A case of placental site trophoblastic tumor managed in a low resource setting.

Placental trophoblastic site tumor (PSTT) is a rare type of gestational trophoblastic neoplasia (GTN). PSTT has a higher mortality than other types of gestational trophoblastic disease (GTD), with a rate of 16.1%, due to its relatively unpredictable behavior and reduced response to chemotherapy. Its diagnostic and management are very challenging in Low resources settings particularity in Haiti where MRI, PET Scan and IHC are not available. Further, the follow-up is very difficult because of social, political, and economic issues limiting the capacity of our patients to be present at all scheduled visits. No case of PSTT has been publicly described yet the Haitian experience in the literature in the management of such case compared to the developed world. We present a case of PSTT successfully diagnosed and managed at Mirebalais University Hospital (MUH) in Haiti with the support of telepathology and intentional partners while highlighting the difference that we observed compare to the developed world.

The Rare of the Rarest: Placental Site Trophoblastic Tumor, Epithelioid Trophoblastic Tumor, Atypical Placental Site Nodule.

BACKGROUND: Epithelioid Trophoblastic Tumor (ETT) and Placental Site Trophoblastic Tumor (PSTT) are two of the rarest GTNs that share certain features at diagnosis and management. Atypical Placental Site Nodule (APSN) is a relatively new entity considered as a premalignant lesion. OBJECTIVES AND METHODS: The aim of this review was to summarize the main characteristics of each of these entities, their diagnostic features, and their treatment's standard of care including fertility-sparing treatments. OUTCOME: This study provides a thorough review of ETT, PSTT, and APSN. CONCLUSIONS: The reader will gain an insight view of these rare tumors arising from the intermediate trophoblast.

Ovarian non-gestational placental site trophoblastic tumor with lung metastasis: further evidence for a distinct category of trophoblastic neoplasm.

We previously described a series of cases which characterize a distinct group of primary ovarian placental site trophoblastic tumor (PSTT) and epithelioid trophoblastic tumor (ETT) as a non-gestational set consistent with germ cell type/origin. Here we report a new case of ovarian non-gestational PSTT. The patient was a 13 year-old young female admitted for a spontaneous pneumothorax of the left lung. The pathology of lung wedge excision specimen demonstrated metastatic PSTT and ovarian biopsy showed atypical intermediate trophoblastic proliferation which was found to be PSTT in the subsequent salpingo-oophorectomy specimen. In the ovary, the tumor was composed of singly dispersed or small clusters of predominantly mononuclear cells and rare multinucleated cells extensively infiltrating the ovarian parenchyma, tubal mucosa, and paraovarian/paratubal soft tissue. A minor component of mature cystic teratoma (less than 5% of total tumor volume) was present. Immunohistochemically, the neoplastic cells of main tumor were diffusely immunoreactive for hPL, Gata3 and AE1/AE3, and had only rare hCG-positive or p63-positive cells. The morphology and immunohistochemical results support a PSTT. Molecular genotyping revealed an identical genotype pattern between the normal lung tissue and the metastatic PSTT, indicating its non-gestational nature of germ cell type/origin. This case represents the first case of such tumor with distant (lung) metastasis. This case also provides further evidence to support our recommendation that primary ovarian non-gestational intermediate trophoblastic tumors of germ cell type/origin, including PSTT and ETT, should be formally recognized in classification systems.

Placental-site trophoblastic tumor with bone metastasis: A diagnostic and therapeutic challenge.

Placental-site trophoblastic tumor (PSTT) is a rare pathological entity included in the spectrum of gestational trophoblastic neoplasia (GTN). It is a neoplasia with metastatic potential that, once metastasized, has poor prognosis because the tumor tends to be less sensitive to chemotherapy. We present a rare case of gestational trophoblastic neoplasia, in which hysterectomy for persistent gestational trophoblastic disease after hydatidiform mole, revealed a primary PSTT in the uterus. Subsequently, a slight persistent elevation of the beta fraction of human chorionic gonadotropin hormone (B-hCG) during follow-up revealed the presence of bone metastases. This location is not usual from this tumor, being even more rare the case of PSTT with isolated bone metastases. Metastasic foci were only identified with PET-CT since the usual diagnostic resources were not able to do it. Finally, it is also remarkable in our case that the treatment required the confluence of chemotherapy together with immunotherapy to achieve a favorable response.

