Comparative safety and tolerability of approved PARP inhibitors in cancer: A systematic review and network meta-analysis

LIG1 Is a Synthetic Lethal Target in BRCA1 Mutant Cancers

Synthetic lethality approaches in BRCA1/2-mutated cancers have focused on PARP inhibitors, which are subject to high rates of innate or acquired resistance in patients. In this study, we used CRISPR/Cas9-based screening to identify DNA ligase I (LIG1) as a novel target for synthetic lethality in BRCA1-mutated cancers. Publicly available data supported LIG1 hyperdependence of BRCA1 mutant cells across a variety of breast and ovarian cancer cell lines. We used CRISPRn, CRISPRi, RNAi, and protein degradation to confirm the lethal effect of LIG1 inactivation at the DNA, RNA, and protein level in BRCA1 mutant cells in vitro. LIG1 inactivation resulted in viability loss across multiple BRCA1-mutated cell lines, whereas no effect was observed in BRCA1/2 wild-type cell lines, demonstrating target selectivity for the BRCA1 mutant context. On-target nature of the phenotype was demonstrated through rescue of viability with exogenous wild-type LIG1 cDNA. Next, we demonstrated a concentration-dependent relationship of LIG1 protein expression and BRCA1 mutant cell viability using a titratable, degradable LIG1 fusion protein. BRCA1 mutant viability required LIG1 catalytic activity, as catalytically dead mutant LIG1K568A failed to rescue viability loss caused by endogenous LIG1 depletion. LIG1 perturbation produced proportional increases in PAR staining in BRCA1 mutant cells, indicating a mechanism consistent with the function of LIG1 in sealing ssDNA nicks. Finally, we confirmed LIG1 hyperdependence in vivo using a xenograft model in which LIG1 loss resulted in tumor stasis in all mice. Our cumulative findings demonstrate that LIG1 is a promising synthetic lethal target for development in patients with BRCA1-mutant cancers.

Safety of niraparib-based regimens in patients with ovarian cancer: A systematic review and meta-analysis

BACKGROUND

Niraparib is approved as a maintenance treatment for ovarian cancer due to its potential to prolong progression-free survival. However, its widespread use is challenged by concerns about its safety profile. This systematic review and meta-analysis assesses the safety profile of niraparib in ovarian cancer treatment.

METHODS

A thorough literature search was done from inception to August 2024 using Embase, Cochrane Central Library, MEDLINE, and ClinicalTrials.gov. Randomized controlled trials (RCTs) and cohorts assessing the safety of niraparib in ovarian cancer were included. The primary outcome was adverse events. Review Manager was used to pool risk ratios (RR) with 95% confidence intervals (CIs) using the Mantel-Haenszel method for a random-effects analysis.

RESULTS

Eight studies were included in this meta-analysis, consisting of 4 Phase III RCTs and 4 observational studies with 2344 patients. Niraparib was associated with a higher risk of adverse events (RR = 1.05; 95 % CI: 1.02-1.09). Although subgroup analyses for the primary outcome did not show significant variations, secondary outcomes revealed notable findings. It also increases the risk of hematological toxicities, including thrombocytopenia (RR 2.75, 95 % CI 0.62-12.20), anemia (RR 1.74, 95 % CI: 1.06-2.86), and neutropenia (RR 1.63, 95 % CI: 1.04-2.54) with increased rates of treatment interruptions (RR 2.05, 95 % CI: 0.85-4.96) and dose reductions (RR = 2.35, 95 % CI: 0.89-6.17).

CONCLUSION

Our meta-analysis suggests that niraparib is associated with a tolerable safety profile in ovarian cancer maintenance treatment, with hematological toxicities being the primary concern. Further large-scale RCTs are essential to validate these findings and develop standardized safety protocols.

