Oncology Meeting Digest

2026-05-17

digest generated 2026-05-18

OLIGOCARE prospective registry (EORTC, ~2500 patients, ~3500 lesions) reports 5% local failure at 1 year and 11% at 3 years after SABR for oligometastatic disease, with minimum PTV dose independently correlated with outcome.
TL;DR
ESTRO26 Day 3 was dominated by mature radiotherapy trial data: four long-term breast RT trials (10 to 20 years of follow-up) reported, though full effect sizes were not captured in available source tweets. The OLIGOCARE registry provides the most concrete results, confirming durable SABR local control across oligometastatic histologies with colorectal cancer as the highest-risk subgroup. RCC SBRT achieved 100% local control at 5 years in a separate series.

Breast

Four randomized or prospective breast trials reported at ESTRO26, spanning oligometastatic disease management to 20-year nodal irradiation follow-up.

IMPORT HIGH (ISRCTN47437448)

Ten-year results of dose-escalated simultaneous integrated boost RT in early breast cancer presented by Charlotte Coles; no effect size reported in source tweets.

  • Dose-escalated simultaneous integrated boost radiotherapy vs standard RT in early breast cancer.
  • Ten-year follow-up; presented at ESTRO26 by Charlotte Coles.
  • Tweet text truncated; specific outcomes not captured in available source.
📚 Sources (1)

APBI-IMRT Florence Phase III

Fifteen-year outcomes of accelerated partial breast irradiation vs whole-breast irradiation in early breast cancer presented; no effect size reported in source tweets.

  • Phase III trial of APBI vs WBI in early breast cancer; 15-year follow-up.
  • Presented by Icro Meattini and Carlotta B at ESTRO26.
  • Specific endpoint results not captured in available tweet text.
📚 Sources (1)

EORTC 22922/10925

Twenty-year results of internal mammary and medial supraclavicular irradiation in stage I-III breast cancer, including a pN0 subgroup, presented; no effect size reported in source tweets.

  • Randomized trial of IM/MSC nodal irradiation in stage I-III breast cancer; 20-year follow-up.
  • Joint presentation by Philip Poortmans and Orit Kaidar-Person at ESTRO26.
  • Analysis includes pN0 patients, extending benefit signal to node-negative disease.
  • Specific DFS, OS, or nodal recurrence data not captured in available tweet text.
📚 Sources (1)

OLIGOMA Trial (ARO-2021-09, NCT04495309) NCT04495309

Metastases-directed treatment in oligometastatic breast cancer reported from OLIGOMA; no effect size reported in source tweets.

  • ARO-2021-09, NCT04495309; prospective trial of metastases-directed treatment in oligometastatic breast cancer.
  • Presented by David Krug at ESTRO26.
  • Specific outcomes not captured in available tweet text.
📚 Sources (1)

Breast RT + Endocrine Therapy Adherence (unnamed trial)

Unnamed trial confirms optimal local control with RT plus endocrine therapy, with suboptimal ET adherence identified as a persistent issue; no effect size reported.

  • Commentary by @Sushilberiwal at ESTRO26; specific trial not named in source tweet.
  • Optimal locoregional control achieved with combined RT and ET despite adherence gaps.
  • Five-fraction RT framed as simplifying the locoregional treatment decision.
  • Suboptimal ET adherence flagged as a limiting factor independent of RT delivery.
📚 Sources (1)
Open questions
  • Does IM/MSC irradiation confer survival benefit in pN0 patients at 20 years, or does late cardiac toxicity offset gain?
  • How does suboptimal ET adherence modulate the local control benefit seen with 5-fraction RT?
  • What is the optimal MDT strategy for oligometastatic breast cancer per OLIGOMA: ablation alone vs systemic intensification vs both?

Prostate

Two trial frameworks at ESTRO26 address optimal fractionation and nodal irradiation in high-risk prostate cancer with ADT.

PRIME Trial

PRIME compares moderate hypofractionation (~68 Gy/25 fractions) vs SBRT (36.25 Gy/5 fractions) with pelvic nodal irradiation in biologically aggressive prostate cancer plus ADT; design-only tweet, no outcomes reported.

  • Moderate hypofractionation arm: ~68 Gy/25 fractions/5 weeks.
  • SBRT arm: 36.25 Gy/5 fractions/1-2 weeks.
  • Both arms include pelvic nodal irradiation plus ADT; framed as companion to HYPO RT PC.
  • No outcome data in source tweet; design description only.
📚 Sources (1)

POP RT vs PEACE II Comparison

Discussion tweet contrasts POP RT (2yr ADT + whole-pelvis RT) vs PEACE II (3yr ADT + prostate-only RT); no outcome data reported.

  • POP RT: 2 years ADT plus whole-pelvis radiotherapy.
  • PEACE II: 3 years ADT plus prostate-only radiotherapy.
  • Author poses the treatment-selection question without reporting comparative outcomes.
📚 Sources (1)
Open questions
  • Is shorter ADT with whole-pelvis RT equivalent to longer ADT with prostate-only RT in high-risk disease?
  • Can SBRT replace moderate hypofractionation when pelvic nodal coverage is required, and what does PRIME show on toxicity?

Oligometastatic / Mets

OLIGOCARE is the largest prospective registry of SABR for oligometastatic disease, now reporting multi-year local control outcomes across histologies.

OLIGOCARE Registry (EORTC, e2irradiate)

OLIGOCARE reports 5% local failure at 1 year and 11% at 3 years after SABR across ~2500 patients and ~3500 lesions, with minimum PTV dose correlated with outcome.

  • Prospective EORTC e2irradiate registry; ~2500 patients, ~3500 oligometastatic lesions treated with SABR.
  • Local failure rate: 5% at 1 year, 11% at 3 years.
  • Colorectal cancer histology associated with higher local progression risk vs other primaries.
  • Minimum PTV dose independently correlated with local control outcomes.
📚 Sources (1)
Open questions
  • Does minimum PTV dose as a predictive metric justify prospective dose-escalation strategies, particularly in colorectal oligomets?
  • What systemic therapy backbone was concurrent across OLIGOCARE histologies, and does it confound local failure rates?

Kidney

RCC SBRT Case Series

SBRT for renal cell carcinoma achieves 100% local control at 5 years; study design and sample size not reported in source tweet.

  • Commentary tweet by @TylerSbrt referencing presented results at ESTRO26.
  • Local control: 100% at 5 years for RCC treated with SBRT.
  • No sample size, fractionation scheme, or study name reported in source tweet.
📚 Sources (1)