Treatment Patterns and Attrition in Metastatic Renal Cell Carcinoma: Real-Life Experience from the Turkish Oncology Group Kidney Cancer Consortium (TKCC) Database.

Introduction: Despite the rapid evolution in management of metastatic renal cell carcinoma (mRCC) over the past decade, challenges remain in accessing new therapies in some parts of the world. Despite therapeutic advancements, attrition rates remain persistently high. This study aims to assess the treatment patterns and attrition rates of patients with mRCC in oncology clinics across Turkey.

Patients and methods: Patients diagnosed with mRCC between January 1, 2008, and December 31, 2022, with first-line systemic treatment data, were retrospectively evaluated using the Turkish Oncology Group Kidney Cancer Consortium (TKCC) Database.

Results: The final analysis included a total of 1126 patients. The percentages of patients treated in the 2nd, 3rd, 4th, and 5th lines of therapy were 62.8%, 27.4%, 8.9%, and 2.1%, respectively. The drugs that were most commonly used in the groups were tyrosine kinase inhibitors (TKIs) (52.2%) and interferon (IFN)-alpha (43.3%) for the first line, TKIs (66.3%) and immunotherapy (IO) monotherapy (25.9%) for the second line, TKI (41.4%) and mTOR inhibitors (28.8%) for the third line, TKI (44.4%) and mTOR inhibitors (29%) for the fourth line, and IO monotherapy (37.5%) and TKI (25%) for the fifth line. For the first-line treatment, the primary cause of attrition was disease progression (66.4%), followed by toxicity (16.5%), death (11.2%), and patient preference (5.9%). The primary reason for attrition across all treatment lines was disease progression. Over time, the use of TKIs in first-line treatment increased, while IFN-alpha usage declined. IOs began to be utilized in earlier lines, predominantly in second-line treatment, though use of IO-based combination therapies remains limited.

Conclusion: This study underscores that despite significant progress in therapeutic options, the adoption of novel agents remains slow, and attrition rates are still high. These findings indicate a disparity in systemic therapy compared to developed countries.