Overview of the epigenetic/cytotoxic dual-target inhibitors for cancer therapy

Epigenetic dysregulation plays a pivotal role in the initiation and progression of various cancers, influencing critical processes such as tumor growth, invasion, migration, survival, apoptosis, and angiogenesis. Consequently, targeting epigenetic pathways has emerged as a promising strategy for anticancer drug discovery in recent years. However, the clinical efficacy of epigenetic inhibitors, such as HDAC inhibitors, has been limited, often accompanied by resistance. To overcome these challenges, innovative therapeutic approaches are required, including the combination of epigenetic inhibitors with cytotoxic agents or the design of dual-acting inhibitors that target both epigenetic and cytotoxic pathways. In this review, we provide a comprehensive overview of the structures, biological functions and inhibitors of epigenetic regulators (such as HDAC, LSD1, PARP, and BET) and cytotoxic targets (including tubulin and topoisomerase). Furthermore, we discuss recent advancement of combination therapies and dual-target inhibitors that target both epigenetic and cytotoxic pathways, with a particular focus on recent advances, including rational drug design, pharmacodynamics, pharmacokinetics, and clinical applications.

Olaparib-associated toxicity in cancer patients: a systematic review and meta-analysis

PURPOSE

To investigate the characteristics of olaparib-associated adverse events (AEs) in cancer patients.

METHODS

Databases were searched for phase II and III randomized controlled trials (RCTs) involving olaparib treatment up to March 2024. A systematic assessment was performed.

RESULTS

Twenty-seven RCTs involving 9542 patients were included. This meta-analysis indicates that olaparib could significantly increase the risk of developing any all-grade (RR, 1.08; 95% CI, 1.03-1.13; p = 0.001) and high-grade (RR, 1.45; 95% CI, 1.19-1.77; p = 0.0003) AEs in cancer patients. Olaparib could increase the risk of dose reduction (RR, 3.00; 95% CI, 1.59-5.70; p = 0.0007) and treatment discontinuation (RR, 2.00; 95% CI, 1.28-3.14; p = 0.002). Hematologic toxicities and gastrointestinal toxicities commonly occur in patients receiving olaparib. Anemia, nausea, and fatigue were the most frequent AEs, with olaparib increasing the risk of both all-grade and high-grade occurrences of these events. Patients with longer treatment durations tend to have a higher risk of anemia. Patients with urinary system tumors tend to have a higher risk of nausea, while those with breast cancer tend to have a higher risk of fatigue. Olaparib maintenance therapy may be associated with a higher risk of fatigue. Olaparib could increase other AEs such as diarrhea, vomiting, decreased appetite, dyspepsia, dysgeusia, dizziness, headache, back pain, urinary tract infection, dyspnea, and cough.

CONCLUSION

Olaparib-containing therapy could increase the occurrence of specific AEs in patients with cancer. Clinicians should be aware of these risks and conduct regular monitoring.

Safety and hematological toxicities of PARP inhibitors in patients with cancer: a systematic review of randomized controlled trials and a pharmacovigilance analysis

INTRODUCTION

This study aimed to estimate the toxicities of PARP inhibitors (PARPis), based on randomized controlled trials (RCTs) and the FDA Adverse Event Reporting System (FAERS) database.

METHODS

Four electronic databases were searched from inception to 16 April 2024, for RCTs of approved PARPis. The primary and secondary outcomes were grade 3-5 adverse events (AEs) and grade 3-5 hematological AE, respectively. We conducted network meta-analyses to calculate the relative risks (RRs) and 95% confidence intervals (CIs) of outcomes. A disproportionality analysis was conducted to estimate the signals of hematological AEs associated with PARPis from the FAERS database.

RESULTS

Overall, 27 RCTs involving 11,067 patients with cancer were included. Olaparib had the best safety profile for any grade 3-5 AEs and hematological AEs among four approved PARPis. Olaparib did not increase the risk of thrombocytopenia (RR: 1.48; 95%CI: 0.64-3.39), but other PARPis did. Furthermore 14,780 hematological AE reports associated with PARPis were identified in the FAERS database, and all PARPis were associated with strong hematological AE signals. Hematological AEs mainly occurred within the first 3 months (80.84%) after PARPi initiation.

CONCLUSION

Olaparib had the best safety profile among five PARPis. PARPi-associated hematological AEs mainly occurred within the first 3 months.

REGISTRATION

PROSPERO (CRD42022385274).