Gestational trophoblastic neoplasia of intermediate trophoblasts: Epithelioid trophoblastic tumor and placental site trophoblastic tumor, a study of morphologic, immunohistochemical, and next generation sequencing.

Objective: Gestational trophoblastic tumors are very rare neoplasms. We determined the distinctive morphological, immunohistochemical, and clinical features of placental site trophoblastic tumors (PSTT) and epithelioid trophoblastic tumors (ETT) in our cohort. Materials and Methods: Nine cases of PSTT and four cases of ETT were retrieved from the archives. Histomorphologic, immunohistochemical, and clinical features were noted. A molecular study was performed on one PSTT and one ETT case using next-generation sequencing. Results: While the nodular pattern, geographic necrosis, and extracellular eosinophilic globules were peculiar to ETTs, vessel wall affinity, marked pleomorphism, intranuclear pseudoinclusion, spindle tumor cell, and vacuolar degeneration were more specific for PSTTs in our series. An immunohistochemical panel of p63, hPL, and CD146 were helpful for the exact typing of the tumor. p63 positivity supports the ETT and diffuse staining of hPL and CD146 supports the PSTT diagnosis. Three of the patients with metastatic disease (lung and brain metastasis) except one have a high mitotic count (12 and 8) and a long interval between (8 and 10 years) antecedent pregnancy and diagnosis. While KIT and TP53 mutations were observed only in PSTT, amino acid changes in KDR, APC, and SMAD4 genes were detected both in the ETT and PSTT cases. Conclusion: In the prediction of metastasis, the long intervals between antecedent pregnancy and diagnosis, deep myometrial invasion, mitotic count, and Ki67 proliferation index were involved rather than other histomorphological parameters, but none of the parameters is an absolute predictor of the metastasis.

Management of trophoblastic tumors : review of evidence, current practice, and future directions.

INTRODUCTION: Gestational trophoblastic neoplasia (GTN) is a group of rare tumors characterized by abnormal trophoblastic proliferation following pregnancy including invasive moles, choriocarcinomas, and intermediate trophoblastic tumors (ITT). Although the treatment and follow-up of GTN has been heterogeneous, globally the emergence of expert networks has helped to harmonize its management. AREAS COVERED: We provide an overview of the current knowledge, diagnosis, and management strategies in GTN and discuss innovative therapeutic options under investigation. While chemotherapy has been the historical backbone of GTN treatment, promising drugs such as immune checkpoint inhibitors targeting the PD-1/PD-L1 pathway and anti-angiogenic tyrosine kinase inhibitors are currently being investigated remodeling the therapeutical landscape of trophoblastic tumors. EXPERT OPINION: Chemotherapy regimens for GTN have potential long-term effects on fertility and quality of life, making innovative and less toxic therapeutic approaches necessary. Immune checkpoint inhibitors have shown promise in reversing immune tolerance in GTN and have been evaluated in several trials. However, immunotherapy is associated with rare but life-threatening adverse events and evidence of immune-related infertility in mice, highlighting the need for further research and careful consideration of its use. Innovative biomarkers could help personalize GTN treatments and reduce chemotherapy burden in some patients.

Placental site trophoblastic tumor (PSTT): a case report and review of the literature.

Placental site trophoblastic tumor (PSTT), also known as atypical choriocarcinoma, syncytioma, chorioepitheliosis or trophoblastic pseudotumor, is a rare gestational trophoblastic disease (0.25-5% of all trophoblastic tumors) and it is composed by neoplastic proliferation of intermediate trophoblasts at placental implantation site. It consists of aggregates or sheets of large, polyhedral to round, predominantly mononucleated cells with a characteristic vascular and myometrial invasion. Main differential diagnoses are gestational choriocarcinoma (GC) and epitelioid trophoblastic tumor (ETT). We present a case of PSTT in a 25-year-old woman. Neoplastic cells showed moderate/high nuclear pleomorphism, abundant amphophilic, eosinophilic and clear cytoplasm, numerous mitotic figures (10 mitoses/10 HPF), and myometrial invasion. Other features are necrosis, vascular invasion with replacement of myometrial vessels by tumor cells and hemorrhage. The patient showed typical low serum ß-hCG levels and high serum humane placental lactogen (hPL) levels.

