Brian Shields
ESMO 2026 (Madrid, Oct 23–27): 1,199 physicians posted or reposted on 94 trials across lung, breast, GU and GI cancer on X. We mapped who drove each conversation, who amplified it, where those physicians practice, and which trials they engaged with. Eight network maps, four tumor types, all public.
Key numbers
- Lung: 550 physicians. Media accounts produced 43.7% of impressions.
- Breast: 307 physicians. Yakup Ergün's posts reached 79.6K impressions, nearly double the next physician.
- GU: 534 physicians. Tom Powles was amplified by 175 accounts. VOLGA engaged 291 physicians.
- GI: 431 physicians. 68.7% practice outside the US. None of the 7 GI presenters and discussants posted their own data.
- 351 physicians showed up in two or more tumor networks. 88 showed up in all four.
| Lung | Breast | GU | GI | |
|---|---|---|---|---|
| Posts | 947 | 597 | 651 | 529 |
| Trials | 24 | 25 | 18 | 27 |
| Accounts | 1,209 | 677 | 964 | 864 |
| US physicians | 197 | 107 | 185 | 135 |
| International physicians | 353 | 200 | 349 | 296 |
| Physician countries | 53 | 38 | 54 | 49 |
What are the influencer and attendee network maps?
Two maps per tumor type.
The influencer network shows whose posts reached people, who amplified them, and how physicians connect across countries. It includes the top voices, the top amplifiers, a state map of US physicians, a country breakdown and the full network graph.
The virtual attendee network shows who took part. Click any of the top 20 KOLs and every chart filters to the accounts that amplified that KOL: physicians vs media vs industry, US vs international, and the named accounts. The trial chart lists the physicians who engaged with each trial.
Who drove the ESMO 2026 lung cancer conversation?
Hidehito Horinouchi led at 81.6K impressions. Stephen Liu 63.8K. Yakup Ergün 43.8K. Masahiro Torasawa 40.0K from 6 posts. Enes Erul 24.4K from 2 posts.
Lung was the largest network: 947 posts, 550 physicians, 53 physician countries. It was also the most media-driven. Media accounts produced 43.7% of impressions. NEJM alone produced 215K.
Only 1 of 10 lung presenters posted their own data.
Trials by physicians engaged: DeLLphi-305 353, KRASCENDO-1 196, SAFFRON 175, OptiTROP-Lung06 141, PERSEE 114. DeLLphi-305 came from 271 posts. No single post reached more than 41 of those physicians.
Horinouchi was amplified by 114 accounts, including physicians in 21 countries. Japan and the UK tied for the most international physicians, 32 each. US: New York 27, California 15, Florida 14, Massachusetts 14, Texas 14.
Who drove the ESMO 2026 breast cancer conversation?
Yakup Ergün: 79.6K impressions, nearly double Sara Tolaney (41.1K). Then Oncology Brothers 35.0K, Paolo Tarantino 33.9K, Amol Akhade 19.2K.
Breast presenters posted more than any other tumor: Hope Rugo (KEYNOTE-B49) 14.5K, Sarah Sammons (BRIDGET) 12.6K, Sherene Loi (SWITCH discussant) 3.9K.
Abi Siva amplified 18 of the top 20 breast KOLs, more than any other physician.
Italy–US was the strongest cross-border link (42). Tarantino, Lambertini, Bonzano, Bianchini, Agostinetto and Meattini drove it.
Trials: NATALEE 157 physicians, TALENT 98, postMONARCH 83, PANKU-Breast01 78, VIKTORIA-1 77. TALENT reached 98 physicians from 34 posts. One recap post reached 36 of them.
Who drove the ESMO 2026 GU cancer conversation?
Tom Powles 59.3K impressions. Oncology Brothers 46.0K. Toni Choueiri 44.9K. Zach Klaassen 38.9K. Yüksel Ürün 23.0K. Seven of the top 10 are US-based.
GU was the most physician-heavy network: 534 physicians, 55.4% of all accounts. It was also the most connected (2,113 links) and the least concentrated. The top 10 accounts held 43.9% of impressions.
VOLGA engaged 291 physicians. Then DASL-HiCaP 200, KEYNOTE-B15/EV-304 164, KEYNOTE-866 158, KEYNOTE-905/EV-303 158.
Five of the top six were perioperative MIBC trials. Physicians discussed them side by side.
"Six phase III trials. Six different stories." — Yüksel Ürün (@DrYukselUrun)
US–UK was the strongest cross-border pair (67 links). Latin America had 71 physicians, its strongest showing in any tumor.
Who drove the ESMO 2026 GI cancer conversation?
Arndt Vogel 52.5K impressions. Nieves Martinez Lago 45.5K. Oncology Brothers 40.2K. Yakup Ergün 36.7K. Nicholas Hornstein 36.1K. Eight of the top 10 practice outside the US.