Effective Radiosensitization of HNSCC Cell Lines by DNA-PKcs Inhibitor AZD7648 and PARP Inhibitors Talazoparib and Niraparib

(1) Head and neck squamous cell carcinoma (HNSCC) is common, while treatment is difficult, and mortality is high. Kinase inhibitors are promising to enhance the effects of radiotherapy. We compared the effects of the PARP inhibitors talazoparib and niraparib and that of the DNA-PKcs inhibitor AZD7648, combined with ionizing radiation. (2) Seven HNSCC cell lines, including Cal33, CLS-354, Detroit 562, HSC4, RPMI2650 (HPV-negative), UD-SCC-2 and UM-SCC-47 (HPV-positive), and two healthy fibroblast cell lines, SBLF8 and SBLF9, were studied. Flow cytometry was used to analyze apoptosis and necrosis induction (AnnexinV/7AAD) and cell cycle distribution (Hoechst). Cell inactivation was studied by the colony-forming assay. (3) AZD7648 had the strongest effects, radiosensitizing all HNSCC cell lines, almost always in a supra-additive manner. Talazoparib and niraparib were effective in both HPV-positive cell lines but only consistently in one and two HPV-negative cell lines, respectively. Healthy fibroblasts were not affected by any combined treatment in apoptosis and necrosis induction or G2/M-phase arrest. AZD7648 alone was not toxic to healthy fibroblasts, while the combination with ionizing radiation reduced clonogenicity. (4) In conclusion, talazoparib, niraparib and, most potently, AZD7648 could improve radiation therapy in HNSCC. Healthy fibroblasts tolerated AZD7648 alone extremely well, but irradiation-induced effects might occur. Our results justify in vivo studies.

Veliparib‑Induced Toxicity in Cancer Patients: A Systematic Review and Meta‑Analysis

In this study, we investigate the veliparib‑induced toxicity in cancer patients. Databases were searched for RCTs treated with veliparib. We found veliparib could increase the risk of hematologic and gastrointestinal toxicities. Anemia, neutropenia, thrombocytopenia, and nausea were the most common toxicities. Patients diagnosed with gastrointestinal tumors tend to have a higher risk of high-grade neutropenia; patients in the first-line setting tend to have a higher risk of high-grade anemia and neutropenia than those in the ≥ second line setting. Patients receiving higher dosage of veliparib tend to have a higher risk of all-grade anemia. Veliparib could also increase the risk of insomnia, myalgia, pneumonia, dyspnea, hyponatremia, and fatigue.

Synthetic Approaches to the New Drugs Approved During 2022

In 2022, 23 new small molecule chemical entities were approved as drugs by the United States FDA, European Union EMA, Japan PMDA, and China NMPA. This review describes the synthetic approach demonstrated on largest scale for each new drug based on patent or primary literature. The synthetic routes highlight practical methods to construct molecules, sometimes on the manufacturing scale, to access the new drugs. Ten additional drugs approved in 2021 and one approved in 2020 are included that were not covered in the previous year's review.

Predictive Value and Therapeutic Significance of Somatic BRCA Mutation in Solid Tumors

Ten percent of patients with breast cancer, and probably somewhat more in patients with ovarian cancer, have inherited germline DNA mutations in the breast and ovarian cancer genes BRCA1 and BRCA2. In the remaining cases, the disease is caused by acquired somatic genetic and epigenetic alterations. Targeted therapeutic agents, such as poly ADP-ribose polymerases (PARP) inhibitors (PARPi), have emerged in treating cancers associated with germline BRCA mutations since 2014. The first PARPi was FDA-approved initially for ovarian cancer patients with germline BRCA mutations. Deleterious variants in the BRCA1/BRCA2 genes and homologous recombination deficiency status have been strong predictors of response to PARPi in a few solid tumors since then. However, the relevance of somatic BRCA mutations is less clear. Somatic BRCA-mutated tumors might also respond to this new class of therapeutics. Although the related literature is often controversial, recently published case reports and/or randomized studies demonstrated the effectiveness of PARPi in treating patients with somatic BRCA mutations. The aim of this review is to summarize the predictive role of somatic BRCA mutations and to provide further assistance for clinicians with the identification of patients who could potentially benefit from PARPi.