Retrospective analysis of clinical features and fertility outcomes with fertility-sparing treatment of placental site trophoblastic tumor.

OBJECTIVE: To analyze the methods, feasibility, efficiency, and fertility outcomes of fertility-sparing treatment for patients with placental site trophoblastic tumor (PSTT). METHODS: Clinical data of patients diagnosed with PSTT between April 1998 and April 2020 from Peking Union Medical College Hospital (PUMCH) were retrospectively collected. The clinical features, treatment, and outcomes of patients received fertility-sparing treatment were analyzed and compared with patients suffered hysterectomy. RESULTS: In total, 126 patients were included in the study and 29 of them received fertility-sparing treatment. Besides significantly younger age and lower proportion of antecedent term delivery were seen in fertility-sparing group than hysterectomy group, no significant differences were observed in stage, serum ß-hCG level, or interval from antecedent pregnancy between the two groups. Conservative surgery was selected individualized and none of them suffered salvage hysterectomy. Patients with clinical or pathological high-risk factors received adjuvant chemotherapy, yet the fertility-sparing treatment did not significantly lengthen chemotherapy duration. All patients in fertility-sparing group achieved complete remission without relapse after 36 to 176 months of follow-up and had sixteen healthy term delivery more than one year after the treatment. CONCLUSIONS: Fertility-sparing treatment for PSTT can be considered for young patients with localized uterine lesions who strongly desire to preserve their fertility potential. With individualized conservative surgery and selected adjuvant chemotherapy, fertility-sparing treatment will not influence the risk of relapse or overall survival and patients will achieve favorable pregnancy and live birth outcomes.

Gestational trophoblastic disease: an update.

Gestational trophoblastic diseases (GTD) encompass a spectrum of rare pre-malignant and malignant entities originating from trophoblastic tissue. This updated review will highlight important radiological features, pathology and classification, and provide insight into the clinical management of these uncommon disorders. There is a wide geographic variation with the incidence of hydatidiform mole varying between 0.57 and 2 per 1000 pregnancies. The use of ultrasound (US) in the management of early pregnancy symptoms and complications has positively impacted the earlier detection of these diseases and resulted in diminished morbidity. Additional imaging modalities are reserved for problem solving or assessment of pulmonary manifestations of molar pregnancy. Having an awareness of their pleomorphic sonographic presentation and additional pathology that can mimic GTD is critical to avoiding pitfalls. Histologic and molecular analysis further aids in differential diagnosis. Gestational trophoblastic neoplasia (GTN) is inclusive of all malignant GTDs, and arises after 20% of molar pregnancies but can also be seen with non-molar gestations. Biochemical monitoring with human chorionic gonadotrophin is imperative for ongoing monitoring and surveillance and allows early detection of this entity. Doppler US is used for confirmation of diagnosis with magnetic resonance imaging (MRI) reserved for problem solving or assessment of myometrial invasion. This is of heightened relevance in patients undergoing surgical management. Cross sectional imaging is reserved for patients in the setting of GTN for the purposes of staging, prognostication and in the setting of recurrent disease. This may require a combination of computed tomography, MRI and positron emission tomography. Doppler US can provide insight into chemotherapeutic response/predict resistance in patients with GTN. As our understanding of these disorders evolves, there has been maturation in management options with a shift from traditional chemotherapy to innovative immunotherapy, particularly in the setting of resistant or high-risk disease.

Gestational Trophoblastic Disease: Contemporary Diagnostic Approach.

Pathologic diagnosis of gestational trophoblastic disease (GTD)-hydatidiform moles and gestational trophoblastic neoplasms-underwent a major shift in the past decade from morphology-based recognition to precise molecular genetic classification of entities, which also allows for prognostic stratification of molar gestations. This article highlights these recent advances and their integration into the routine pathology practice. The traditional gross and histomorphologic features of each entity are also reviewed with special focus on differential diagnoses and their clinical implications.

Gestational trophoblastic disease- rare, sometimes dramatic, and what we know so far.

