Rare cancers in Japan: definition, clinical features and future perspectives

Histological diagnostic discrepancy and its clinical impact in bone and soft tissue tumors referred to a sarcoma center

Histological diagnosis of sarcomas (malignant bone and soft tissue tumors) is challenging due to their rarity, morphological diversity, and constantly evolving diagnostic criteria. In this study, we aimed to assess the concordance in histological diagnosis of bone and soft tissue tumors between referring hospitals and a tertiary sarcoma center and analyzed the clinical impact of the diagnostic alteration. We analyzed 628 consecutively accessioned specimens from 624 patients who visited a specialized sarcoma center for treatment. The diagnoses at referring hospitals and those at the sarcoma center were compared and classified into four categories: agreed, disagreed, specified, and de-specified. Of the 628 specimens, the diagnoses agreed in 403 (64.2%) specimens, whereas some changes were made in 225 (35.8%) specimens: disagreed in 153 (24.3%), specified in 52 (8.3%), and de-specified in 20 (3.2%) cases. The benign/intermediate/malignant judgment changed for 92 cases (14.6%). The diagnostic change resulted in patient management modification in 91 cases (14.5%), including surgical and medical treatment changes. The main inferred reason for the diagnostic discrepancies was a different interpretation of morphological findings of the tumor, which accounted for 48.9% of the cases. This was followed by the unavailability of specialized immunohistochemical antibodies and the unavailability of genetic analysis. In summary, our study clarified the actual clinical impact of diagnostic discrepancy in bone and soft tissue tumors. This may underscore the value of pathology consultation, facilitating access to specialized diagnostic tools, and continued education. These measures are expected to improve diagnostic precision and ultimately benefit patients.

Challenges and opportunities in rare cancer research in China

Cancer is one of the major public health challenges in China. Rare cancers collectively account for a considerable proportion of all malignancies. The lack of awareness of rare cancers among healthcare professionals and the general public, the typically complex and delayed diagnosis, and limited access to clinical trials are key challenges. Recent years have witnessed an increase in funding for research related to rare cancers in China. In this review, we provide a comprehensive overview of rare cancers and summarize the status of research on rare cancers in China and overseas, including the trends of funding and publications. We also highlight the challenges and perspectives regarding rare cancers in China.

Clinical outcomes of head and neck mucosal melanoma treated with surgery: a single-center study in Japan

BACKGROUND

Head and neck mucosal melanomas are rare malignancies. Although the prognosis is poor owing to the high incidence of distant metastases, locoregional control remains important. It is difficult to obtain results in a large cohort because of its rarity. This study aimed to elucidate the survival outcomes of patients with head and neck mucosal melanoma treated with surgery in Japan.

METHODS

Patients with head and neck mucosal melanoma who were surgically treated between 2007 and 2021 at the National Cancer Center Hospital were retrospectively analyzed.

RESULTS

A total of 47 patients were included in this study. The 5-year overall survival, disease-specific survival, locoregional control and relapse-free survival rates were 42%, 50%, 79% and 13%, respectively. The disease-specific survival of the oral mucosal melanoma group was significantly better than that of the sinonasal mucosal melanoma group (5-year disease-specific survival rate: 70% versus 37%, respectively; P = 0.04). Multivariate analyses revealed that sinonasal mucosal melanoma were independently significant adverse prognostic factor, for overall survival and disease-specific survival. Patients with oral mucosal melanoma patients had a higher incidence of lymph node metastasis than those with sinonasal mucosal melanoma patients (P < 0.0001).

CONCLUSION

This study demonstrated the survival outcomes of the largest cohort of patients with head and neck mucosal melanomas treated surgically at a single institution within the past 20 years in Japan. We found that survival outcomes and incidence of nodal metastases varied by site.

A Rare Pancreatic Tumor with Adenomatoid Tumor-like Findings

A 74-year-old woman was referred to our hospital for the evaluation of slightly elevated tumor marker levels. Computed tomography revealed a well-demarcated tumor, approximately 15 mm in diameter, in the pancreatic tail. Endoscopic ultrasound-guided fine-needle aspiration findings suggested poorly differentiated cancer. The tumor was surgically resected, but postoperative pathologic confirmation was not possible. After one year without treatment and no recurrence, an evaluation by a specialized facility was requested for a definitive diagnosis. Adenomatoid tumor was deemed most likely based on the histopathology and immunostaining findings; however, a definitive diagnosis was difficult because of atypical findings. The patient was recurrence-free for 36 months at the last follow-up.