Optimal reconstruction methods after distal gastrectomy for gastric cancer: a protocol for a systematic review and network meta-analysis update

BACKGROUND

Distal gastrectomy (DG) is a commonly used surgical procedure for gastric cancer (GC), with three reconstruction methods available: Billroth I, Billroth II, and Roux-en-Y. In 2018, our team published a systematic review to provide guidance for clinical practice on the optimal reconstruction method after DG for GC. However, since then, new evidence from several randomized controlled trials (RCTs) has emerged, prompting us to conduct an updated systematic review and network meta-analysis to provide the latest comparative estimates of the efficacy and safety of the three reconstruction methods after DG for GC.

METHOD

This systematic review and network meta-analysis update followed the PRISMA-P guidelines and will include a search of PubMed, Embase, and the Cochrane Library for RCTs comparing the outcomes of Billroth I, Billroth II, or Roux-en-Y reconstruction after DG for patients with GC. Two independent reviewers will screen the titles and abstracts based on predefined eligibility criteria, and two reviewers will assess the full texts of relevant studies. The Bayesian network meta-analysis will evaluate various outcomes, including quality of life after surgery, anastomotic leakage within 30 days after surgery, operation time, intraoperative blood loss, major postoperative complications within 30 days after surgery, incidence and severity of bile reflux, and loss of body weight from baseline.

ETHICS AND DISSEMINATION

The review does not require ethical approval. The findings of the review will be disseminated through publication in an academic journal, presentations at conferences, and various media outlets.

INPLASY REGISTRATION NUMBER

INPLASY2021100060.

A Bifunctional PARP-HDAC Inhibitor with Activity in Ewing Sarcoma

PURPOSE

Histone deacetylase (HDAC) inhibition has been shown to induce pharmacologic "BRCAness" in cancer cells with proficient DNA repair activity. This provides a rationale for exploring combination treatments with HDAC and PARP inhibition in cancer types that are insensitive to single-agent PARP inhibitors (PARPi). Here, we report the concept and characterization of a novel bifunctional PARPi (kt-3283) with dual activity toward PARP1/2 and HDAC enzymes in Ewing sarcoma cells.

EXPERIMENTAL DESIGN

Inhibition of PARP1/2 and HDAC was measured using PARP1/2, HDAC activity, and PAR formation assays. Cytotoxicity was assessed by IncuCyte live cell imaging, CellTiter-Glo, and spheroid assays. Cell-cycle profiles were determined using propidium iodide staining and flow cytometry. DNA damage was examined by γH2AX expression and comet assay. Inhibition of metastatic potential by kt-3283 was evaluated via ex vivo pulmonary metastasis assay (PuMA).

RESULTS

Compared with FDA-approved PARP (olaparib) and HDAC (vorinostat) inhibitors, kt-3283 displayed enhanced cytotoxicity in Ewing sarcoma models. The kt-3283-induced cytotoxicity was associated with strong S and G2-M cell-cycle arrest in nanomolar concentration range and elevated DNA damage as assessed by γH2AX tracking and comet assays. In three-dimensional spheroid models of Ewing sarcoma, kt-3283 showed efficacy in lower concentrations than olaparib and vorinostat, and kt-3283 inhibited colonization of Ewing sarcoma cells in the ex vivo PuMA model.

CONCLUSIONS

Our data demonstrate the preclinical justification for studying the benefit of dual PARP and HDAC inhibition in the treatment of Ewing sarcoma in a clinical trial and provides proof-of-concept for a bifunctional single-molecule therapeutic strategy.

