Background Survival in mycosis fungoides (MF) is varied and may be poor. The PROCLIPI (PROspective Cutaneous Lymphoma International Prognostic Index) study is a web‐based data collection system for early‐stage MF with legal data‐sharing agreements permitting international collaboration in a rare cancer with complex pathology. Clinicopathological data must be 100% complete and in‐built intelligence in the database system ensures accurate staging. Objectives To develop a prognostic index for MF. Methods Predefined datasets for clinical, haematological, radiological, immunohistochemical, genotypic, treatment and quality of life are collected at first diagnosis of MF and annually to test against survival. Biobanked tissue samples are recorded within a Federated Biobank for translational studies. Results In total, 430 patients were enrolled from 29 centres in 15 countries spanning five continents. Altogether, 348 were confirmed as having early‐stage MF at central review. The majority had classical MF (81·6%) with a CD4 phenotype (88·2%). Folliculotropic MF was diagnosed in 17·8%. Most presented with stage I (IA: 49·4%; IB: 42·8%), but 7·8% presented with enlarged lymph nodes (stage IIA). A diagnostic delay between first symptom development and initial diagnosis was frequent [85·6%; median delay 36 months (interquartile range 12–90)]. This highlights the difficulties in accurate diagnosis, which includes lack of a singular diagnostic test for MF. Conclusions This confirmed early‐stage MF cohort is being followed‐up to identify prognostic factors, which may allow better management and improve survival by identifying patients at risk of disease progression. This study design is a useful model for collaboration in other rare diseases, especially where pathological diagnosis can be complex.

ALK-positive histiocytosis is a rare subtype of histiocytic neoplasm first described in 2008 in 3 infants with multisystemic disease involving the liver and hematopoietic system. This entity has subsequently been documented in case reports and series to occupy a wider clinicopathologic spectrum with recurrent KIF5B-ALK fusions. The full clinicopathologic and molecular spectra of ALK-positive histiocytosis remain, however, poorly characterized. Here, we describe the largest study of ALK-positive histiocytosis to date, with detailed clinicopathologic data of 39 cases, including 37 cases with confirmed ALK rearrangements. The clinical spectrum comprised distinct clinical phenotypic groups: infants with multisystemic disease with liver and hematopoietic involvement, as originally described (Group 1A: 6/39), other patients with multisystemic disease (Group 1B: 10/39), and patients with single-system disease (Group 2: 23/39). Nineteen patients of the entire cohort (49%) had neurologic involvement (7 and 12 from Groups 1B and 2, respectively). Histology included classic xanthogranuloma features in almost one-third of cases, whereas the majority displayed a more densely cellular, monomorphic appearance without lipidized histiocytes but sometimes more spindled or epithelioid morphology. Neoplastic histiocytes were positive for macrophage markers and often conferred strong expression of phosphorylated extracellular signal-regulated kinase, confirming MAPK pathway activation. KIF5B-ALK fusions were detected in 27 patients, whereas CLTC-ALK, TPM3-ALK, TFG-ALK, EML4-ALK, and DCTN1-ALK fusions were identified in single cases. Robust and durable responses were observed in 11/11 patients treated with ALK inhibition, 10 with neurologic involvement. This study presents the existing clinicopathologic and molecular landscape of ALK-positive histiocytosis and provides guidance for the clinical management of this emerging histiocytic entity.

The BJC is owned by Cancer Research UK, a charity dedicated to understanding the causes, prevention and treatment of cancer and to making sure that the best new treatments reach patients in the clinic as quickly as possible. The journal reflects these aims. It was founded more than fifty years ago and, from the start, its far-sighted mission was to encourage communication of the very best cancer research from laboratories and clinics in all countries. The breadth of its coverage, its editorial independence and it consistent high standards, have made BJC one of the world's premier general cancer journals. Its increasing popularity is reflected by a steadily rising impact factor.