Assessment of Medical Students' Knowledge of Imaging Methods for Bone Sarcomas

Cancer is a leading cause of death in Brazil and worldwide. However, Brazilian medical education fails to include oncology as an essential topic. This creates a gap between the health status of the population and medical education. Bone sarcomas fall into both the group of malignant neoplasms and rare diseases and are thus doubly influenced by misinformation. To assess medical students' knowledge of imaging diagnostic methods for bone sarcomas. A cross-sectional, quantitative study was undertaken by obtaining the responses of medical students to a questionnaire containing radiographic images and questions about the radiological aspects of bone sarcomas. The categorical variables were compared using the chi-square test. The level of significance was 5% for all the tests. SPSS software version 25.0 was used for the analysis. A total of 325 responses were collected, with 72% of the participants having no interest in oncology and 55.6-63.9% not knowing how to diagnose a periosteal reaction on bone radiography. Only 11.1-17.1% of the students correctly interpreted the radiographic image of osteosarcoma. Medical students fail to correctly interpret images of bone sarcomas. It is important to promote oncology undergraduate education in general and to include the approach to bone sarcomas in this context.

Epidemiology of skin cancer based on Japan's National Cancer Registry 2016-2017

Skin cancer is most frequently diagnosed in the White population. However, its subtypes and epidemiology in Japan are understudied. We aimed to elucidate skin cancer incidence in Japan based on the National Cancer Registry, a new nationwide integrated population-based registry. Data from patients diagnosed with skin cancer in 2016 and 2017 were extracted and classified by cancer subtypes. Data were analyzed using the World Health Organization and General Rules tumor classifications. Tumor incidence was calculated as the number of new cases divided by the corresponding total person-years. Overall, 67,867 patients with skin cancer were included. The percentage of each subtype was as follows: basal cell carcinoma, 37.2%; squamous cell carcinoma, 43.9% (18.3% of which, in situ); malignant melanoma, 7.2% (22.1% of which, in situ); extramammary Paget's disease, 3.1% (24.9% of which, in situ); adnexal carcinoma, 2.9%; dermatofibrosarcoma protuberans, 0.9%; Merkel cell carcinoma, 0.6%; angiosarcoma, 0.5%; and hematologic malignancies, 3.8%. The overall age-adjusted incidence of skin cancer was 27.89 for the Japanese population model and 9.28 for the World Health Organization (WHO) model. The incidences of basal cell carcinoma and squamous cell carcinoma were the highest (3.63 and 3.40 per 100,000 persons, respectively, in the WHO model) among skin cancers, whereas the incidences of angiosarcoma and Merkel cell carcinoma were the lowest (0.026 and 0.038 per 100,000 persons, respectively, in the WHO model). This is the first report to provide comprehensive information on the epidemiological status of skin cancers in Japan using population-based NCR data.

Involvement of orthopaedic surgeons for cancer patients in orthopaedic training facilities certified by the Japanese Orthopaedic Association - A nationwide survey

BACKGROUND

In order to improve cancer care in Japan further, it is now required for orthopaedic surgeons to get actively involved in managing locomotive organs such as bones, muscles and nerves in cancer patients. In 2018, the Japanese Orthopaedic Association (JOA) conducted a questionnaire survey to investigate the current status of cancer treatment at the orthopaedic training facilities certified by the JOA. We analyzed the results of that questionnaire survey, focusing on the data from the core hospitals for cancer care (designated cancer hospitals), to clarify the involvement of orthopaedic surgeons in cancer treatment.

MATERIALS AND METHODS

A nationwide survey was conducted in the orthopaedic training facilities certified by the JOA using an online questionnaire from March 15th to 31st, 2018. To clarify the involvement of orthopaedic surgeons in cancer treatment, we analyzed the results of that questionnaire survey, focusing on the data from the designated cancer hospitals in Japan.

