177Lu-DOTATATE in Combination with PARP Inhibitor Olaparib Is Feasible in Patients with Somatostatin-Positive Tumors: Results from the LuPARP Phase I Trial
This phase I trial aimed to assess the feasibility and toxicity of combining the poly(adenosine diphosphate–ribose) polymerase inhibitor olaparib with 177Lu-DOTATATE in patients with somatostatin rece...
052
Thor Halfdanarson @oncothor.bsky.social · 25/02/2025
Who doesn't like good clinical reviews...? As my rectal cancer practice shrinks (and my NET/CUP/PDAC practice grows), I find this a great and practical, even as a seasoned GI oncologist. www.sciencedirect.com/science/arti...
sciencedirect.com
Total neoadjuvant treatment, non-operative management and radiotherapy-free strategies: New approaches for the management of proficient mismatch repair/microsatellite stable locally advanced rectal ca...
In recent years, new therapeutic approaches have emerged in addition to classical neoadjuvant (chemo)radiotherapy for the treatment of locally advance…
010
Thor Halfdanarson @oncothor.bsky.social · 23/02/2025
Preparing for the ENETS annual conference next month. Here is a simplified vision of what might be the future in the world of radioligand therapy for NETs (RLT which I now prefer over PRRT as a term...). Need better predictors of efficacy and tox I have never been good at predicting...
082
Thor Halfdanarson @oncothor.bsky.social · 21/02/2025
Do you want to know what is happening in radioligand therapy for patients with neuroendocrine tumors? What is hot and what is not...? if so this team (which has not yet migrated over to BlueSky...) has you covered... 😀 onlinelibrary.wiley.com/doi/10.1111/...
onlinelibrary.wiley.com
<em>Journal of Neuroendocrinology</em> | BSN Journal | Wiley Online Library
Neuroendocrine tumors encompass a wide range of tumors which originate from neural crest cells. These tumors were thought to be rare tumors, however, with the advent of advanced diagnostic techniques...
052
Thor Halfdanarson @oncothor.bsky.social · 21/02/2025
If you needed a reminder of the poor outcomes of patients with NECs, here you go. The current approach of platinum/etoposide yields the same disappointing results as in prior studies and outcomes of 2nd line therapy are poor. Better therapy sorely needed.
030
Thor Halfdanarson @oncothor.bsky.social · 21/02/2025
This is a valuable study on the changing epidemiology of colorectal NENs. Not surprisingly, there is increase in the incidence of well diff NETs but the incidence of NECs remains the same. Also not surprisingly, outcomes of colorectal NECs are poor. #oncsky
010
Thor Halfdanarson @oncothor.bsky.social · 18/02/2025
Liver resection in patients with high-grade neuroendocrine neoplasms, should that be considered...? Pts with G3 NET & NEC certainly have inferior outcomes but some may benefit from surgical debulking. Who are these patients? How can we better select? #oncsky www.sciencedirect.com/science/arti...
031
Thor Halfdanarson @oncothor.bsky.social · 18/02/2025
Performance of FDG PET in patients with CUP. Sensitivity and PPV were 58% and 92% and FDG PET therefore reasonable upfront imaging study. Others have reported similar findings but in our CUP clinic, the utility seems less. I would guess <30% sensitivity... www.thieme-connect.com/products/ejo...
thieme-connect.com
Role of 18FDG PET/CT in Detecting Primary Tumors in Patients with Carcinoma of Unknown Primary: Single-Center Cross-Sectional Study from 2017 to 2023 (Extension Study)
Thieme E-Books & E-Journals
010
Thor Halfdanarson @oncothor.bsky.social · 14/02/2025
Response assessment following PRRT in patients with metastatic NETs. Not as simple as one might have thought... Response heterogeneity in all patients in this small study. jnm.snmjournals.org/content/earl...
jnm.snmjournals.org
Full-Body Tumor Response Heterogeneity of Metastatic Neuroendocrine Tumor Patients Undergoing Peptide Receptor Radiopharmaceutical Therapy
Patients with metastatic neuroendocrine tumors (NETs) can present with hundreds of lesions, and each lesion might have a unique response pattern to peptide receptor radiopharmaceutical therapy (PRRT)....
011
Reposted by Thor Halfdanarson
Julie Hallet, MD MSc @halletjulie.bsky.social · 14/02/2025
What to do with carcinoid crisis? 🦓 A frequent concern for patients with #NETs having surgery We put together an international 🌎🌍🌏 multidisciplinary expert consensus statement 📢 Now open for feedback! Sign-up here 🔗 surveymonkey.com/r/periopcarc... 📆 Open until March 3rd!
