Over 75s with RCC represent unique subpopulation
medwireNews: Older adults with metastatic renal cell carcinoma (RCC) are less likely to receive treatment, and have a poorer outcome than their younger peers, research suggests.
"Our results implicate the possibility that older adults receive fewer lines of systemic therapy," say the research authors, led by Sumanta Pal (City of Hope Comprehensive Cancer Center, Duarte, California, USA).
Indeed, the researchers found that the proportion of patients in their study receiving no therapy increased with increasing age, at 21% of patients under the age of 55 years, 26% of patients aged 55-64 years, 32% of patients aged 65-74 years, and 70% of patients aged 75 years and older.
"Further, our data suggest that older adults may be more prone to discontinue therapy as a consequence of toxicity as opposed to disease progression," the researchers add in the Journal of Geriatric Oncology.
They identified 219 patients with metastatic disease from an institutional database of 562 patients with RCC.
The majority of patients were male (72%), had clear cell cytology (82%), had received prior nephrectomy (70.9%), and were characterized as having intermediate-risk disease according to Memorial Sloan-Kettering Cancer Center criteria.
In all, 36.1% of patients were younger than 55 years of age, 35.2% were aged 55-64 years, 19.6% were aged 65-74 years, and 9.1% were aged 75 years or older.
The median survival of the overall cohort was 23.7 months, and it was considerably shorter in patients aged at least 75 years, at 12.5 months, compared with 26.4 months for those younger than 75 years.
Patients aged 75 years or older also received significantly fewer lines of therapy than younger patients, at an average 0.45 lines versus 1.57 lines in patients younger than 55 years of age.
The percentage of patients discontinuing therapy due to disease progression was lower among the 75 years and over age group, compared with the other groups, whereas the percentage discontinuing due to toxicity was higher.
"These data underscore the need to better understand both the safety and efficacy of targeted therapies in older patients," say Pal et al.
They suggest several reasons why older adults may gain less benefit from targeted agents, including a distinct disease biology, such as a higher frequency of certain mutation aberrations and clear cell histology, and physiologic differences, such as comorbidities, and decreased liver mass and cytochrome P450 enzyme content.
medwireNews (www.medwirenews.com) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2013
By Lucy Piper, Senior medwireNews Reporter