RESULTS

From the questionnaire survey, it became clear that 24% of the orthopaedic training facilities certified by the JOA are designated cancer hospitals. There were significant differences concerning cancer treatment and the prospect of orthopaedic surgeons' involvement in the treatment for bone metastases between institutions classified according to number of both certified orthopaedic surgeons by the JOA and specialists for bone and soft tissue tumors. In addition, in 45% of the designated cancer hospitals, orthopaedic surgeons treated bone metastases that occur in cancer patients, but in the rest of the institutions, orthopaedic surgeons did not yet adequately respond.

CONCLUSION

In order to further improve the locomotive function and quality of life (QOL) in cancer patients, it was seemed to be necessary that all medical professionals engaged in cancer treatment, including orthopaedic surgeons, recognize the importance of locomotive management for cancer patients. In addition, the results of this study suggested that the presence of more than six certified orthopaedic surgeons by the JOA, including one or more specialists for bone and soft tissue tumors, may be able to create an environment conducive to the involvement of orthopaedic surgeons in cancer treatment at the facility.

Druggable gene alterations in Japanese patients with rare malignancy

Without a current standard of care, patients with rare malignancy are subjected to precision oncology with next-generation sequencing to identify a course of treatment. We sought to establish the clinical relevance of comprehensive genomic profiling (CGP) among patients with rare malignancy. Rare malignancy was defined using the Rare Cancers in Europe definition (<6 cases per 100,000 individuals). We analyzed gene mutations, fusions, tumor mutational burden (TMB), and microsatellite instability (MSI) status. Level A gene alterations, categorized using Clinical Interpretations of Variants in Cancer and MD Anderson Knowledge Base for Precision Oncology, were considered druggable. Rare malignancy accounted for 149 (45%) cases, with female genital cancers (32%) most common. Among the rare malignancy cases, we identified a lower frequency of mutation in TP53 (41% vs. 60%, P<0.001), KRAS (13% vs. 43%, P<0.001) and APC (3% vs. 25%, P<0.001), and a higher frequency of ARID1A mutation (14% vs. 6%, P=0.03), as compared with common malignancies. TMB-high and MSI-high cases were found in 8% and 2% of cases, respectively. Druggable alterations were detected in 37 patients with rare malignancy; this percentage tended to be higher than that for patients with common malignancies (25% vs. 17%, P=0.08). Common druggable alterations were BRAF V600E, ERBB2 amplification, PIK3CA E542K, and BRCA1/2 variant. Five of the 37 patients with druggable alterations received genome-driven treatment. There was no significant difference in overall survival between the rare and common malignancy groups. Our results provide clues for future clinical development and treatment success among Japanese patients with rare cancers.

Guidelines for clinical evaluation of anti-cancer drugs

Clinical studies intended for regulatory approval must demonstrate the clinical benefits of the drug in a target population. Clinical development of a drug proceeds by stepwise clinical studies; after safety and pharmacokinetics are evaluated and the recommended dosage and administration are determined, efficacy and safety are evaluated in an exploratory manner, and finally clinical benefits are compared with conventional standard therapies. Guidelines for the clinical evaluation of anti‐cancer drugs in Japan were established in 1991 and amended in 2006 after molecular‐targeted drugs were introduced. Recent progress in the development of drugs acting on the immune system and cancer genomic medicine targeting rare but important molecular subtypes have altered the strategy for development of anti‐cancer drugs. It is often difficult to conduct a confirmatory randomized controlled study using overall survival as the primary endpoint in rare molecular subtypes, and the primary evaluation of the efficacy of some drugs and subsequent approval is based on the tumor response. As conducting clinical studies for rare subtypes solely within Japan is difficult, drug development needs to be conducted within a global study. However, this requires robust monitoring to detect possible ethnic differences in pharmacokinetics and drug efficacy. Development using the conditional approval system for drugs enforced in 2020 may be considered, when clinical utility is evaluated based on surrogate endpoints. Because of these changes, we have revised the guidelines for the clinical evaluation of anti‐cancer drugs in Japan. To promote global development of anti‐cancer drugs involving Japan, the guidelines have been translated into English.

Recent progress in development of drugs acting on the immune system and cancer genomic medicine targeting rare but important molecular subtypes have altered the strategy for development of anti‐cancer drugs. As conducting clinical studies for rare subtypes solely within Japan is difficult, drug development needs to be conducted within a global study with monitoring possible ethnic differences. Because of these changes, we have revised the guidelines for the clinical evaluation of anti‐cancer drugs in Japan.