This Week in Oncology — Aug 27, 2026

Welcome to This Week in Oncology. This week we're covering 10 notable papers spanning long-term adjuvant therapy across breast, kidney and lung cancer, radiotherapy dose and fractionation questions in prostate cancer, and new immunotherapy and combination strategies in liver, lung and colon cancer. Let's dive in.

We start with mature adjuvant data, where two long-running phase three trials reported extended follow-up in Annals of Oncology. In KEYNOTE-564, Haas and colleagues report the fourth prespecified interim analysis of one year of adjuvant pembrolizumab after nephrectomy in clear cell renal cell carcinoma at increased risk of recurrence, now with a median follow-up of about 70 months in nearly a thousand patients [1]. Disease-free survival remained better with pembrolizumab, reducing recurrence or death by roughly thirty percent, with five-year disease-free survival of about 61 percent versus 52 percent with placebo. Overall survival also favoured pembrolizumab, with about a third reduction in the risk of death and five-year survival just under 88 percent versus about 82 percent. Median overall survival has not been reached in either arm, and safety was essentially unchanged. For a practising oncologist, this is reassurance rather than a change of course: the survival benefit seen earlier has not eroded with five years of follow-up, which strengthens the case when you counsel a patient about accepting a year of immunotherapy after surgery. Alongside that, Garber and colleagues report the third interim analysis of OlympiA, one year of adjuvant olaparib in more than eighteen hundred patients with germline BRCA1 or BRCA2 pathogenic variants and high-risk HER2-negative early breast cancer, now at a median follow-up of 6.1 years [2]. Invasive disease-free survival, distant disease-free survival and overall survival all continued to favour olaparib, with roughly a third reduction in invasive recurrence and a reduction in death of about a quarter, translating to a six-year overall survival difference of about four percentage points. Importantly for the long-term conversation, there were fewer new BRCA-associated breast and ovarian or fallopian tube cancers with olaparib, and no signal of excess myelodysplastic syndrome or acute myeloid leukaemia. The benefit held in hormone receptor-positive high-risk disease, which is exactly the subgroup clinicians most often question.

Sitting neatly beside those data, the Journal of Clinical Oncology published the newest version of the ASCO living guideline on medical therapy for stage one to three hormone receptor-positive, HER2-negative breast cancer, drawing on forty-five randomised trials published since 2018 plus individual patient data meta-analyses [3]. The framing is worth noting: endocrine therapy remains the foundation, with chemotherapy and targeted agents layered on for selected patients, and the recommendations are now organised longitudinally, following the actual sequence of decisions from diagnosis through completion of systemic therapy, with a final section on estimating prognosis and absolute benefit. If you look after early breast cancer, this is the document to have open when you are integrating genomic assays, recurrence risk and patient preference.

Turning to prostate cancer, two randomised trials tackled radiotherapy dose and fractionation and came to rather different practical messages. In The Lancet Oncology, Hennequin and colleagues report GETUG AFU 18, which randomised 505 men with high-risk prostate cancer, all receiving long-term androgen deprivation, to 80 Gray versus the standard 70 Gray of prostate-targeted external beam radiotherapy [4]. At a median follow-up of about nine and a half years, five-year progression-free survival was 91 percent with dose escalation versus 88 percent with standard dose, and the separation widened by ten years, at about 84 percent versus 72 percent, corresponding to a reduction in progression or death of roughly forty-four percent. Crucially, acute grade three or worse toxicity was essentially identical, around a quarter in each arm, and late grade three toxicity was around seven to eight percent in both. The authors are appropriately cautious given the small number of early events, but this addresses a genuinely controversial question and supports 80 Gray as an option even when long-term androgen deprivation is already on board. Then in the Journal of Clinical Oncology, Song and colleagues randomised 316 men with biochemical recurrence after radical prostatectomy to salvage radiotherapy delivered either as 65 Gray in 26 fractions or the conventional 66 Gray in 33 fractions [7]. Here the primary endpoint was not met: four-year biochemical progression-free survival was about 80 percent with hypofractionation versus 78 percent with conventional treatment, so hypofractionation was not superior. Distant metastasis-free survival and cancer-specific survival were the same, and patient-reported quality of life was comparable, but grade two or worse gastrointestinal toxicity was higher with hypofractionation, about 8 percent versus under one percent, concentrated in men who did not have an endorectal balloon. So the honest reading is that a shortened salvage course is a reasonable convenience-driven alternative with equivalent cancer outcomes, not a better one, and rectal sparing measures matter.

