Impact of Hepatitis B Surface and Core Antibody Levels on Hepatitis B Virus Reactivation.

Hepatitis B virus reactivation (HBV-R) is a serious complication that can occur in patients with resolved HBV infection during cancer chemotherapy. We examined the levels of HBV surface antibody (HBsAb) and HBV core antibody (HBcAb) to assess the incidence of HBV-R in cancer patients including hematopoietic stem cell transplantation (HSCT) and rituximab administration. This retrospective cohort study included 590 patients with resolved HBV infection. The incidence of HBV-R was evaluated 761.5 (range, 90-3898) days after the inititiation of chemotherapy. Of the patients, 13 (2.2%) developed HBV-R after the start of chemotherapy. All 13 patients exhibited lower HBsAb (<100 mIU/mL) levels at baseline. A higher level of HBcAb (≥100 cut off index (C.O.I.)) was a possible risk factor for HBV-R as well as HSCT and rituximab administration. The simultaneous presence of HBsAb <100 mIU/mL and HBcAb ≥100 C.O.I. increased the risk of HBV-R by 18.5%. Patients treated with rituximab were at a higher risk of HBV-R (18.4%) despite having HBcAb <100 C.O.I. Our results suggest that assessment of HBsAb and HBcAb levels prior to the chemotherapy is important for identifying patients at high risk of HBV-R, especially in solid cancers without HSCT and rituximab administration.

Early Detection and Prediction of Anthracycline-Induced Cardiotoxicity　- A Prospective Cohort Study.

BACKGROUND: In the present study, we aimed to investigate whether early cardiac biomarker alterations and echocardiographic parameters, including left atrial (LA) strain, can predict anthracycline-induced cardiotoxicity (AIC) and thus develop a predictive risk score.Methods and Results: The AIC registry is a prospective, observational cohort study designed to gather serial echocardiographic and biomarker data before and after anthracycline chemotherapy. Cardiotoxicity was defined as a reduction in left ventricular ejection fraction (LVEF) ≥10 percentage points from baseline and <55%. In total, 383 patients (93% women; median age, 57 [46-66] years) completed the 2-year follow-up; 42 (11.0%) patients developed cardiotoxicity (median time to onset, 292 [175-440] days). Increases in cardiac troponin T (TnT) and B-type natriuretic peptide (BNP) and relative reductions in the left ventricular global longitudinal strain (LV GLS) and LA reservoir strain [LASr] at 3 months after anthracycline administration were independently associated with subsequent cardiotoxicity. A risk score containing 2 clinical variables (smoking and prior cardiovascular disease), 2 cardiac biomarkers at 3 months (TnT ≥0.019 ng/mL and BNP ≥31.1 pg/mL), 2 echocardiographic variables at 3 months (relative declines in LV GLS [≥6.5%], and LASr [≥7.5%]) was generated. CONCLUSIONS: Early decline in LASr was independently associated with subsequent cardiotoxicity. The AIC risk score may provide useful prognostication in patients receiving anthracyclines.

Efficacy of Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitors in Metastatic Non-Small Cell Lung Cancer Patients with Poor Performance Status and Epidermal Growth Factor Receptor Mutations: Findings from the Japanese Lung Cancer Registry Database.

BACKGROUND: In advanced non-small cell lung cancer (NSCLC) patients harboring epidermal growth factor receptor (EGFR) mutations, those with impaired performance status (PS) treated with EGFR-tyrosine kinase inhibitors (TKIs) have demonstrated comparable activities to good-PS patients. Due to the limited sample size and inclusion of older adult patients with good PS, these findings may not accurately depict the efficacy of EGFR-TKI in poor-PS patients. We investigated the benefit of EGFR-TKIs in this population and identified relevant prognostic factors. PATIENTS AND METHODS: This nationwide prospective registry study included 9872 patients with local or advanced NSCLC. Outcomes were compared between poor- and good-PS patients treated with EGFR-mutated lung cancer therapies. RESULTS: Of 9872 NSCLC patients, 1965 (19.9%) had EGFR mutations, with 1846 (93.9%) presenting common EGFR mutations. Poor PS (PS score ≥ 3) was noted in 171 patients (8.7%) and identified as an independent prognostic factor; those with poor PS had a significantly lower 1-year survival rate. The median overall survival (OS) for EGFR-TKI-treated good-PS patients was 31.5 (95% confidence interval, 29.6-33.4) months. Among poor-PS patients with EGFR mutations, 135 (78.9%) of whom were treated with EGFR-TKI had an OS of 15.5 (12.7-18.3) months, while those receiving only supportive care had an OS of 2.5 (1.4-3.6) months (P < .001). Hypoalbuminemia (< 3.5 g/dL), liver metastasis, and uncommon EGFR mutations were associated with poor prognosis. CONCLUSION: Poor PS at diagnosis was rare and associated with limited EGFR-TKI efficacy and a dismal prognosis. Liver metastasis and hypoalbuminemia may reduce EGFR-TKI efficacy in these patients.