175
Thor Halfdanarson @oncothor.bsky.social · 13/02/2025
Is the other ALT, alternative lengthening of telomeres, ready for routine use in pts w/ resected panc NETs...? I think so. In this study of large pNETs (≥3cm), ALT+ provided added prognostic info on recurrence but was not associated with OS. #oncsky onlinelibrary.wiley.com/doi/10.1111/...
100
Thor Halfdanarson @oncothor.bsky.social · 12/02/2025
Type 2 DM (DM2) and new-onset DM2 are associated with higher risk of pan NETs but longstanding DM2 was not. Nonsignificant association with family hx of PDAC and inverse association with alcohol use. No association with smoking, obesity and aspirin use. erc.bioscientifica.com/view/journal...
erc.bioscientifica.com
020
Thor Halfdanarson @oncothor.bsky.social · 10/02/2025
Can the therapy of grade 3 neuroendocrine neoplasms be distilled down to a single slide? Not sure, but here is my attempt for the upcoming NANETS Regional Conference in Mexico City next weekend... Lots of low-ish quality data and I left out the NABNEC data on nab-pacli + carbo.
020
Thor Halfdanarson @oncothor.bsky.social · 09/02/2025
Functional imaging in NECs and much more... Check out this excellent paper. Lots of goodies in here such as >90% of NECs and G3 NETs FDG PET pos. Also, 66% of NECs pos on SSTR PET. What does that mean? The SSTR is not (yet) a good NEC target. erc.bioscientifica.com/view/journal...
erc.bioscientifica.com
031
Thor Halfdanarson @oncothor.bsky.social · 09/02/2025
Here is an excellent review on cervical NECs, a deadly disease often affecting young women. A paper dedicated to the late Dr. Michael Frumovitz, a true expert on this rare entity. www.sciencedirect.com/science/arti...
sciencedirect.com
Neuroendocrine cervical carcinomas: genomic insights, controversies in treatment strategies, and future directions: a NeCTuR study
Neuroendocrine cervical carcinomas are rare, aggressive tumors with a high risk of early metastasis and poor survival outcomes. Despite existing thera…
152
Thor Halfdanarson @oncothor.bsky.social · 02/02/2025
It is not surprising to see that not all G2 panc NETs are created equal. Why would pNET w/ Ki67 of 4% behave the same as 20%. Indeed, they don't. Time to split up the G2 to G2a and G2b w/ 12% cutoff? G2b clearly more aggressive, more mets etc. link.springer.com/article/10.1...
link.springer.com
Subgrading of G2 Pancreatic Neuroendocrine Tumors as 2A (Ki67 3% to < 10%) Versus 2B (10% to ≤ 20%) Identifies Behaviorally Distinct Subsets in Keeping with the Evolving Management Protocols - Annals ...
Background Grade 1/2 PanNETs are mostly managed similarly, typically without any adjunct treatment with the belief that their overall metastasis rate is low. In oncology literature, Ki67-index of 10% ...
040
Thor Halfdanarson @oncothor.bsky.social · 31/01/2025
Unusual NET imaging this week: Tiny small bowel NET with metastasis to the right masticator space... Also a reminder that tiny sbNET primaries can have substantial mesenteric nodal mets. Stable without therapy but lanreotide was discontinued to to recurrent hypoglycemic episodes.
110
Thor Halfdanarson @oncothor.bsky.social · 30/01/2025
It’s a beautiful day in the Mayo neighborhood…
060
Thor Halfdanarson @oncothor.bsky.social · 29/01/2025
Just a reminder that NETs are radiosensitive tumors. Locally advanced, nonmetastatic, unresectable (extensive vascular involvement, cavernous portal vein transformation) G2 pancreatic NET (Ki67 9%). CAPTEM x12 with good partial response, followed by CRT with capecitabine. 23 mos post CRT #OncSky
070
Thor Halfdanarson @oncothor.bsky.social · 29/01/2025
Take good history and do a physical exam before ordering tests…
020
Thor Halfdanarson @oncothor.bsky.social · 29/01/2025
Another stressful morning commute… Soundtrack provided by Sturgill Simpson… 🤠
130
Thor Halfdanarson @oncothor.bsky.social · 24/01/2025
New epidemiology data on gastroenteropancreatic NETs (GEP-NETs) in the US. As I have said before and will continue saying, the incidence keeps rising (probably mostly from better diagnostic methods). jamanetwork.com/journals/jam...
jamanetwork.com
Gastroenteropancreatic Neuroendocrine Tumor Incidence by Sex and Age in the US
This observational study reports on a comprehensive nationwide evaluation of rising gastroenteropancreatic neuroendocrine tumor incidence in the US from 2001 to 2020.
062