Radiation safe as salvage option after HIFU

Radiation is a well-tolerated and effective salvage option following primary high-intensity focal ultrasound (HIFU) for the treatment of localized prostate cancer, according to findings from a single-institution retrospective analysis.

Among 28 patients who received salvage radiotherapy at University College London Hospitals (UCLH) between 2010 and 2018, at a median follow-up of 43 months after either conformal radiotherapy or intensity modulated radiotherapy, 12 of the 28 reported no or very small problems with overall urinary function using the Expanded Prostate Cancer Index Composite for Clinical Practice (EPIC−CP) symptom tool.

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Data on late toxicity using Patient-Reported Outcome Measures (PROMs) with salvage radiotherapy in this setting are limited. EPIC-CP is a validated and clinically relevant tool to assess and quantify side effects from pelvic radiotherapy.

“In our center, men who relapse after focal therapy who then have significant disease on repeat MRI staging and biopsy are offered ‘salvage radical treatment,’ which may be either radical prostatectomy or salvage radiation,” said lead investigator Reena Davda, MD, consultant in uro-oncology, UCLH, NHS Foundation Trust, London. She presented the data at the Genitourinary Cancers Symposium in San Francisco.

“Although the cohort is small, late toxicity measured using PROMs is comparable to toxicity reported in men receiving radiation therapy as their primary treatment for localized prostate cancer,” she said. “We have a unique cohort at UCLH as we have a long-established focal therapy practice and therefore have long-term data related to failure and outcomes following radical salvage treatment.”

All 28 men in the series had undergone focal therapy as their primary treatment for prostate cancer. Gleason score at diagnosis in the cohort was 3+3 in four patients, 3+4 in 22 patients, and 4+3 in two patients. All patients had recurrence as demonstrated by multiparametric magnetic resonance imaging and biopsy, with a median PSA level of 6.6 ng/mL.

“Many men in the cohort were extensively treated with the use of whole-gland HIFU, and almost half of the cohort underwent focal therapy again following relapse after the first HIFU treatment,” Dr. Davda said. Nine of the 28 underwent focal HIFU, six had whole-gland HIFU, seven had focal and redo focal, one had focal and redo whole gland, and five had whole gland and redo.

Patients received 74 Gy to the prostate. Four patients received additional pelvic lymph node irradiation. Three men received conformal radiotherapy and 25 underwent arcing intensity-modulated radiotherapy. Median age at radiation was 67 years.

The time from primary initial HIFU to requiring salvage treatment ranged from 17 to 120 months. The median time from initial HIFU to requiring salvage treatment was 59 months.

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Late bowel and urinary toxicity was measured by EPIC-CP, on which lower scores indicate a more favorable health-related quality of life, with a score of 0 being the best possible score and 12 being the worst possible score.

Overall urinary function was graded as “no problem” in eight men, “very small problem” in four, “small problem” in seven, “moderate problem” in five, and “big problem” in four. The average urinary incontinence symptom score was a 1 and the average urinary irritation/obstructive symptom score was 0.5.

Rectal pain or urgency was graded as “no problem” in seven, “very small problem” in two, “small problem” in two, “moderate problem” in four, and “big problem” in one. The average bowel symptom score was 2.5.

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Seven patients each also graded increased frequency and overall bowel movements as “no problem.” Four considered increased frequency and two considered overall bowel movements a “very small problem,” and one and three, respectively, a “small problem.”

Biochemical relapse occurred in two of the 28 patients.

“The small number of patients who have relapsed after treatment in our cohort have been managed with hormone therapy, and we have not recommended further focal therapy or local salvage in this small number of patients,” said Dr. Davda.

Dr. Davda is a consultant/adviser to and has received travel, accomodations, and expenses from Janssen. Several of her co-authors have disclosures with pharmaceutical companies; for full disclosures, go to bit.ly/salvageafterHIFUdisclosures.