Japanese Society of Medical Oncology/Japan Society of Clinical Oncology/Japanese Society of Pediatric Hematology/Oncology-led clinical recommendations on the diagnosis and use of immunotherapy in patients with DNA mismatch repair deficient (dMMR) tumors, third edition.

BACKGROUND: Clinical trials have reported the efficacy of immune checkpoint inhibitors in the treatment of mismatch repair-deficient (dMMR) advanced solid tumors. The accumulated evidence of tumor agnostic agent has been made since PD-1 inhibitor was approved and used in clinical practice. Therefore, we have revised the guideline "Japan Society of Clinical Oncology provisional clinical opinion for the diagnosis and use of immunotherapy in patients with deficient DNA mismatch repair tumors, cooperated by Japanese Society of Medical Oncology, First Edition". METHODS: Clinical questions regarding medical care were formulated for patients with dMMR advanced solid tumors. Relevant publications were searched by PubMed and Cochrane Database. Critical publications and conference reports were added manually. Systematic reviews were performed for each clinical question for the purpose of developing clinical recommendations. The committee members identified by Japan Society of Clinical Oncology (JSCO), Japanese Society of Medical Oncology (JSMO), and Japanese society of pediatric hematology/oncology (JSPHO) voted to determine the level of each recommendation considering the strength of evidence, expected risks and benefits to patients, and other related factors. Thereafter, a peer review by experts nominated from JSCO, JSMO, and JSPHO and the public comments among all societies' members were done. RESULTS: The current guideline describes two clinical questions and eight recommendations for whom, when, and how MMR status should be tested. CONCLUSION: In this guideline, the committee proposed eight recommendations for performing MMR testing properly to select patients who are likely to benefit from immunotherapy.

Japanese Society of Medical Oncology/Japan Society of Clinical Oncology/Japanese Society of Pediatric Hematology/Oncology-led clinical recommendations on the diagnosis and use of immunotherapy in patients with high tumor mutational burden tumors.

The development of novel antitumor agents and accompanying biomarkers has improved survival across several tumor types. Previously, we developed recommendations for tumor-agnostic treatments in patients with solid tumors with DNA mismatch repair deficient or neurotrophic receptor tyrosine kinase fusions. Recently, immune checkpoint inhibitors have shown efficacy in patient with tumor mutation burden-high (TMB-H) solid tumors and have been established as a third tumor-agnostic agent, making it necessary to develop the guideline prioritized for these patients. Clinical questions regarding medical care were formulated for patients with TMB-H advanced solid tumors. Relevant publications were searched by PubMed and Cochrane Database. Critical publications and conference reports were added manually. Systematic reviews were performed for each clinical question for the purpose of developing clinical recommendations. The committee members identified by Japan Society of Clinical Oncology (JSCO), Japanese Society of Medical Oncology (JSMO), and Japanese society of pediatric hematology/oncology (JSPHO) voted to determine the level of each recommendation considering the strength of evidence, expected risks and benefits to patients, and other related factors. Thereafter, a peer review by experts nominated from JSCO, JSMO, and JSPHO, and the public comments among all societies' members was done. The current guideline describes three clinical questions and seven recommendations for whom, when, and how TMB should be tested, and what is recommended for patients with TMB-H advanced solid tumors. In this guideline, the committee proposed seven recommendations for performing TMB testing properly to select patients who are likely to benefit from immunotherapy.

Japanese Society of Medical Oncology/Japan Society of Clinical Oncology/Japanese Society of Pediatric Hematology/Oncology-led clinical recommendations on the diagnosis and use of tropomyosin receptor kinase inhibitors in adult and pediatric patients with neurotrophic receptor tyrosine kinase fusion-positive advanced solid tumors.

