Sunitinib is an FDA-approved therapy used in palliative treatment for metastatic kidney cancer. This therapy is available in the market since 2005, and high toxicities was observed in both Singapore and other Asian cohorts at conventional dosing. Dr Tan Min Han, a visiting Consultant at Medical Oncology and Cancer Genetics National Cancer Centre Singapore (NCCS), provides further details on Long-term Outcomes of Attenuated Sunitinib Dosing in an Asian Population. This 10-mins interview was conducted by Rachel Lim.
Rachel: How was this study conducted?
Tan: This study was conducted as a prospective registry at the National Cancer Centre from 2007 onwards to current, after we observed severe toxicities in our patients using conventional dosing of sunitinib. The challenge was to balance our subjective observations against the demands of structured data required to lift our work to an experience that could be generalized regionally to improve cancer care Following dose-attenuation, outcomes were systematically compared against outcomes from parallel centres prescribing conventional dosing. The results were that our dose-attenuated regimen was equally efficacious, while being safer in terms of reduced side effects.
R: What are some of the reasons toxicities occur during the treatment of renal cancer?
Tan: Toxicities occur because of off-target effects by the therapy. Targeted therapies still may have scattershot or collateral damage, resulting in these drugs having effects on tissues other than the cancer cells. These side effects may include fatigue, hair discoloration, hypertension and skin rash.
R: What is the importance of these particular findings? How will this affect the treatment of renal cancer?
Tan: Our findings allow us to improve patient care using a targeted therapy for kidney cancer, achieving lower toxicities, with equivalent cancer survival outcomes. It would also be considerably cheaper for our patients, saving each patient about S$1300 per month in treatment costs. Our regimen is now established as current standard of care in Singapore, based on our clinical observations of intolerably high toxicities based on conventional dosing.
R: What is the difference in the dosing regimen in this study as compared to what is usually done?
Tan: Conventional textbook dosing of Sunitinib begins at 50 mg daily. Our recommended practice of reducing the starting dose to 37.5 mg has become conventional national practice in Singapore, as a direct result of this study, and to our knowledge, this practice is already growing in Asia. This work shows the benefit of real world experience for a new cancer therapy collated across multiple centres.
About the Interviewee
Dr. Tan Min-Han is a medical oncologist who divides time between the hospital and the laboratory. He sees patients as a visiting consultant medical oncologist at the National Cancer Centre Singapore (NCCS), specializing in urological cancers and clinical cancer genetics. He is also a principal investigator at the Institute of Bioengineering and Nanotechnology. He completed his medical oncology fellowship training at NCCS, and completed his PhD in the molecular epidemiology of kidney cancer. Dr Tan's research interests centre on practical cancer diagnostics, with a special interest in circulating biomarkers. He has contributed over 70 original papers and is an inventor of several novel technologies. Additionally, his public health research interests focus on optimisation of patient care through data-driven modelling of clinical outcomes in a wide range of cancers. Dr. Tan is the lead editor for the Singapore Cancer Network (SCAN), a national practice framework for Singapore oncologists.