GI was the most international network. 68.7% of its 431 physicians practice outside the US. 77% of physician links crossed a border. Physicians, not media, carried the reach: 78.3% of impressions.
None of the 7 GI presenters and discussants posted their own data. Eileen O'Reilly amplified 12 of the top 20 GI KOLs instead.
Trials: CLARITY-Gastric01 118 physicians, MASTERPLAN 118, HARMONi-GI1 114, SANO 97, RASolute 302 84. MASTERPLAN tied CLARITY-Gastric01 from 21 posts against 64. One thread by radiation oncologist Shankar Siva reached 65 of those physicians.
How do the four tumor networks compare?
| Lung | Breast | GU | GI | |
|---|---|---|---|---|
| Physicians' share of impressions | 52.2% | 60.8% | 74.3% | 78.3% |
| Media's share of impressions | 43.7% | 34.8% | 22.6% | 15.9% |
| Physicians outside the US | 64.2% | 65.1% | 65.4% | 68.7% |
| Accounts amplifying the top voice | 114 | 103 | 175 | 145 |
| Presenters who posted on X | 1 of 10 | 3 of 6 | 4 of 7 | 0 of 7 |
1,199 physicians across the four networks. 351 in two or more. 88 in all four.
Oncology Brothers ranked top 5 in every tumor. Amol Akhade top 20 in all four. Yakup Ergün #1 in breast, #3 in lung, #4 in GI. Shankar Siva top 20 in GU and GI.
Dana-Farber was a top-four institution in every tumor. MSK led GU and tied Dana-Farber in GI
US Networks: Lung vs GI Oncology
How do MSLs, medical affairs and pharma teams use these maps?
MSLs. Start with the trial. VOLGA: 291 physicians. Filter to your territory on the state map: New York 27, California 21, Texas 19, Tennessee 10 in GU. Read each physician's posts before the visit.
Medical affairs. 351 physicians cross tumor lines. Separate tumor plans count them twice. Physicians outside the US were 64% to 69% of every network. Veeva's field data says nearly 70% of KOLs interact with only one company's field medical team (vendor data).5
Brand and marketing. Channel mix depends on the tumor. Lung: media produced 43.7% of impressions. GI: physicians produced 78.3%. The amplifier board shows who distributes. Abi Siva amplified 18 of the top 20 breast KOLs.
Competitive intelligence. Physicians engaged per trial is share of voice. Check what drove the count. DeLLphi-305's 353 came from 271 posts. MASTERPLAN's 118 came from 21.
KOLs. Click your name on the attendee page to see who carries your posts. Powles: 175 accounts, 109 physicians, 26 countries.
Why map the social conversation at a congress?
Most physicians are online. Few post. In a 2021 JAMA Network Open study, 70.6% of physicians had a public social profile and 89.3% of those posted zero times a month.1 The physicians who do post, and the ones who repost them, set what the rest see.
ASCO tweet authors grew from 1,429 in 2011 to 15,796 in 2016.2 In a 2024 Sermo/LiveWorld survey of 317 US physicians, 60% said KOL or influencer content on social media changed their perception of a medication. Both companies sell physician social services.3
Public conference analytics have thinned out. Symplur's hashtag platform "is no longer available due to recent changes with X API access."4
Enterprise platforms like Veeva Link, IQVIA and H1 cover publications, claims, CRM and year-round activity across therapeutic areas. These maps are narrower: one congress, one tumor type, physicians separated from media and industry, who amplified whom, and which trials each physician engaged with. Open Payments is US-only and updates once a year; the next release is January 2027.6
Frequently asked questions
How many physicians discussed ESMO 2026 on X?
1,199 across lung, breast, GU and GI. Lung 550, GU 534, GI 431, breast 307.
Which ESMO 2026 trial engaged the most physicians?
DeLLphi-305 in lung, 353 physicians. VOLGA led GU (291), NATALEE led breast (157), CLARITY-Gastric01 and MASTERPLAN tied in GI (118).
Who were the top ESMO 2026 KOLs on X?
Lung: Hidehito Horinouchi. Breast: Yakup Ergün. GU: Tom Powles. GI: Arndt Vogel.
Which tumor type was most international?
GI. 68.7% of physicians practice outside the US and 77% of physician links crossed a border.
Are the maps free?
Yes. All eight are public at kolpulse.com.
The eight maps
- Lung: influencer network · attendee network
- Breast: influencer network · attendee network
- GU: influencer network · attendee network
- GI: influencer network · attendee network
Sources
1. Hameed I, et al. JAMA Netw Open 2021;4:e2118213. PMC8299311
2. Pemmaraju N, et al. J Oncol Pract 2017. PMID 28514195
3. MedPage Today, Oct 15, 2024 (Sermo/LiveWorld survey, 317 US physicians). medpagetoday.com
4. Symplur. symplur.com
5. Veeva Pulse Field Trends Report, 1Q–2Q 2023. veeva.com
6. CMS Open Payments. openpaymentsdata.cms.gov