BACKGROUND: Clinical trials have reported the efficacy of tropomyosin receptor kinase (TRK) inhibitors against neurotrophic receptor tyrosine kinase (NTRK) fusion gene-positive advanced solid tumors. The accumulated evidence of tumor-agnostic agent has made since TRK inhibitors were approved and used in clinical practice. Therefore, we have revised the 'Japan Society of Clinical Oncology (JSCO)/Japanese Society of Medical Oncology (JSMO)-led clinical recommendations on the diagnosis and use of tropomyosin receptor kinase inhibitors in adult and pediatric patients with neurotrophic receptor tyrosine kinase fusion-positive advanced solid tumors, cooperated by the Japanese Society of Pediatric Hematology/Oncology (JSPHO)'. METHODS: Clinical questions regarding medical care were formulated for patients with NTRK fusion-positive advanced solid tumors. Relevant publications were searched by PubMed and Cochrane Database. Critical publications and conference reports were added manually. Systematic reviews were performed for each clinical question for the purpose of developing clinical recommendations. The committee members identified by JSCO, JSMO, and JSPHO voted to determine the level of each recommendation considering the strength of evidence, expected risks and benefits to patients, and other related factors. Thereafter, a peer review by experts nominated from JSCO, JSMO, and JSPHO, and the public comments among all societies' members was done. RESULTS: The current guideline describes 3 clinical questions and 14 recommendations for whom, when, and how NTRK fusion should be tested, and what is recommended for patients with NTRK fusion-positive advanced solid tumors. CONCLUSION: The committee proposed 14 recommendations for performing NTRK testing properly to select patients who are likely to benefit from TRK inhibitors.

Epidemiology, risk factors and impact of cachexia on patient outcome: Results from the Japanese Lung Cancer Registry Study.

BACKGROUND: Cancer cachexia is a syndrome that does not fully recover with nutritional support and causes appetite loss and body weight loss. It worsens a patient's quality of life and prognosis. In this study, the epidemiology of cachexia in lung cancer, its risk factors and its impact on chemotherapy response rate and prognosis were examined using the national database of the Japan Lung Cancer Society. Understanding these things related to cancer cachexia is important as a starting point in overcoming cancer cachexia in patients with lung cancer. METHODS: In 2012, 12 320 patients from 314 institutions in Japan were registered in a nationwide registry database (Japanese Lung Cancer Registry Study). Of these, data on body weight loss within 6 months were available for 8489 patients. We defined the patients with body weight loss ≥ 5% within 6 months, which is one of the three criteria listed in the 2011 international consensus definition of cancer cachexia, as cachectic in this study. RESULTS: Approximately 20.4% of the 8489 patients had cancer cachexia. Sex, age, smoking history, emphysema, performance status, superior vena cava syndrome, clinical stage, site of metastasis, histology, epidermal growth factor receptor (EGFR) mutation status, primary treatment method and serum albumin levels were significantly different between patients with and without cachexia. Logistic analyses showed that smoking history, emphysema, clinical stage, site of metastasis, histology, EGFR mutation, serum calcium and albumin levels were significantly associated with cancer cachexia. The response to initial therapy, including chemotherapy, chemoradiotherapy or radiotherapy, was significantly poorer in the patients with cachexia than in those without cachexia (response rate: 49.7% vs. 41.5%, P < 0.001). Overall survival was significantly shorter in the patients with cachexia than in those without cachexia in both univariate and multivariable analyses (1-year survival rate: 60.7% vs. 37.6%, Cox proportional hazards model, hazard ratio: 1.369, 95% confidence interval: 1.274-1.470, P < 0.001). CONCLUSIONS: Cancer cachexia was seen in approximately one fifth of the lung cancer patients and was related to some baseline patient characteristics. It was also associated with a poor response to initial treatment, resulting in poor prognosis. The results of our study may be useful for early identification and intervention in patients with cachexia, which may improve their response to treatment and their prognosis.

[Pharmacologic Therapy for Bone Metastases-Current Strategies and Future Directions].

Bisphosphonates were introduced in the late 1990s to reduce the frequency of skeletal-related events(SREs)in patients with metastatic bone disease. In the 2010s, anti-RANKL antibodies were launched as another type of bone modifying agents(BMA). Both induce osteoclast apoptosis and have been used in Japan for solid tumors with bone metastases and multiple myeloma. In addition to osteoclasts, bone microenvironment includes a wide variety of cells such as osteoblasts, vascular endothelial cells, and immune cells, which spatiotemporally interact with cancer cells, resulting in the colonization of dissociated tumor cells(DTCs). Understanding the pathways and microenvironmental factors through which cancer evolves to promote bone colony formation will lead to better planning of the therapeutic strategies in individual cases and to further elucidation of molecular drivers.

