Meta-analysis of postoperative radiotherapy versus radiochemotherapy for salivary gland cancer finds no significant survival difference

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Scientific reports Published May 7, 2026 Medically reviewed May 12, 2026 Study authors: Wilhelmy Anja, Schlattmann Peter, Guntinas-Lichius Orlando PubMed ↗ DOI ↗ By Dr. Julia Lee, PhD · Oncology, Genomics & Drug Development

Key Takeaway

Consider that evidence does not show PORT is inferior to PORCT for salivary gland cancer survival.

This systematic review and meta-analysis synthesized observational data on postoperative radiotherapy (PORT) versus postoperative radiochemotherapy (PORCT) for adults with salivary gland cancer. The analysis included 26,612 patients from highly confounded observational studies. The primary outcome was overall survival (OS). The meta-analysis found no statistically significant difference in overall survival between PORT and PORCT, with an effect size of 1.065 (95% CI: 0.998-1.137). A secondary analysis reported an HR of 1.153 (95% CI: 1.014-1.314) for a 10% change in the proportion of T4 patients. The authors synthesized findings from retrospective studies and noted that all included studies were retrospective and heterogeneous. They highlighted a high degree of uncertainty about the therapy effects, a highly confounded observational setting, and a lack of prospective clinical trials due to the rarity and large variety of histological subtypes. The analysis did not permit a reliable conclusion as to whether PORCT leads to better OS than PORT. Safety outcomes, adverse events, and practice relevance were not reported. The certainty of the evidence was noted as low.

Study Details

Study typeMeta analysis

Sample sizen = 4

EvidenceLevel 1

PublishedMay 2026

PMID42091689

View Original Abstract ↓

There is a lack of prospective clinical trials on the therapy of salivary gland cancer (SGC) due the rarity and large variety of histological subtypes. This study aimed to compare overall survival (OS) after primary surgery of SGC followed by postoperative radiotherapy (PORT) versus radiochemotherapy (PORCT) in curative intent. A systematic review and meta-analysis were performed on studies reporting OS after the two postoperative therapy modalities using hazard ratios (HRs) or allowing to calculate the HRs from the data. These studies were identified from PubMed, Web of Science, and Cochrane Library databases until October 2024. Pooled HR with 95% confidence interval (CI) is reported with random-effects or fixed-effects models. The search yielded 1,074 publications, of which 11 retrospective clinical studies with 26,612 adult patients could be included. None of the studies found a statistically significant difference between PORT and PORCT. Likewise, this meta-analysis revealed no statistically significant difference between PORT and PORCT. The pooled HR based on a common effect model was 1.065 (CI: 0.998-1.137) with low between study heterogeneity (I²=24.1%) and heterogeneity variance τ = 0.009. A meta-regression only revealed one factor with influence on the HR. The proportion of T4 patients in the total study shows a HR = 1.153 for a 10% change 95% CI: 1.014,1.314). This meta-analysis, based on a highly confounded observational setting, does not permit a reliable conclusion as to whether PORCT leads to better OS than PORT as adjuvant therapy for patients with SGC. PORCT might be beneficial for high-risk subgroups. However, this was not possible to determine in this meta-analysis as all included studies were retrospective and heterogeneous leading to a high degree of uncertainty about the therapy effects. More robust data from high-quality cohort studies or randomized controlled studies are needed. There is an urgent need for alternative and more effective multimodal treatment concepts for SGC.