Since human epidermal growth factor receptor-2 (HER2) characterization, going through clinical research and regulatory approval of HER2-targeted therapies, much has elapsed and is still unfolding. Hitherto, only breast cancer (BC) patients with HER2 immunohistochemistry 3+ or with HER2 gene fluorescence in-situ hybridization (FISH) amplification (a.k.a., HER2-positive BC) have benefited from anti-HER2 agents. In recent years, however, much of the research effort has been expanded, with positive outcomes being reached for formerly known HER2-negative BC that yet express HER2 to some degree (HER2 immunohistochemistry 1+ or 2+, but FISH negative) and are currently being classified as HER2-low BC for the purpose of trial enrollment. In this sense, our aim is to review the body of evidence of HER2-low BC that led to the study of first-generation anti-HER2 agents, like trastuzumab, and how they have failed to achieve any clinical applicability in this setting. In addition, we review new data that is leading to the growing success of the new generation of drugs, especially the promising HER2-directed antibody–drug conjugates. A narrative review is also performed regarding the rationale behind the consolidated and ongoing clinical trials studying anti-HER2 agents in combination with unrelated agents, such as immunotherapy, endocrine therapy, and CDK4/6 inhibitors. Hopefully, all this ongoing research effort will be able to extend the survival benefits seen with anti-HER2 agents in HER2-positive disease, at least to some degree, to the greater proportion of patients with HER2-low BC.

Background/methods: Although the prognosis of metastatic breast cancer (BC) has improved, some patients still develop high burden metastases or visceral crisis (VC) and polychemotherapy is commonly used in these cases. Data reporting the real effectiveness of this strategy are scanty. Therefore, the outcomes of patients with metastatic BC treated with platinum-based chemotherapy (P-ChT) at the Jules Bordet Institute during the period of January 2008 and December 2018 were retrospectively reviewed. The presence of VC was defined according to ABC 4 criteria. Results 441 patients were identified: visceral metastases were observed in 430 (97.5%) while 261 (59.2%) presented VC. As for metastatic BC subtype, 255 (57.8%) had ER-positive/HER2-negative, 41 (9.3%) ER-positive/HER2-positive, 34 (7.7%) ER-negative/HER2-positive and 111 (25.1%) triple-negative BC. Median number of prior treatment lines was 3.8 (0–12). Median OS with P-ChT in the entire cohort was 6.13 months. Patients with VC had lower OS than patients without VC (8.6 vs 3.7 months; p < 0.001). On multivariate analysis, the variables correlated with worse OS were hyperbilirubinemia (HR 1.90; 95% CI 1.34–2.75), ECOG ≥2 (HR 1.77; 95% CI 1.13–2.78) and ECOG ≥3 (HR 2.52; 95% CI 1.48–4.28), and >3 previous treatment lines (HR 2.27; 95% CI 1.53–3.21). Of the 261 patients with VC, 106 (40.5%) presented a resolution of the VC which correlated with better OS (9.3 vs 2.0 months, HR 0.27; 95% CI 0.21–0.36). Conclusion Patients who overcome VC benefit from P-ChT with OS similar to patients without VC. In this analysis, hyperbilirubinemia, poor ECOG and >3 previous treatment lines were significant prognostic factors in the overall study population.

PurposeOver the last decade, immune checkpoint inhibitors (ICI) have emerged as cornerstone in the treatment of many metastatic tumour types, including gastrointestinal cancers. In many solid tumours, the effective therapies in the metastatic field are progressively brought into the curative setting. Consequently, earlier tumoural settings have become a field of experiment for immunotherapies. In melanoma, lung, and bladder cancers, excellent results were recorded, possibly explained by differences in the tumour microenvironment between metastatic and non-metastatic settings. In gastrointestinal (GI) Oncology, nivolumab is the first immune checkpoint inhibitor to become a standard-of-care adjuvant treatment after curative surgery for oesophagal or gastroesophageal junction cancer.Recent findingsWe herein discuss the results of a selection of the most relevant studies presented/published over the last 18 months testing immunotherapies in non-metastatic GI cancers. Among immunotherapies, ICI have been investigated in pre-, peri- and postoperative setting across tumour types, alone or in combination with chemo- and/or radiotherapy. Vaccines are also a new field of investigation.SummaryPromising results from two studies (NCT04165772 and NICHE-2 study) demonstrating never-seen-before responses to neoadjuvant immunotherapy in MMR deficient (dMMR) colorectal cancers raise hope for improving the patients’ outcome and developing organ-sparing strategies in this situation.

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