In thoracic oncology, two Lancet Oncology papers address quite different points in the disease course. Le and colleagues report HARMONi, a double-blind phase three trial of ivonescimab, a bispecific antibody against PD-1 and vascular endothelial growth factor, added to pemetrexed and carboplatin in 438 patients with EGFR-mutated non-squamous lung cancer progressing after a third-generation tyrosine kinase inhibitor [6]. Progression-free survival improved substantially, from a median of about 4.4 months to 6.8 months, roughly halving the risk of progression or death. However, overall survival, a co-primary endpoint, was 16.8 versus 14.0 months and did not reach statistical significance. Serious treatment-related adverse events were nearly twice as common with ivonescimab, at 28 percent versus 15 percent, and there were four treatment-related deaths. So this is a positive progression-free survival result without confirmed survival benefit so far, and that nuance should shape how you discuss it. Meanwhile Dziadziuszko and colleagues report the safety and quality-of-life outcomes from ALINA, comparing 24 months of adjuvant alectinib with four cycles of platinum chemotherapy in 257 patients with resected ALK-positive disease [8]. Grade three or four events were uncommon with alectinib, dominated by creatine phosphokinase and transaminase elevations, serious treatment-related events were less frequent than with chemotherapy, and discontinuations for adverse events were about 5 percent versus 13 percent. Patients on alectinib reported clinically meaningful improvements at twelve weeks in bodily pain, physical role, mental health, social functioning and vitality, sustained across two years of treatment. That matters, because the main objection to two years of adjuvant targeted therapy is the burden of taking it.

Finally, three papers extend immunotherapy and staging into new territory. In The Lancet Oncology, Kudo and colleagues report EMERALD-3, which randomised 760 patients with embolisation-eligible hepatocellular carcinoma to durvalumab plus tremelimumab with lenvatinib plus transarterial chemoembolisation, the same immunotherapy doublet plus chemoembolisation, or chemoembolisation alone [5]. With a median follow-up of only about ten months, median progression-free survival in the triplet arm was 13.0 months; overall survival data remain immature, so this is an early read on a combination strategy rather than a definitive one. In Clinical Cancer Research, Shah and colleagues report the NEST phase two trial of neoadjuvant botensilimab, an Fc-enhanced CTLA-4 inhibitor, plus balstilimab in 24 patients with localised colon cancer [10]. Treatment did not delay surgery in any patient, and the major pathologic response rate was 41 percent in mismatch repair proficient tumours and 100 percent in the four deficient tumours, with immune profiling showing increased CD8 T-cell density and fewer regulatory T cells in responders. Response in mismatch repair proficient colon cancer is the notable part, though these are small numbers in a single-arm study. And in the Journal of Clinical Oncology, Mercolini and colleagues studied 301 children and adults with FDG-avid rhabdomyosarcoma who had both PET imaging and bilateral bone marrow aspirates and biopsies before treatment [9]. Against marrow sampling as the gold standard, PET had 98 percent sensitivity and 90 percent specificity, missing only one case, while identifying marrow disease in 24 patients where biopsy was negative. The practical conclusion is that when PET shows no FDG-avid marrow disease, routine bilateral marrow sampling can reasonably be omitted, sparing an invasive procedure, with imaging or biopsy reserved for FDG-avid marrow lesions.

If you only have time for one paper this week, make it GETUG AFU 18 in The Lancet Oncology [4]. It resolves a long-standing question about whether dose escalation still adds anything when men with high-risk prostate cancer are already receiving long-term androgen deprivation, and it does so with a decade of follow-up and no toxicity penalty.

Here are the key takeaways from this week in Oncology. First, five- and six-year follow-up confirms that one year of adjuvant pembrolizumab in high-risk clear cell kidney cancer and one year of adjuvant olaparib in germline BRCA-associated high-risk breast cancer both deliver durable disease-free and overall survival gains, with no late safety surprises. Second, in high-risk prostate cancer on long-term androgen deprivation, escalating prostate radiotherapy to 80 Gray improved long-term progression-free survival without added toxicity, while in the post-prostatectomy salvage setting, hypofractionation was not superior and carried more gastrointestinal toxicity when rectal sparing was not used. Third, adding ivonescimab to chemotherapy after progression on a third-generation EGFR inhibitor clearly delays progression but has not yet demonstrated a significant survival benefit, and it comes with more serious adverse events. Fourth, adjuvant alectinib's quality-of-life and safety profile supports the feasibility of two years of therapy in resected ALK-positive lung cancer. And fifth, in FDG-avid rhabdomyosarcoma with a PET-negative marrow, bilateral bone marrow sampling can reasonably be omitted.

That's your roundup for This Week in Oncology. The full transcript and references are available on the episode page in your AudioScholar library. This is an AI-curated summary — for clinical decisions, always consult primary sources and current guidelines. See you next week.

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This is an automated summary generated by artificial intelligence, which can make mistakes. Always review the original source materials.