Homologous Recombination Deficiency (HRD) in Cutaneous Oncology

Skin cancers, including basal cell carcinoma (BCC), cutaneous squamous cell carcinoma (SCC), and melanoma, are the most common malignancies in the United States. Loss of DNA repair pathways in the skin plays a significant role in tumorigenesis. In recent years, targeting DNA repair pathways, particularly homologous recombination deficiency (HRD), has emerged as a potential therapeutic approach in cutaneous malignancies. This review provides an overview of DNA damage and repair pathways, with a focus on HRD, and discusses major advances in targeting these pathways in skin cancers. Poly(ADP-ribose) polymerase (PARP) inhibitors have been developed to exploit HRD in cancer cells. PARP inhibitors disrupt DNA repair mechanisms by inhibiting PARP enzymatic activity, leading to the accumulation of DNA damage and cell death. The concept of synthetic lethality has been demonstrated in HR-deficient cells, such as those with BRCA1/2 mutations, which exhibit increased sensitivity to PARP inhibitors. HRD assessment methods, including genomic scars, RAD51 foci formation, functional assays, and BRCA1/2 mutation analysis, are discussed as tools for identifying patients who may benefit from PARP inhibitor therapy. Furthermore, HRD has been implicated in the response to immunotherapy, and the combination of PARP inhibitors with immunotherapy has shown promising results. The frequency of HRD in melanoma ranges from 18% to 57%, and studies investigating the use of PARP inhibitors as monotherapy in melanoma are limited. Further research is warranted to explore the potential of PARP inhibition in melanoma treatment.

Case report: A de novo ERBB3 mutation develops in a gallbladder cancer patient carrying BRCA1 mutation after effective treatment with olaparib

BACKGROUND

Gallbladder cancer (GBC) is highly lethal and resistant to most chemotherapeutic drugs. GBC was reported to carry multiple genetic mutations such as TP53, K-RAS, and ERBB2/3. Here, we unexpectedly identified a patient with GBC harboring germline BRCA1 p.Arg1325Lys heterozygous mutation. We sought to determine if olaparib, the poly ADP-ribose polymerase inhibitor (PARPi) commonly treated for BRCA mutation, can inhibit cancer development via a therapeutic trial on this patient.

CASE PRESENTATION

The patient received GBC R0 resection after an 8-week olaparib treatment. After surgery and 6-month follow-up treatment with olaparib, the patient's blood carbohydrate antigen 19-9 (CA19-9) level declined from 328 to 23.6 U/ml. No recurrence in CT scanning was observed, indicating a disease-free survival of 6 months with conventional therapy. Two months later, CT examination and CA19-9 level showed cancer relapse. A blood biopsy revealed a new ERBB3 p.Gly337Arg mutation. GBC cell lines ectopically expressing BRCA1 p.Arg1325Lys together with ERBB3 p.Gly337Arg mutations were challenged with olaparib and/or afatinib, an ERBB2/3 inhibitor. The dual mutation cells were more responsive to the combined olaparib with afatinib than a single drug in the cell proliferation assay.

CONCLUSION

Olaparib is effective in a GBC patient with a BRAC1 mutation. The efficacy of olaparib and afatinib in both cultured BRAC1 and ERBB3 mutation cell lines suggests that a combined regimen targeting BRCA1/2 and ERBB2/3 mutations may be an optimal strategy to treat GBC patients who carry both gene mutations.

Attenuation of Tumor Burden in Response to Rucaparib in Lung Adenocarcinoma: The Contribution of Oxidative Stress, Apoptosis, and DNA Damage

In cancer, overactivation of poly (ADPribose) polymerases (PARP) plays a relevant role in DNA repair. We hypothesized that treatment with the PARP inhibitor rucaparib may reduce tumor burden via several biological mechanisms (apoptosis and oxidative stress) in mice. In lung tumors (LP07 lung adenocarcinoma) of mice treated/non-treated (control animals) with PARP inhibitor (rucaparib,150 mg/kg body weight/24 h for 20 day), PARP activity and expression, DNA damage, apoptotic nuclei, cell proliferation, and redox balance were measured using immunoblotting and immunohistochemistry. In lung tumors of rucaparib-treated mice compared to non-treated animals, tumor burden, PARP activity, and cell proliferation decreased, while DNA damage, TUNEL-positive nuclei, protein oxidation, and superoxide dismutase content (SOD)2 increased. In this experiment on lung adenocarcinoma, the pharmacological PARP inhibitor rucaparib elicited a significant improvement in tumor size, probably through a reduction in cell proliferation as a result of a rise in DNA damage and apoptosis. Oxidative stress and SOD2 also increased in response to treatment with rucaparib within the tumor cells of the treated mice. These results put the line forward to the contribution of PARP inhibitors to reduced tumor burden in lung adenocarcinoma. The potential implications of these findings should be tested in clinical settings of patients with lung tumors.

