Higher Risk of Kidney Cancer Recurrence After Ablative Therapy

LOUISVILLE, Ky. — Minimally invasive ablative therapy for early kidney cancer had an increased risk of local and metastatic recurrence, which is associated with increased mortality, Swedish investigators reported.

The population-based study showed more than a four-fold increase in the risk of locoregional recurrence and almost a two-fold increased risk of metastatic recurrence when patients opted for local ablation instead of partial nephrectomy. However, the analysis showed a low rate of recurrence overall, whether patients had surgical or nonsurgical treatment.

The analysis also did not include data on treatment-related morbidity, which should figure into discussions with patients, reported Borje Ljungberg, MD, of Umea University, at the International Kidney Cancer Symposium.

“There is a higher risk for local recurrence and a higher risk for distant metastasis, and we show that in a total population-based study,” Ljungberg told MedPage Today, during a poster discussion session. “We have follow-up for when they die. We must inform the patients of the higher risk with ablative therapy.”

“We could have made it better if we had comorbidity and everything else,” he added. “We will do another study in the coming years where we look at comorbidity together with this, but still, ablation-treated patients have a higher risk of recurrence.”

The findings do not make a case for superiority of one treatment strategy over others but instead the need to discuss risks and benefits of the various treatment options with patients to facilitate informed decision making, said Ljungberg.

During almost 5 years of follow-up, the overall recurrence rate was relatively low, about 4%, for locoregional and distant recurrence, said poster discussant Arpita Desai, MD, of the UCSF Helen Diller Family Comprehensive Cancer Center in San Francisco. Patients need a complete picture of risks and benefits of treatment options for renal cell carcinoma to make an informed decision about how they want to proceed.

Discussions about surveillance versus treatment for newly diagnosed renal masses are separate from the issue addressed in the study, Desai added. All the patients in the Swedish study had decided they wanted some form of treatment. The decision involved ablation versus surgery.

The analysis involved 2,751 kidney tumors diagnosed from 2005 to 2018 in 2,701 patients in the National Swedish Kidney Cancer Register. All the patients were treated by partial nephrectomy or some form of ablative therapy. The primary outcome was time to local/distant recurrence or death according to the type of treatment.

During a mean follow-up of 4.8 years, 111 local recurrences (4.0%) and 108 distant recurrences (3.9%) were identified. Subsequently, 24 (21.6%) patients with local recurrence died during a mean follow-up of 3.2 years, and 56 (51.9%) of patients with distant metastasis died during a mean follow-up of 2.8 years. That compared with a 7.5% mortality among patients without local or distant recurrence, Ljungberg reported.

Patients who opted for ablative therapy had a hazard ratio of 4.31 versus partial nephrectomy for local recurrence (95% CI 2.79-6.66, P

For distant recurrence, ablative therapy was associated with a hazard ratio of 1.91 (95% CI 1.11-3.28, P=0.018) versus partial nephrectomy. However, other factors also influenced the risk:

• Age: HR 1.04 (95% 1.01-1.07, P
• Calendar year of treatment: HR 0.87 (95% CI 0.79-094, P
• Male sex: HR 1.63 (95% 1.06-2.52, P=0.026)
• Tumor size: HR 1.01 (95% CI 1.00-1.03, P=0.015)
• Stage T1b at diagnosis: HR 1.85 (95% CI 1.11-3.08, P=0.018)
• Stage T2-T4 at diagnosis: HR 2.71 (95% CI 1.25-5.88, P=0.011)
• Papillary/chromophobe histology: HR 0.55 (95% CI 0.34-0.90, P=0.016)

The findings suggest that partial nephrectomy is the preferred treatment for most patients with operable RCC, said Ljungberg. They also imply that ablative therapy may be best for frail patients and those with significant comorbidities, the researchers stated.

The study did not examine recurrence rates by different types of ablative therapy, noted Priyanka Chablani, MD, of the University of Pittsburgh Medical Center, co-moderator of the poster session. Recurrence rates might vary by the type of intervention. Limited data exist on recurrence rates for newer types of ablative interventions, such as radiotherapy.

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