Clonal heamatopoiesis and associated cardiovascular diseases.

Cancer and cardiovascular disease share several risk factors. Clonal heamatopoiesis, a novel risk factor associated with both diseases, has received increasing attention in the fields of cardiology, heamatology and oncology. Clonal heamatopoiesis of indeterminate potential refers to the presence of at least one driver mutation in the heamatopoietic cells of peripheral blood without heamatological malignancy. Clonal heamatopoiesis of indeterminate potential is a common age-related condition that affects up to 60% of individuals aged > 80 years. Importantly, clonal heamatopoiesis of indeterminate potential carriers have a 2- to 4-fold higher risk of developing cardiovascular disease than non-carriers. Therefore, we performed an up-to-date review of clonal heamatopoiesis and its association with various forms of cardiovascular disease, including atherosclerotic disease, heart failure, aortic stenosis and pulmonary hypertension. In addition, we reviewed experimental studies that examined the causality and directionality between clonal heamatopoiesis and cardiovascular disease. Lastly, we discussed future research directions that will aid in the design of personalized therapies and preventive strategies for individuals with clonal heamatopoiesis. This review showed that clonal heamatopoiesis of indeterminate potential is a common condition, especially in older patients, and is associated with an increased risk of cardiovascular disease and worse prognosis. However, further research is needed to determine whether anti-inflammatory therapies or therapies that can reduce or eliminate clone size are effective in preventing cardiovascular disease in patients with clonal heamatopoiesis of indeterminate potential.

Effects of lymphopenia on survival in proton therapy with chemotherapy for non-small cell lung cancer.

Lymphocytes play an important role in the cancer immune system. In the present study, we aimed to evaluate the associations of lymphopenia during proton beam therapy (PBT) and concurrent chemotherapy with clinical outcomes and to determine whether lung or bone is more influential on lymphopenia during PBT. Data from 41 patients with stage III non-small cell lung cancer (NSCLC) who received PBT of 74 GyE with concurrent chemotherapy between 2007 and 2017 were reviewed retrospectively. The correlation between dosimetry parameters obtained from dose-volume histograms of the bone and lung and lymphopenia during PBT were analyzed. Minimum absolute lymphocyte count (ALCmin) and maximum neutrophil/lymphocyte ratio (NLRmax) were used as indicators of lymphopenia. Bone V5-20 and lung V5-50 were significantly correlated with the ALCmin and NLRmax during PBT. Multivariable analysis showed that the NLRmax, but not the ALCmin, was associated with overall survival (OS), progression-free survival (PFS) and distant metastasis-free survival (DMFS). The 3-year rates of OS, PFS and DMFS of patients with a low (≤ 6.3) versus high (> 6.3) NLRmax were 73.9% vs 44.4% (P = 0.042), 26.1% vs 5.6% (P = 0.022) and 39.1% vs 5.6% (P < 0.001), respectively. Lung V20 was significantly associated with DMFS on multivariable analyses (hazard ratio: 1.094, P = 0.008), whereas bone V5 had no impact on survival outcomes. We concluded that the NLRmax was a better prognostic indicator than the ALCmin, and the lung dose had more influence than the bone dose on the main survival outcomes in stage III NSCLC patients treated with PBT combined with concurrent chemotherapy.

[Maturation and Development of the"All Japan E-Learning Cloud of the Training Program for Oncology Professionals].

This paper reports the 5-year operational status of the third phase of the"All Japan E-Learning Cloud of the Training Program for Oncology Professionals"by tabulating the viewing trends of available lecture contents. In this phase, the goal was to train cancer genome medical professionals in this new, advanced medical technology field as well as train personnel to treat rarely encountered pediatric, adolescent/young adult, and other life stage cancers. Additionally, new lecture items have been added to the e-learning cloud in collaboration with 7 oncology specialist centers, contributing to the development of human capital in cancer care(including graduate student education)and faculty development for local medical professionals.

Prognostic Implication of PD-L1 Expression on Osimertinib Treatment for EGFR-mutated Non-small Cell Lung Cancer.