Patients aged <65 years with peripheral T-cell lymphoma (PTCL) are treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP). Although the addition of etoposide (CHOEP) and consolidation with autologous stem cell transplantation (ASCT) are preferred in some countries, randomized trials are lacking. This nationwide population-based study assessed the impact of etoposide and ASCT on overall survival (OS) among patients aged 18 to 64 years with stage II to IV anaplastic large-cell lymphoma (ALCL), angioimmunoblastic T-cell lymphoma (AITL), or PTCL not otherwise specified (NOS) diagnosed between 1989 and 2018 using the Netherlands Cancer Registry. Patients were categorized into 2 calendar periods, representing pre- and post-eras of etoposide and ASCT, respectively. A total of 1427 patients were identified (ALCL, 35%; AITL, 21%; and PTCL NOS, 44%). OS increased from 39% in the period from 1989 to 2009 to 49% in the period of 2009 to 2018 (P < .01). Five-year OS was superior for patients treated with CHOEP vs CHOP (64% and 44%, respectively; P < .01). When adjusted for subtype, International Prognostic Index score, and ASCT, the risk of mortality was similar between the 2 groups, except for patients with ALK+ ALCL, for whom the risk of mortality was 6.3 times higher when treated with CHOP vs CHOEP. Patients undergoing consolidation with ASCT had superior 5-year OS of 81% compared with 39% for patients not undergoing ASCT (P < .01), regardless of whether complete remission was achieved. In patients aged <65 years with advanced-stage ALK− ALCL, AITL, or PTCL, the use of ASCT consolidation, but not the addition of etoposide, was associated with improved OS.

Objectives: Osteonecrosis of the jaw (ONJ) is a serious adverse event of bone resorption inhibitors (BRIs), such as bisphosphonates and denosumab. Bisphosphonates and denosumab inhibit osteoclast function through different pharmacological effects and bisphosphonates are retained in bone for several months to years. Sequential treatment with bisphosphonates and denosumab might lead to an overlapping treatment effect, due to the addition of the effect of denosumab on the residual bisphosphonate effect. Therefore, the aim of our study was to investigate if switching from denosumab to bisphosphonates is associated with a higher incidence of ONJ. Methods: We retrospectively reviewed records of patients with solid tumors and bone metastases treated with denosumab after prior treatment with bisphosphonates at the University Hospitals Leuven (sequential group). Patients treated with denosumab or bisphosphonates alone were used as control groups. Results: We identified 110 patients sequentially treated with bisphosphonates and denosumab with a median total BRI exposure of 36 months (sequential group). Median bisphosphonates exposure was 16 months and median denosumab exposure was 13 months. About 299 patients were included in the bisphosphonates control group with a median bisphosphonate exposure 19 months. About 6.7% (20/299) of patients developed ONJ. About 240 patients were included in the denosumab control group with a median denosumab exposure 17.5 months. About 10.0% of patients (24/240) developed ONJ. In the sequential group, 15.5% of patients (17/110) developed ONJ. The incidence of ONJ was 1.8% (2/110), 6.3% (6/99), 4.9% (4/82), 5.6% (3/54), and 3.4% (1/29), respectively in the first, second, third, fourth, and fifth year of BRI exposure, an ONJ-incidence similar to ONJ-incidence in the denosumab control group. In a time-to-ONJ-analysis, the curves of the sequential group and the denosumab control group were overlapping. In the sequential group, most of the ONJs occurred in the first year of denosumab exposure and in a matched control group analysis, with correction for median BRI-exposure, ONJ cases tend to occur earlier in the sequential group compared to ONJ cases in the bisphosphonates group. Conclusion: Cancer patients with bone metastases treated with BRIs seem to have a slightly higher risk of ONJ early after switching from bisphosphonates to denosumab compared to patients remaining on bisphosphonates. Nevertheless, based on the global ONJ-incidence, the switch from bisphosphonates to denosumab can be considered as safe as an equivalent exposure to denosumab from the start on.