Immune-boosting nutrition did not cut complications after bladder-cancer surgery

Feeding bladder-cancer patients a specialised "immune-enhancing" nutrition drink before and after surgery did not reduce complications, according to SWOG S1600, a phase 3 trial run through the US National Cancer Institute's clinical-trials network and published in JAMA Network Open [s1][s2]. A 30-day complication occurred in 62·2% of patients who drank the immunonutrition formula and 58·0% of those who drank a standard one — a difference that points the wrong way and does not approach statistical significance [s1].

Radical cystectomy — removing the bladder — is major surgery with high complication rates, and the idea that specific nutrients could prime the immune system to blunt those complications has circulated for years on limited evidence [s1]. S1600 was designed to test it properly, in a double-blind randomised trial across academic and community hospitals, and the answer it returned was flat.

What the trial tested

Adults with bladder cancer scheduled for radical cystectomy, who could swallow oral liquids and were not severely malnourished, were randomly assigned to one of two drinks taken three times daily for five days before and five days after surgery [s1]. Both drinks shared the same base formula; the immunonutrition version added L-arginine, omega-3 fatty acids, and dietary nucleotides — the components thought to modulate the post-surgical immune response [s1]. The trial was conducted at 13 US academic and community sites within the National Cancer Institute's National Clinical Trials Network and Community Oncology Research Program, and enrolled patients from March 5, 2019, through October 19, 2023 [s1].

The primary outcome was any 30-day complication graded 1 or higher on the standard Clavien-Dindo scale [s1]. The trial was powered on an assumption that would have been a large effect: a background complication rate of 65% and a 35% relative reduction from the intervention [s1]. Adherence was high — 94·5% — and was measured with a blood biomarker rather than self-report, so a null result cannot be explained away by patients not drinking the formula [s1].

What it found

Of 203 participants randomised (99 to immunonutrition, 104 to standard), 178 were evaluable for the primary outcome after withdrawals and missing data (90 immunonutrition, 88 standard) [s1]. The median age was 68·8 years and 162 participants (79·8%) were male [s1].

Any 30-day complication occurred in 62·2% of the immunonutrition group (56 of 90) and 58·0% of the standard group (51 of 88), an odds ratio of 1·18 (95% CI 0·64–2·18) [s1]. High-grade complications within 30 days were also similar: 11·1% (10 of 90) with immunonutrition versus 12·5% (11 of 88) with standard nutrition, an odds ratio of 0·86 (95% CI 0·34–2·17) [s1]. If anything, more adverse events — most commonly nausea — were reported in the immunonutrition group, 34·1% versus 20·5% [s1].

The one signal that leaned toward the intervention was in longer-term survival: two-year overall survival was 87·4% with immunonutrition versus 78·2% with standard nutrition, and disease-free survival 77·0% versus 67·5% [s1]. But these were secondary outcomes, the differences were not statistically significant, and a supportive-care drink around the time of surgery is not a plausible mechanism for changing cancer survival two years later [s1].

How to read it

The primary result is clear and clean: on the complication rate it was designed to move, immunonutrition did nothing [s1]. The trial was not underpowered by poor adherence, and the point estimate sat slightly against the intervention, so this is a genuine null rather than an inconclusive miss [s1]. The survival difference is the kind of secondary finding that invites over-reading; the authors themselves call for further mechanistic and subgroup work rather than a change in practice [s1].

Because S1600 ran through a publicly funded cooperative network rather than a nutrition-product manufacturer, it had no commercial reason to find a benefit, which makes a null result on a widely marketed category of products particularly useful [s1][s2]. It sits alongside other rigorously tested supportive measures — the contrast with an evidence-backed intervention is visible in coverage of what the trials actually show for cancer survivorship.

Why it matters

Immune-enhancing formulas are sold and recommended around many cancer operations, often on the strength of small or industry-linked studies [s1]. A properly powered, blinded, independent trial finding no reduction in complications is the sort of evidence that should temper routine use — and it spares patients the added nausea seen here for no measured benefit [s1].

What to watch

Whether pre-specified subgroups — by nutritional status, surgical approach, or tumour stage — reveal any patients who benefit is the obvious next analysis, and the authors flag it [s1]. The unexplained two-year survival gap, if it holds up in longer follow-up and other datasets, would need a mechanism before it could be believed [s1].

This article describes research and is not medical advice. Decisions about nutrition and care around cancer surgery are for patients and their treating clinicians.

Sources

• Immune-Enhancing Nutrition and Outcomes After Radical Cystectomy: A Randomized Clinical Trial (SWOG S1600) — JAMA Network Open, 1 July 2026
• Nutrition Therapy in Improving Immune System in Patients With Bladder Cancer That Can Be Removed by Surgery (NCT03757949) — ClinicalTrials.gov, U.S. National Library of Medicine, last updated 4 May 2026