Search

Aims: The aim of this study was to assess the incidence of reinfection in patients after two-stage revision of an infected megaprosthesis (MPR) implanted after resection of a bone tumour., Methods: A retrospective study was carried out of 186 patients from 16 bone sarcoma centres treated between January 2010 and December 2020. The median age at the time of tumour diagnosis was 26 years (IQR 17 to 33); 69 (37.1%) patients were female, and 117 (62.9%) were male., Results: A total of 186 patients with chronic MPR infections were included. Median follow-up was 68 months (IQR 31 to 105). The most represented sites of MPR were distal femur in 93 cases (50.0%) and proximal tibia in 53 cases (28.5%). Polymicrobial infections were seen in 34 cases (18.3%). The most frequent isolated pathogens were staphylococci. Difficult-to-treat (DTT) pathogens were isolated in 50 cases (26.9%). The estimated infection recurrence (IR) rate was 39.1% at five years and 50.0% at ten years. A higher IR rate was found in DTT PJI compared to non-DTT infections (p = 0.019). Polymicrobial infections also showed a higher rate of infection recurrence (p = 0.046)., Conclusion: This study suggests that an infected MPR treated by two-stage revision and ultimately reimplantation with a MPR can be successful, but the surgeon must be aware of a high recurrence rate compared to those seen with infected conventional implants., Competing Interests: L. Jeys reports consulting fees from Implantcast, unrelated to this study. A. Leithner reports institutional educational grants from Johnson & Johnson, Alphamed, and Medacta, unrelated to this study. P. Ruggieri reports royalties or licenses from Exactech and Stryker, unrelated to this study, and holds unpaid positions as Vice President of EFORT, Secretary General of ISOLS, and is a member of the Board of Directors for the University of Padova. M. A. Smolle reports travel grants from Alphamed Fischer, Implantcast, ImplanTec, and Pharmamar, unrelated to this study. M. A. J. van de Sande reports a department research grant from Implantcast, unrelated to this study, and is also Vice President of EMSOS., (© 2025 The British Editorial Society of Bone & Joint Surgery.)

Assessing the response to oncological treatments is paramount for determining the prognosis and defining the best treatment for each patient. Several biomarkers, including imaging, can be used, but standardization is fundamental for consistency and reliability. Tumor response evaluation criteria have been defined by international groups for application in pharmaceutical clinical trials evaluating new drugs or therapeutic strategies. RECIST 1.1 criteria are exclusively based on unidimensional lesion measurements; changes in tumor size are used as surrogate imaging biomarkers to correlate with patient outcomes. However, increased tumor size does not always reflect tumor progression. The introduction of immunotherapy has led to the development of new criteria (iRECIST, Level of Evidence (LoE) Ib) that consider the possibility that an increase in disease burden is secondary to the immune response instead of progression, with the new concept of Unconfirmed Progressive Disease (a first progression event which must be confirmed on follow-up). Specific criteria were devised for HCC (mRECIST, LoE IV), which measure only enhancing HCC portions to account for changes after local therapy. For GIST treated with imatinib, criteria were developed to account for the possible increase in size reflecting a response rather than a progression by assessing both tumor size and density on CT (Choi, LoE II). This article provides concise and relevant practice recommendations aimed at general radiologists to help choose and apply the most appropriate criteria for assessing response to treatment in different oncologic scenarios. Though these criteria were developed for clinical trials, they may be applied in clinical practice as a guide for day-to-day interpretation. KEY POINTS: Response evaluation criteria, designed for use in clinical trials, might serve as a surrogate biomarker for overall survival. RECIST 1.1 defines measurable and non-measurable disease among which target lesions and non-target lesions are selected at baseline as reference for follow-ups. Some therapies and/or cancers require the use of different criteria, such as iRECIST, mRECIST, and Choi criteria., Competing Interests: Compliance with ethical standards. Guarantor: The scientific guarantor of this publication is G.A.Z. Conflict of interest: M.D.A.: Consultant and Scientific Advisory Board Member for Keosys Medical Imaging. L.F.: Speaker fees: Fujifilm, GE Healthcare; Research collaboration/grants: Bristol-Myers-Squibb, Philips, Dassault Systems; Scientific committee: Institut Servier. G.A.Z. is the Deputy Editor of European Radiology. She has not taken part in the review or selection process of this article. C.C. is a member of the European Radiology Scientific Editorial Board. He has not taken part in the review or selection process of this article. H.-P.S. is a member of the European Radiology Advisory Editorial Board. He has not taken part in the review or selection process of this article. The other authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article. Statistics and biometry: No complex statistical methods were necessary for this paper. Informed consent: Written informed consent was not required. Ethical approval: Institutional Review Board approval was not required. Study subjects or cohorts overlap: Not applicable. Methodology: Practice recommendations, (© 2024. The Author(s).)

Imaging is used for lymphoma detection, Ann Arbor/Lugano staging, and treatment response assessment. [ 18 F]FDG PET/CT should be used for most lymphomas, including Hodgkin lymphoma, aggressive/high-grade Non-Hodgkin lymphomas (NHL) such as diffuse large B-cell lymphoma, and many indolent/low-grade NHLs such as follicular lymphoma. Apart from these routinely FDG-avid lymphomas, some indolent NHLs, such as marginal zone lymphoma, are variably FDG-avid; here, [ 18 F]FDG PET/CT is an alternative to contrast-enhanced CT at baseline and may be used for treatment response assessment if the lymphoma was FDG-avid at baseline. Only small lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL) should exclusively undergo CT at baseline and follow-up unless transformation to high-grade lymphoma is suspected. While [ 18 F]FDG PET/CT is sufficient to rule out bone marrow involvement in Hodgkin lymphoma, biopsy may be needed in other lymphomas. The 5-point (Deauville) score for [ 18 F]FDG PET that uses the liver and blood pool uptake as references should be used to assess treatment response in all FDG-avid lymphomas; post-treatment FDG uptake ≤ liver uptake is considered complete response. In all other lymphomas, CT should be used to determine changes in lesion size; for complete response, resolution of all extranodal manifestations, and for lymph nodes, long-axis decrease to ≤ 1.5 cm are required. KEY POINTS: [ 18 F]FDG-PET/CT and contrast-enhanced CT are used to stage lymphoma depending on type. Imaging is required for staging, and biopsies may be required to rule out bone marrow involvement. For treatment response assessment, the 5-PS (Deauville) score should be used; in a few indolent types, CT is used to determine changes in lesion size., Competing Interests: Compliance with ethical standards. Guarantor: The scientific guarantor of this publication is Marius E. Mayerhoefer. Conflict of interest: The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article. Statistics and biometry: No complex statistical methods were necessary for this paper. Informed consent: Written informed consent was not required. Ethical approval: Institutional Review Board approval was not required. Study subjects or cohorts overlap: Not applicable. Methodology: Practice recommendations, (© 2024. The Author(s).)