Differences in Durability of PARP Inhibition by Clinically Approved PARP Inhibitors: Implications for Combinations and Scheduling

Six PARP inhibitors (PARPi) are approved for cancer therapy as monotherapy agents in daily or twice-daily continuous dosing schedules to maintain the necessary continuous suppression of PARP activity. Continuous PARP inhibition is required for single-agent anticancer activity. To investigate if such intense schedules are necessary, we determined the durability of PARP inhibition up to 72 h after a 1 h pulse of 1 µM of five of the approved PARPi, rucaparib, olaparib, niraparib, talazoparib and pamiparib, in IGROV-1 and ES-2 (human ovarian cancer) cells. Rucaparib caused the most persistent inhibition of PARP activity when maintained at ≥75% at 72 h after drug withdrawal in both IGROV-1 and ES-2 cells, but inhibition was more rapidly lost with the other PARPi. PARPi are also under clinical investigation with ATR inhibitors, and thus, we evaluated the implications for scheduling with an ATR inhibitor (VE-821). Rucaparib enhanced VE-821 cytotoxicity in co-exposure, sequential and delayed (24 h drug-free) schedules in IGROV-1 and ES-2 cells. Olaparib and niraparib enhanced VE-821 cytotoxicity only in co-exposed cells and not in sequential exposures. These data have clinical implications for the scheduling of PARPi as a monotherapy and in combination with ATR inhibitors and other cytotoxic drugs.

The Role of PARP Inhibitors in Patients with Primary Malignant Central Nervous System Tumors

OPINION STATEMENT

Primary malignant central nervous (CNS) tumors are a devastating group of diseases with urgent need for improved treatment options. Surgery, radiation, and cytotoxic chemotherapy remain the primary standard treatment modalities, with molecularly targeted therapies having proven efficacy in only small subsets of cases. Poly(ADP-ribose) polymerase (PARP) inhibitors, which have had immense success in the treatment of extracranial cancers with homologous recombination deficiency (HRD), are emerging as a potential targeted treatment for various CNS tumors. Although few primary CNS tumors display canonical BRCA gene defects, preclinical evidence suggests that PARP inhibitors may benefit certain CNS tumors with functional HRD or elevated replication stress. In addition, other preclinical studies indicate that PARP inhibitors may synergize with standard therapies used for CNS tumors including radiation and alkylating agents and may prevent or overcome drug resistance. Thus far, initial clinical trials with early-generation PARP inhibitors, typically as monotherapy or in the absence of selective biomarkers, have shown limited efficacy. However, the scientific rationale remains promising, and many clinical trials are ongoing, including investigations of more CNS penetrant or more potent inhibitors and of combination therapy with immune checkpoint inhibitors. Early phase trials are also critically focusing on determining active drug CNS penetration and identifying biomarkers of therapy response. In this review, we will discuss the preclinical evidence supporting use of PARP inhibitors in primary CNS tumors and clinical trial results to date, highlighting ongoing trials and future directions in the field that may yield important findings and potentially impact the treatment of these devastating malignancies in the coming years.

