Objective:To investigate the clinical features and outcomes of patients with light-chain (AL) amyloidosis with an ultra-high level of serum free light-chain (FLC) .Methods:Five hundred and ninety-five patients with AL amyloidosis were retrospectively reviewed between January 2009 and January 2020 at Peking Union Medical College Hospital. We analyzed the clinical features and prognosis of patients with ultra-high FLC levels [difference between involved and uninvolved light chains (dFLC) >500 mg/L; n=124] and those without ultra-high FLC levels (dFLC≤500 mg/L; n=471) . Results:Patients with ultra-high FLC presented with more frequent cardiac involvement (82.3% vs 70.1%, P=0.007) , and a higher percentage of patients with 2004 Mayo Ⅲ stage (41.8% vs 33.8%, P=0.029) , but less frequent renal involvement than patients without an ultra-high FLC (59.7% vs 71.8%, P=0.009) . Patients with an ultra-high FLC achieved a lower proportion of hematologic (72.4% vs 82.3%, P=0.048) and cardiac response (37.3% vs 54.7%, P=0.016) and had shorter overall survival (13.0 months vs not reached, P<0.001) and a higher early death rate within 3 months (28.2% vs 11.3%, P<0.001) than those without an ultra-high FLC. Ultra-high FLC independently predicted worse prognosis in patients with AL amyloidosis ( HR=2.279, 95% CI 1.685-3.083, P<0.001) . Conclusions:Patients with an initially ultra-high FLC represented a subgroup with more common cardiac involvement, more advanced cardiac stages, and extremely poor prognosis.

Advances in novel drugs, therapies, and genetic techniques have revolutionized the diagnosis and treatment of cancers, substantially improving cancer patients' prognosis. Although rare tumors account for a non-negligible number, the practice of precision medicine and development of novel therapies are largely hampered by many obstacles. Their low incidence and drastic regional disparities result in the difficulty of informative evidence-based diagnosis and subtyping. Sample exhaustion due to difficulty in diagnosis also leads to a lack of recommended therapeutic strategies in clinical guidelines, insufficient biomarkers for prognosis/efficacy, and inability to identify potential novel therapies in clinical trials. Herein, by reviewing the epidemiological data of Chinese solid tumors and publications defining rare tumors in other areas, we proposed a definition of rare tumor in China, including 515 tumor types with incidences of less than 2.5/100 000 per year. We also summarized the current diagnosis process, treatment recommendations, and global developmental progress of targeted drugs and immunotherapy agents on the status quo. Lastly, we pinpointed the current recommendation chance for patients with rare tumors to be involved in a clinical trial by NCCN. With this informative report, we aimed to raise awareness on the importance of rare tumor investigations and guarantee a bright future for rare tumor patients.
Humans ; Neoplasms/pathology* ; Biomarkers ; Prognosis ; Oceans and Seas ; China/epidemiology*