Gestational trophoblastic disease (GTD) is a heterogeneous group of lesions that are characterized by the abnormal proliferation of the trophoblast. Morphology, behavior and clinical significance vary tremendously and range from benign, non-neoplastic lesions that cause sometimes dysfunctional uterine bleeding to aggressive, highly, malignant tumors. The recently updated 2020 World Health Organization (WHO) Classification of Female Genital Tumors divides GTD in molar pregnancies/ hydatidiform moles, gestational trophoblastic neoplasms, tumor-like lesions and abnormal (nonmolar) villous lesions. In this article we review the typical clinical presentations of GTDs, their histopathologic features, contributing immunohistochemical stains and current diagnostic criteria. We discuss novel insights in the proposed pathogenesis, newly proposed entities and advances in ancillary diagnostic techniques and their relevance to the histopathologic diagnosis of GTD. Additionally we briefly review current treatment options, prognosis and prognostic factors of GTDs.

Outcomes and prognostic factors of placental-site trophoblastic tumor: a retrospective study of 58 cases.

PURPOSE: Our goal was to assess the outcomes and explore the prognostic factors for patients with placental-site trophoblastic tumor (PSTT) through this retrospective analysis. METHODS: 2043 patients with gestational trophoblastic neoplasia (GTN) were registered at two tertiary hospitals between January 2003 and March 2021, of whom 58 (2.8%) were diagnosed with PSTT. We retrospectively analyzed the clinico-pathological characteristics, treatments, outcomes and prognostic factors. RESULTS: Only 4 patients died and 5 patients experienced a recurrence. Patients (n = 49) with stage I disease had a favorable prognosis, surgery with (n = 21) or without (n = 28) chemotherapy made no significant difference in overall survival (OS) (p = 0.251) or disease-free survival (DFS) (p = 0.425). 3 patients with stage I had fertility preserving surgery and successful pregnancy was achieved in 2 of them. The outcome of patients with advanced disease was poor. Univariate analysis revealed serum ß-hCG levels at diagnosis, FIGO stage IV and metastatic disease were significant predictors of both overall survival and disease-free survival. However, multivariate analysis indicated stage IV was the only significant independent predictor of adverse OS, while metastatic disease was the only significant independent predictor of adverse DFS. CONCLUSION: Surgery alone is sufficient for patients with stage I disease without high-risk factors. The prognosis of patients with advanced stage disease remains poor. Stage IV and metastatic disease were the most critical risk factors.

Expression profiling of lncRNAs and mRNAs in placental site trophoblastic tumor (PSTT) by microarray.

As a rare type of gestational trophoblastic disease, placental site trophoblastic tumor (PSTT) is originated from intermediate trophoblast cells. Long noncoding RNAs (lncRNAs) regulate numerous biological process. However, the role of lncRNAs in PSTT remains poorly understood. In the present study, expression levels of lncRNAs and mRNAs in four human PSTT tissues and four normal placental villi were investigated. The results of microarray were validated by the reverse transcription and quantitative real-time polymerase reaction (RT-qPCR) and immunohistochemistry analyses. Furthermore, GO and KEGG pathway analyses were performed to identify the underlying biological processes and signaling pathways of aberrantly expressed lncRNAs and mRNAs. We also conducted the coding-non-coding gene co-expression (CNC) network to explore the interaction of altered lncRNAs and mRNAs. In total, we identified 1247 up-regulated lncRNAs and 1013 down-regulated lncRNAs as well as 828 up-regulated mRNAs and 1393 down-regulated mRNAs in PSTT tissues compared to normal villi (fold change ≥ 2.0, p < 0.05). GO analysis showed that mitochondrion was the most significantly down-regulated GO term, and immune response was the most significantly up-regulated term. A CNC network profile based on six confirmed lncRNAs (NONHSAT114519, NR_103711, NONHSAT003875, NONHSAT136587, NONHSAT134431, NONHSAT102500) as well as 354 mRNAs was composed of 497 edges. GO and KEGG analyses indicated that interacted mRNAs were enriched in the signal-recognition particle (SRP)-dependent cotranslational protein targeting to membrane and Ribosome pathway. It contributes to expand the understanding of the aberrant lncRNAs and mRNAs profiles of PSTT, which may be helpful for the exploration of new diagnosis and treatment of PSTT.

Diagnosis and management of gestational trophoblastic disease: 2021 update.