Tailored therapy for Helicobacter pylori eradication: A systematic review and meta-analysis

Background: Due to an increase in drug resistance, the eradication rate of H. pylori with empirical therapy has declined. Tailored therapy has been proposed as an alternative to standard empirical treatments. The necessity of personalized eradication therapy remains unclear. The aim of this study was to determine whether tailored therapy is superior to empirical therapy for H. pylori infection. Methods: We searched for eligible randomized controlled trials in the PubMed, Embase (Ovid), Wanfang, and Cochrane Central Register of Controlled Trials databases up to 10 December 2021. A random effects model comparing pooled relative risks (RRs) with 95% confidence intervals (CIs) was applied in the meta-analysis. Results: Twenty-one studies were included in the meta-analysis. In the first-line treatment, tailored therapy was more effective than empirical therapy (RR, 1.14 [95% CI, 1.08-1.21], I2 = 72.2%). In the second-line therapy setting, the results did not reveal significant differences between the two treatments (RR, 1.05 [95% CI, 0.84-1.30], I2 = 80.6%). A similar result was observed in mixed second- and third-line treatments (RR, 1.03 [95% CI, 0.96-1.11], I2 = 0.0%). Regarding adverse events, no significant differences were found between the two treatments (RR, 0.90 [95% CI, 0.80-1.01], I2 = 35.7%). Most of the results were highly heterogeneous. Conclusion: A tailored approach might provide a better eradication rate than empirical methods in first-line treatment. There might be no obvious advantage in second-line or mixed second- and third-line treatments third-line treatment. Due to the high heterogeneity, the results should be interpreted with caution. Further clinical studies are needed and justified.

Radiotherapy in the Management of Gastrointestinal Stromal Tumors: A Systematic Review

Gastrointestinal stromal tumors (GISTs) are considered insensitive to radiotherapy. However, a growing number of case reports and case series have shown that some lesions treated by radiotherapy achieved an objective response. The aim of the study was to perform a systematic review of all reported cases, case series, and clinical studies of GISTs treated with radiotherapy to reevaluate the role of radiotherapy in GISTs. A systematic search of the English-written literature was conducted using PubMed, Web of Science, and Embase databases. Overall, 41 articles describing 112 patients were retrieved. The included articles were of low to moderate quality. Bone was the most common site treated by radiotherapy, followed by the abdomen. In order to exclude the influence of effective tyrosine kinase inhibitors (TKIs), a subgroup analysis was conducted on whether and which TKIs were concurrently applied with radiotherapy. Results showed that radiotherapy alone or combined with resistant TKIs could help achieve objective response in selected patients with advanced or metastatic GISTs; however, survival benefits were not observed in the included studies. Pain was the most common symptom in symptomatic GISTs, followed by neurological dysfunction and bleeding. The symptom palliation rate was 78.6% after excluding the influence of effective TKIs. The adverse reactions were mainly graded 1-2. Radiotherapy was generally well-tolerated. Overall, radiotherapy may relieve symptoms for GIST patients with advanced or metastatic lesions and even help achieve objective response in selected patients without significantly reducing the quality of life. In addition to bone metastases, fixed abdominal lesions may be treated by radiotherapy. Publication bias and insufficient quality of included studies were the main limitations in this review. Further clinical studies are needed and justified.

Open and minimally invasive surgery for gastrointestinal stromal tumours: a systematic review and network meta-analysis protocol

INTRODUCTION

Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal tumours of the digestive system, and complete resection is the only way to provide a radical cure for resectable GISTs. Open surgery and minimally invasive approaches, including laparoscopy, robotic surgery and endoscopy, consist of the mainstream GIST resection. However, there is still a lack of evidence regarding which surgical outcomes and long-term prognosis would be better. Thus, we are planning to conduct a network meta-analysis and systematic review aiming to determine the comparative effectiveness among laparotomy, laparoscopy, endoscopy, robotic surgery, and laparoscopic and endoscopic cooperative surgery in GISTs.

METHOD AND ANALYSIS

PubMed, EMBASE, the Cochrane Library and Web of Science will be searched for published studies to identify the proper literature comparing open resection, laparoscopy, endoscopy, robotic surgery, and laparoscopic and endoscopic cooperative surgery for resecting GISTs from inception to February 2021. Randomised controlled trials (RCTs) and non-randomised studies comparing at least two different interventions for GIST resection will be included. RCTs and non-randomised studies will be synthesised and analysed separately. Bayesian network meta-analysis will be performed to compare the surgical outcomes and long-term prognosis among the resection methods above. The included studies will be divided into several subgroups according to tumour location and size for further analysis. Sensitivity analysis will be performed to identify and explain heterogeneity to make our results robust. Meta-regression will serve as a supplementary method if data are available. The quality of evidence will be evaluated by the Grading of Recommendations, Assessment, Development and Evaluation.

