ATLANTA—Adjuvant radiotherapy may offer a high rate of local control with increased progression-free survival without significantly harming quality of life in patients with high-risk stage 3 renal cell carcinoma (RCC), data presented at the American Society for Radiation Oncology’s 55th annual meeting.

“This is a controversial area,” said lead study investigator William Baquero, MD, an attending physician at the VIDT Centro Medico-21st Century Oncology, Buenos Aires, Argentina. “We don’t have any treatment guidelines for adjuvant radiotherapy in these renal cell carcinoma patients. I was surprised that we had such good results in terms of clinical response.”

Dr. Baquero, who presented the study findings at the meeting, said the five-year overall survival (OS) rate for stage 3 RCC does not exceed 65%. In addition, he noted that in the presence of poor prognostic factors there tends to be an increased rate of local relapse affecting the quality of life in this patient population.

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He and his colleagues studied 30 patients with stage 3 RCC who underwent radical nephrectomy and received adjuvant radiotherapy. The five-year local control rate was 93%, and only two patients relapsed in the retroperitoneum.

“Patients with bad prognostic factors should be offered this treatment,” Dr. Baquero told Renal & Urology News. “In general, these patients aren’t offered postoperative radiotherapy but they should be.”

The mean time to local relapse was 67 months (range 36-91 months). The five-year OS rate was 80%, and the metastasis-free survival rate was 83%. Distant metastases developed in five patients (17%); the mean time to metastases was 68 months (range 9-91 months).

Patients received an external beam radiotherapy dose of 45-50 Gy to the nephrectomy bed, with 10-15 Gy Boost to micro/gross disease (1,8-2 Gy/fx).

The mean age of the patients was 57 years (range 36-73 years) and the mean follow-up was 71 months (range 14-91 months). Ninety percent of the patients had clear cell RCC, with infiltration of the capsule in 93% of cases. In addition, 53% had perinephric fat invasion and 20% had renal vein involvement.

The median radiation dose was 55Gy (50- 59.4Gy) and the reported toxicities included nausea (Grade 0-I) in 70% of the patients and Grade II-IV nausea in 30%. Vomiting (Grade 0-I) occurred in 80% and Grade II-IV vomiting occurred in 20%.   Dr. Baquero said acute diarrhea (Grade 0-I) occurred in 96.6% and Grade II-IV in the remainder (3.3%), chronic gastrointestinal and hepatic toxicity were reported (Grade 0-I) 100%.

The study was limited by its retrospective design, Dr. Baquero noted. Prospective trials assessing new techniques and various fraction sizes of radiotherapy in selected patients may be warranted, he added.