A differential response to sunitinib: sustained systemic response paralleled by intra-dural progression in the spine. Should standard response criteria be reviewed?

Sustained systemic response paralleled with ovarian metastasis progression by sunitinib in metastatic renal cell carcinoma: Is this an anti-angiogenic potentiation of cancer?

Metastatic renal cell cancer is associated with poor prognosis and survival and is resistant to conventional chemotherapy. Therapeutic targeting of molecular pathways for tumor angiogenesis and other specific activation mechanisms offers improved tumor response and prolonged survival. A 48-year-old, female patient presented with large right renal mass with features suggesting of renal cell cancer without metastasis on contrast enhanced computed tomography (CT). Right radical nephrectomy was done. After 9 months of surgery, she got metastasis in lung, liver and ovary. The patient received sunitinib via an expanded access program. After eight 6-week cycles of sunitinib, a reassessment CT scan confirmed an excellent partial response with the almost complete disappearance (90%) of liver and lung metastasis but the adnexal mass had increased in size (>10 times) and the possibility was thought of second malignancy. Excision of the mass performed. Histopathology of the mass depicted metastatic renal cell cancer. There is possibility of a ‘site-specific anti-angiogenic potentiation mechanism’ of malignancy in relation to sunitinib based upon the preclinical studies, in reference to the index case. Regression of one site with concurrent progression is possible. The exact mechanism of site-specific response, especially organ specific progression by vascular endothelial growth factor inhibitors in metastatic renal cell cancer warrants further study.

Progression of intramedullary metastasis during perioperative cessation of sunitinib

BACKGROUND

A 57-year-old woman presented with metastatic renal cell carcinoma (RCC). She was enrolled in a clinical study, in which she received two cycles of neoadjuvant sunitinib therapy followed by cytoreductive nephrectomy. Her primary tumor and rib metastasis showed a good response to neoadjuvant therapy; however, after surgery, the patient developed neurologic symptoms, including flaccid paraparesis with paresthesia and hypoesthesia. MRI of the brain and spine revealed a leptomeningeal lesion at the T12-L1 space, which was presumed to have progressed during the 3-week treatment-free perioperative period. The patient underwent radiation therapy for the intramedullary lesion 1 month later, and sunitinib therapy was subsequently reinstated. After 6 months, her extracranial lesions remained stable and the intramedullary lesion was undetectable on MRI.

INVESTIGATIONS

CT of the chest and abdomen, bone scan, kidney and liver function tests, measurement of serum levels of calcium, electrolytes and lactate dehydrogenase, CBC, MRI of the brain and spine.

DIAGNOSIS

Progression of a central nervous system metastasis linked to the interruption of neoadjuvant sunitinib therapy.

MANAGEMENT

Neoadjuvant sunitinib therapy followed by cytoreductive nephrectomy for the primary RCC; radiation therapy for the intramedullary lesion, followed by reinstatement of sunitinib therapy owing to a good clinical response observed in the extracranial lesions.