ETHICS AND DISSEMINATION

No ethical approval is required for this network meta-analysis, as it is based on already published data. The findings of the review will be published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42021237892.

The role of PARP inhibitors in gastrointestinal cancers

The use of BReast CAncer (BRCA) mutations as biomarkers for sensitivity to DNA damage response (DDR) targeted drugs and platinum agents is well documented in breast and gynaecological cancers. More recently the successful use DDR targeted therapies including poly (ADP-ribose) polymerases (PARP) inhibitors has been shown to extend to other germline and somatic deficiencies within the homologous recombination (HR) pathway^1-3. Gastrointestinal (GI) cancers are lagging behind other tumour types when it comes to personalising treatment with targeted therapies. Current methods of identifying PARP-inhibitor sensitivity in gastrointestinal cancers are based on analogies from other cancer types despite there being a lack of uniformity in determining HR status between tumour types. There is an urgent clinical need to better understand the treatment implications of DDR alterations in gastrointestinal cancers. We have reviewed PARP-inhibitor use in pancreatic, gastroesophageal, hepatobiliary and colorectal cancers and explored HRD as a biomarker for sensitivity to PARP-inhibitors.

Case Report and Literature Review: Catastrophic Embolism Following Cosmetic Injection of Autologous Fat in the Face

Injection of autologous fat on the face is a commonly performed procedure in plastic surgery. However, it can lead to rare but devastating complications due to fat embolism. In this study, we presented two cases of cerebral infarction and/or sudden vision loss after cosmetic injections of autologous fat on the face. Two women underwent injections into the temporal and frontal areas, respectively. In case 1, the patient underwent decompressive craniectomy as her condition deteriorated continuously and died. In case 2, the patient's vision had not improved at the 3-month follow-up visit. Imaging examinations showed occlusion of the right external carotid artery in case 1, and multiple retinal arterioles were segmentally occluded in case 2. We also screened relevant studies via a systematic search of PubMed (last updated on May 9, 2020) and performed a narrative review due to the significant heterogeneity between the studies. To prevent this catastrophic event, the autologous fat injection should be performed carefully. If embolization does occur, early diagnosis and timely treatment may help improve functional outcomes.

Surgical resection for patients with recurrent or metastatic gastrointestinal stromal tumors: a protocol for a systematic review and meta-analysis update

BACKGROUND

There are limited data on the clinical benefits of adding surgical resection in patients with recurrent or metastatic gastrointestinal stromal tumors (GISTs). This protocol outlines the planned scope and methods for a systematic review and meta-analysis update that will compare the clinical outcomes of surgical resection combined with tyrosine kinase inhibitor (TKI) with TKI treatment alone in patients with recurrent or metastatic GISTs.

METHODS

This review will update a previously published systematic review by our team. This protocol is presented in accordance with the PRISMA-P guideline. PubMed, Embase, and Cochrane Central Register of Controlled Trials will be systematically searched and supplemented by a secondary screening of the references of all included studies. We will include randomized controlled trials (RCTs) and non-randomized studies (NRS) in this review update. The outcomes evaluated will be overall survival and progression-free survival. Two reviewers will independently screen and select studies, extract data from the included studies, and assess the risk of bias of the included studies. Data extracted from RCTs and NRS will be analysed and reported separately. Preplanned subgroup analyses and sensitivity analyses are detailed within this protocol. The strength of the body of evidence will be assessed using GRADE.

DISCUSSION

This systematic review and meta-analysis update will provide a current assessment of the evidence for the role of surgery in patients with recurrent or metastatic advanced GISTs. These findings will be used by the Chinese Society of Clinical Oncology (CSCO) GIST guideline recommendations on surgical treatment for recurrent or metastatic advanced GIST patients in China.

SYSTEMATIC REVIEW REGISTRATION

This protocol was prospectively registered in the Open Science Framework Registry ( https://osf.io/xus7m ).