A 68-year-old woman with recurrent cutaneous SCC (CSCC) over the past two years felt an axillary mass beneath in her left armpit while showering. A CT scan of her chest revealed an 8 cm axillary nodal conglomerate, two enlarged supraclavicular lymph nodes and several pulmonary nodules suggestive of metastatic disease, confirmed by biopsy of the left axillary mass.
The patient experienced significant progression on the first-line alkylating antineoplastic agent. The tumor committee recommended immune checkpoint inhibitor therapy. A restaging PET/CT scan showed significant reduction in size of the axillary nodule mass and significantly reduced uptake in the pulmonary nodes.
However, increased SUV uptake was noted in several vertebrae, including the T2, T4, and L2, along with several lytic lesions.
What are the possible reasons for the new bone lesions?
Should this patient continue her current treatment?