BACKGROUND/AIM: Real-world data on the clinical outcomes of first-line osimertinib treatment for non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations is lacking. This study aimed to reveal the treatment outcomes and prognostic factors of osimertinib as first-line therapy in clinical practice settings. PATIENTS AND METHODS: We retrospectively evaluated clinical outcomes of patients with EGFR-mutated NSCLC treated with osimertinib as first-line therapy across 12 institutions in Japan between August 2018 and March 2020. RESULTS: Among 158 enrolled patients, the objective response rate (ORR) was 68%, and the estimated median progression-free survival (PFS) was 17.1 months [95% confidence interval (CI)=14.5-19.7]. Subgroup analysis showed that PFS in the group with high programmed death-ligand 1 (PD-L1) expression was significantly shorter than that in groups with low or no PD-L1 expression (10.1 vs. 16.1 vs. 19.0 months; p=0.03). Univariate and multivariate analyses demonstrated that high PD-L1 expression was the only independent adverse prognostic factor of osimertinib outcome related to PFS (hazard ratio=2.71; 95%CI=1.26-5.84; p=0.01). In terms of anti-tumor response, there was no statistically significant correlation between PD-L1 expression and the ORR (67% vs. 76% vs. 65%; p=0.51). No significant correlation was also found between PD-L1 and the incidence of de novo resistance to osimertinib (p=0.39). CONCLUSION: Although PD-L1 expression was not associated with either the ORR or frequency of de novo resistance, high PD-L1 expression could be an independent adverse prognostic factor related to PFS in osimertinib treatment.

Efficacy of platinum agents for stage III non-small-cell lung cancer following platinum-based chemoradiotherapy: a retrospective study.

BACKGROUND: Platinum-based chemoradiotherapy is the standard treatment for unresectable stage III non-small-cell lung cancer (NSCLC). However, few studies have evaluated the efficacy of subsequent chemotherapy for relapsed NSCLC following platinum-based chemoradiotherapy. This study aimed to evaluate the efficacy of platinum-doublet chemotherapy as a second-line treatment for patients with unresectable stage III NSCLC. METHODS: We retrospectively evaluated patients with unresectable stage III NSCLC treated with cytotoxic chemotherapy following platinum-based chemoradiotherapy who were registered in a nationwide registry NSCLC database. Patients were divided into the platinum-doublet chemotherapy (platinum) group and single-agent chemotherapy (non-platinum) group based on the type of second-line chemotherapy. RESULTS: The platinum group (n = 119) showed significantly better overall survival (OS) than the non-platinum group (n = 201) (median OS: 21.5 vs. 10.5 months, hazard ratio [HR]: 0.54, 95% confidence interval [CI]: 0.40-0.73, p < 0.001). OS from the beginning of chemoradiotherapy was also significantly better in the platinum group than in the non-platinum group (median OS: 34.9 vs. 21.8 months, HR: 0.58, 95% CI: 0.43-0.79, p = 0.001). In the multivariate analysis, platinum-doublet chemotherapy as second-line therapy, female sex, clinical stage IIIA, and duration of ≥ 8.6 months from the beginning of first-line therapy to the beginning of second-line therapy were associated with significantly better OS. CONCLUSION: Platinum-doublet chemotherapy as a second-line therapy may prolong survival in unresectable stage III NSCLC patients following platinum-based chemoradiotherapy. Thus, re-administration of platinum agents may be a promising treatment for unresectable stage III NSCLC treated with platinum-based chemoradiotherapy.

Atherosclerotic cardiovascular events associated with immune checkpoint inhibitors in cancer patients.

Immune checkpoint inhibitors have demonstrated significant clinical benefits in many cancers, and the use of these drugs is rapidly expanding. Unfortunately, these agents can induce a wide range of immune-related adverse events through the activation of immune responses in non-target organs, including the cardiovascular system. Among cardiovascular immune-related adverse events, myocarditis is the most established and biologically plausible cardiac complication of immune checkpoint inhibitors therapy with immune-related pathophysiology. In contrast, atherosclerotic cardiovascular diseases, such as myocardial infarction and ischemic stroke, were not previously recognized as a part of the immune-related adverse event spectrum. However, there is now increasing preclinical and clinical evidence that suggests a possible correlation between immune checkpoint inhibitors therapy and atherosclerotic cardiovascular events, and cardiovascular disease is increasingly recognized as a toxicity of ICIs. Results from animal studies suggest that the blockade of the cytotoxic T-lymphocyte antigen 4 or programmed cell death protein 1 pathway plays a relevant role in promoting the progression of atherosclerotic lesions. Several clinical studies have reported an increased incidence of atherosclerotic vascular events after immune checkpoint inhibitor administration. Our findings suggest that clinicians should (i) recognize that immune checkpoint inhibitors can exacerbate atherosclerosis, (ii) consider the management of cardiovascular risk factors and (iii) perform periodic screening in patients receiving immune checkpoint inhibitors.