Gestational trophoblastic disease (GTD) arises from abnormal placenta and is composed of a spectrum of premalignant to malignant disorders. Changes in epidemiology of GTD have been noted in various countries. In addition to histology, molecular genetic studies can help in the diagnostic pathway. Earlier detection of molar pregnancy by ultrasound has resulted in changes in clinical presentation and decreased morbidity from uterine evacuation. Follow-up with human chorionic gonadotropin (hCG) is essential for early diagnosis of gestational trophoblastic neoplasia (GTN). The duration of hCG monitoring varies depending on histological type and regression rate. Low-risk GTN (FIGO Stages I-III: score <7) is treated with single-agent chemotherapy but may require additional agents; although scores 5-6 are associated with more drug resistance, overall survival approaches 100%. High-risk GTN (FIGO Stages II-III: score ≥7 and Stage IV) is treated with multiagent chemotherapy, with or without adjuvant surgery for excision of resistant foci of disease or radiotherapy for brain metastases, achieving a survival rate of approximately 90%. Gentle induction chemotherapy helps reduce early deaths in patients with extensive tumor burden, but late mortality still occurs from recurrent treatment-resistant tumors.

Evaluation of Epithelioid Trophoblastic Tumor in the Light of Literature.

Epithelioid trophoblastic tumors (ETTs) are extremely rare gestational trophoblastic neoplasia and a subtype of the placental site trophoblastic tumors (PSTTs). To our knowledge, there have been only 110 patients diagnosed with the ETT. ETT is generally seen in the reproductive period, following term pregnancy. Generally, as in PSTT, ß-HCG levels are normal or slightly elevated. The most common complaint is abnormal vaginal bleeding. At the time of diagnosis, findings of metastasis can be seen in 50% of the cases. Transvaginal ultrasonography (TV-USG) and computed tomography (CT) are used for imaging in the literature. Surgical treatment and follow-up are sufficient in the early stages. We present a case of a 37-year-old ETT patient who suffered from irregular vaginal bleeding.

Long-term survival in multiresistant metastatic choriocarcinoma after pembrolizumab treatment: A case report.

•Checkpoint inhibitor therapy affecting PD-L1 as treatment for advanced solid tumors.•Success in trial pembrolizumab therapy in multiresistant metastatic choriocarcinoma.•Long-term remission after pembrolizumab therapy in multiresistant choriocarcinoma.•Only six reported cases, one with comparable follow-up and outcome.

Treatment of metastatic placental site trophoblastic tumor with surgery, chemotherapy, immunotherapy and coil embolization of multiple pulmonary arteriovenous fistulate.

Placental Site Trophoblastic Tumor (PSTT) is a rare malignancy that often presents with extensive disease and can be resistant to traditional treatments. We present the case of a woman with stage IV PSTT who was initially managed with neoadjuvant chemotherapy followed by tumor debulking. Adjuvant therapy was guided by further pathologic analysis that revealed high levels of staining for PD-L1 as well as the presence of tumor infiltrating lymphocytes (TILs). Subsequently, the patient was treated with traditional chemotherapy with the EP/EMA regimen with the addition of pembrolizumab. The patient's treatment course was complicated by the development of pulmonary arteriovenous malformations, autoimmune thyroiditis thought to be secondary to immunotherapy, and significant tinnitus secondary to platinum agents. Currently the patient is in follow up and remains in a complete remission.

Core 2 ß1,6-N-acetylglucosaminyltransferases accelerate the escape of choriocarcinoma from natural killer cell immunity.

Hyperglycosylated human chorionic gonadotropin (H-hCG) is secreted from choriocarcinoma and contains a core2 O-glycan formed by core2 ß1,6-N-acetylglucosaminyl transferase (C2GnT). Choriocarcinoma is considered immunogenic as it is gestational and contains paternal chromosomal components. Here we examined the function of C2GnT in the evasion of choriocarcinoma cells from natural killer (NK) cell-mediating killing. We determined that C2GnT is highly expressed in malignant gestational trophoblastic neoplasms. C2GnT KO downregulates core2 O-glycan expression in choriocarcinoma cells, which are more efficiently killed by NK cells than control cells. C2GnT KO cell containing tumor necrosis factor-related apoptosis inducing ligand have lower viability than control cells. Additionally, poly-N-acetyllactosamine in core2 branched oligosaccharides on MHC class I-related chain A (MICA) and mucin1 (MUC1) is significantly reduced in C2GnT KO cells. Meanwhile, the cumulative survival rate of nude mice inoculated with C2GnT KO tumors was higher than that of the control group. These findings suggest that choriocarcinoma cells may escape NK cell-mediated killing via glycosylation of MICA and MUC1.

