Table 2

Cancer and cancer therapy associated with RS3PE

	Association	Timeline for the occurrence of RS3PE	Treatment	Prognosis	Comment
1.	Lung cancer	Before	Pembrolizumab	Good	In this case, RS3PE developed as paraneoplastic diseases.
2	Pembrolizumab therapy Treatment: low-dose prednisolone	After initiation of treatment	Pembrolizumab	Good	Baseline use of corticosteroid equivalent to 10 mg of prednisone shown to be associated with a decreased overall response rate, progression-free survival and overall survival after PD-1/PD-L1 treatment. Use of steroids may be suitable for paraneoplastic RS3PE syndrome if needed; however, the risk-benefit balance of steroids should be considered carefully during ICI therapy.
3	Nivolumab therapy: a patient-specific report	After initiation of therapy	Continued nivolumab and managed RS3PE with corticosteroids	Good	Side effect of immune checkpoint inhibitor use is the higher incidence of immune-mediated side effects that can prompt discontinuation of therapy.
4	Nivolumab therapy: a patient-specific report	After initiation of therapy	Nivolumab discontinued Corticosteroids initiated	Good	In some cases, the discontinuation of immune checkpoint inhibitors may be needed for disease regression.
5	Adenocarcinoma of the prostate	After 3 years of prostate adenocarcinoma diagnosis	Prednisolone 15 mg/day was started resulting in rapid resolution of the symptoms	Good	Presence of RS3PE in relation with PMR and prostate cancer.
6	Phyllodes tumor of breast	Unknown	Unknown Corticosteroids may help	Unknown	A quarter of the cases recur after definitive treatment. This is an unusual association of RS3PE with recurrent phyllodes tumor of the breast.
7	Prostate adenocarcinoma	Before the diagnosis is established	Diclofenac, oral prednisolone, anti-androgen therapy	Good	In a clinical setting of RS3PE syndrome, clinicians should consider malignancies in the absence of other associated rheumatic diseases, in the presence of systemic signs and symptoms and if the response to corticosteroids is poor.

ICI, immune checkpoint inhibitor; PD-1, programmed cell death 1; PD-L1, programmed cell death ligand 1; PMR, polymyalgia rheumatica; RS3PE, remitting seronegative symmetrical synovitis with pitting edema.