Echocardiography image quality of global longitudinal strain in cardio-oncology: a prospective real-world investigation.

BACKGROUND: Left-ventricular (LV) global longitudinal strain (GLS) has been reported to be a robust and sensitive marker of chemotherapy-induced cardiac damage. Image quality is paramount for accurate GLS measurements. In real-world cardio-oncology settings, the incidence of suboptimal echocardiography quality and its significance in clinical decision-making have not been well investigated. This prospective study examined the incidence and impact of suboptimal echocardiographic image quality on detecting subtle myocardial damage by chemotherapy. METHODS: Seventy-seven consecutive patients with breast cancer (age, 52 ± 12 years, 76 women, 33 with left-sided breast cancer) were included in this study. Echocardiography was performed at 3-month intervals 1 year before and after chemotherapy initiation. We classified the image quality of each echocardiographic acquisition into three groups: optimal, suboptimal, or inadequate for speckle tracking. RESULTS: Among the 376 examinations obtained during the cardiac monitoring, the image quality in 194 (52%) was optimal, suboptimal in 159 (42%), and inadequate in 23 (6%). The interobserver reproducibility was 0.91 in the optimal and 0.21 in the suboptimal group. In contrast, the optimal group showed progressive impairment in both GLS (p = 0.001) and LV ejection fraction (LVEF) (p < 0.001) during follow-up, and the suboptimal group showed a progressive decrease in LVEF (p = 0.006), but not in GLS (p = 0.13). Left-sided mammotomy and/or reconstruction surgery and high body mass index were significant determinants of suboptimal image quality. CONCLUSIONS: Even in cases of minor image quality impairment, the physician should assess GLS carefully to avoid errors in crucial clinical decision-making.

Characteristics of Cancers in Adolescents and Young Adults Compared with Those in Adults in Their 60s: A Single-Center Experience.

INTRODUCTION: Cancer is one of the main causes of death among adolescents and young adults (AYAs) aged 15-39 years. The improvement in overall 5-year survival in AYA cancer patients was far below than that of adult cancer patients. The purpose of this study was to clarify the features of cancer in AYAs by comparing them with those of controls. METHODS: Patients in the cancer registry of the University of Tsukuba Hospital between 2007 and 2017 (median age, 65 years) were included in this study. We used patients between the ages of 64 and 66 years as controls. We then obtained the age at diagnosis, sex, primary site, and pathological type. RESULTS: Among 27,281 cancer patients in the registry between 2007 and 2017, 1,947 (7.1%) patients were categorized into the AYA group, and 2,354 into the control group. Among men in the AYA group, central nervous system (CNS) tumors accounted for 22.7% of all cancers, followed by germ cell tumors, 22.5%, and hematopoietic malignancies, 12.5%. Among women in the AYA group, cervical cancer accounted for 35.9% of all cancers, followed by breast cancer, 14.6%, and CNS tumors, 11.6%. The proportion of specific cancer types relative to all cancers in the CNS, thyroid, adrenal glands, germ cells, cervix uteri, hematopoietic tissues, and sarcomas was higher in the AYA group than that in the control group. CONCLUSION: The present results for AYAs were in sharp contrast to those for adult cancers and may be related to different modes of pathogenesis in AYAs. The identification of high-risk groups of these tumors in the AYA generation is crucial for prevention and early detection and will be a major topic for future research. While most of adult cancers are treated independently by each medical department, AYA cancers need to be treated in collaboration with experts from several departments. It is desirable to address the issues involved in applying treatments established for adult cancers to AYA cancers on a cancer-by-cancer basis.

Squamous Cell Carcinoma of Unknown Primary: Multiple Skeletal Metastases Without Detectable Visceral Lesions.

The appropriate diagnosis of carcinoma of unknown primary can be challenging for physicians, especially when they cannot apply a logical and ordered diagnostic process due to the unorthodox clinical characteristics. Here, we report the case of a 75-year-old woman presenting with multiple skeletal metastases with neither detectable visceral lesions nor site-specific distribution. Histological examination of a skeletal biopsy specimen unexpectedly revealed squamous cell carcinoma (SCC). Further specialized investigations led to the diagnosis of SCC of unknown primary. This case highlights the difficulty of the clinical differential diagnostic process in the quest for the occult primary tumor site.