Epithelioid trophoblastic tumor presenting as a Caesarean scar defect: A case report.

BACKGROUND: Epithelioid trophoblastic tumor is a rare form of gestational trophoblastic neoplasia. We present the first known case of this rare malignancy presenting as a Caesarean scar defect. CASE: A patient with 3 prior Caesarean sections presented with vaginal bleeding 2 months following management of retained products of conception. Her hCG was negative. She underwent surgical repair of a Caesarean scar defect, and pathology was consistent with epithelioid trophoblastic tumor. CONCLUSION: This case highlights the possibility of malignancy presenting to the general gynecologist as a Caesarean scar defect. The diagnosis of gestational trophoblastic neoplasia should always be considered in the differential diagnosis of a patient with postpartum vaginal bleeding. Limited evidence on fertility conserving treatment of epithelioid trophoblastic tumors does not seem favorable.

Guideline No. 408: Management of Gestational Trophoblastic Diseases.

OBJECTIVE: This guideline reviews the clinical evaluation and management of gestational trophoblastic diseases, including surgical and medical management of benign, premalignant, and malignant entities. The objective of this guideline is to assist health care providers in promptly diagnosing gestational trophoblastic diseases, to standardize treatment and follow-up, and to ensure early specialized care of patients with malignant or metastatic disease. INTENDED USERS: General gynaecologists, obstetricians, family physicians, midwives, emergency department physicians, anaesthesiologists, radiologists, pathologists, registered nurses, nurse practitioners, residents, gynaecologic oncologists, medical oncologists, radiation oncologists, surgeons, general practitioners in oncology, oncology nurses, pharmacists, physician assistants, and other health care providers who treat patients with gestational trophoblastic diseases. This guideline is also intended to provide information for interested parties who provide follow-up care for these patients following treatment. TARGET POPULATION: Women of reproductive age with gestational trophoblastic diseases. OPTIONS: Women diagnosed with a gestational trophoblastic disease should be referred to a gynaecologist for initial evaluation and consideration for primary surgery (uterine evacuation or hysterectomy) and follow-up. Women diagnosed with gestational trophoblastic neoplasia should be referred to a gynaecologic oncologist for staging, risk scoring, and consideration for primary surgery or systemic therapy (single- or multi-agent chemotherapy) with the potential need for additional therapies. All cases of gestational trophoblastic neoplasia should be discussed at a multidisciplinary cancer case conference and registered in a centralized (regional and/or national) database. EVIDENCE: Relevant studies from 2002 onwards were searched in Embase, MEDLINE, the Cochrane Central Register of Controlled Trials, and Cochrane Systematic Reviews using the following terms, either alone or in combination: trophoblastic neoplasms, choriocarcinoma, trophoblastic tumor, placental site, gestational trophoblastic disease, hydatidiform mole, drug therapy, surgical therapy, radiotherapy, cure, complications, recurrence, survival, prognosis, pregnancy outcome, disease outcome, treatment outcome, and remission. The initial search was performed in April 2017 and updated in May 2019. Relevant evidence was selected for inclusion in the following order: meta-analyses, systematic reviews, guidelines, randomized controlled trials, prospective cohort studies, observational studies, non-systematic reviews, case series, and reports. Additional significant articles were identified through cross-referencing the identified reviews. The total number of studies identified was 673, with 79 studies cited in this review. VALIDATION METHODS: The content and recommendations were drafted and agreed upon by the authors. The Executive and Board of Directors of the Society of Gynecologic Oncology of Canada reviewed the content and submitted comments for consideration, and the Board of Directors for the Society of Obstetricians and Gynaecologists of Canada approved the final draft for publication. The quality of evidence was rated using the criteria described in the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology framework. See the online appendix tables for key to grading and interpretation of recommendations. BENEFITS: These guidelines will assist physicians in promptly diagnosing gestational trophoblastic diseases and urgently referring patients diagnosed with gestational trophoblastic neoplasia to gynaecologic oncology for specialized management. Treating gestational trophoblastic neoplasia in specialized centres with the use of centralized databases allows for capturing and comparing data on treatment outcomes of patients with these rare tumours and for optimizing patient care. SUMMARY STATEMENTS (GRADE RATINGS IN PARENTHESES): RECOMMENDATIONS (GRADE RATINGS IN PARENTHESES).