There is no single accepted standard of care that is highly effective for these patients, and complete responses are rare.
Unfortunately, the response rates and complete responses in advanced disease are >80% and 40-60%, respectively.
Circulating tumour cells rapidly vanished after surgery or chemotherapy in most patients whose treatments were judged as effective including complete response and partial response by imaging diagnosis.
3, 4 Since the first clinical study in 1990, ECT has been reported as highly effective, with complete response rates between 60% and 70% and objective response (complete and partial response) rates of approximately 80%, 1– 5 especially when the standard operating procedures for ECT were followed.
Panobinostat, administered orally at a MTD of 20 mg, 3 days a week on a 28-day cycle, showed to be safe and effective, achieving complete responses, partial response, stable disease with ongoing improvement, and progression on treatment, respectively, in 2, 4, 2, and 1 patient.
Despite reported effective responses with complete response in most patients treated, relapses are frequent and may occur rapidly.
In contrast, PET/CT was not effective at predicting complete response to treatment with an accuracy of only 50%.
The MDA criteria take into account the fact that the structure of bone rarely heals such that the bone has the same appearance as the original even if treatment was significantly effective (complete response).
Certainly it is our hope that future therapies will be so effective that complete responses will be seen regularly and the therapeutic bar will be raised even higher, but until that time, it is important to consider PFS a legitimate measure for studies of single agents and drug combinations for the purpose of community usage but also, in some cases, for marketing approval.
SBRT was effective enough to achieve complete response of the disease, and the patient had developed no evident recurrent disease so far.
