Metastases

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SBRT Doubles Pain Response Over Usual RT in Spinal Metastases

A 2-day course of high-dose stereotactic body radiotherapy (SBRT) doubles the complete pain response for patients with painful spinal metastases in comparison with conventional palliative radiotherapy. It is also safe and nondestabilizing, conclude researchers reporting a phase 3 Canadian trial.

“Conventional radiation has historically not achieved high rates of complete response to pain or long-term local control,” commented lead author Arjun Sahgal, MD. “So many years ago, we started building on the idea of using high-dose stereotactic body radiation for the spine.”

Sahgal, who is professor and deputy chief of radiation oncology at Sunnybrook Health Sciences Center, the University of Toronto, Ontario, Canada, explained that his team came up with a plan to use SBRT with 24 Gy in two fractions. This involves only two consecutive treatments, which is very convenient for patients. Conventional radiation requires five or more sessions.

“Now we have shown a doubling of the complete response rate to pain at 3 and 6 months compared with conventional palliative radiation, and patients appreciate fewer treatment sessions, too, so we are helping our patients financially,” Shagal told Medscape Medical News.

He presented the new results during the virtual annual meeting of the American Society for Radiation Oncology (ASTRO).

Patients enrolled in this trial had de novo painful spinal metastases with three or fewer consecutive metastatically involved spinal segments arising from a primary tumor causing pain that was scored at least 2 on the Brief Pain Inventory.

The median baseline worst pain score was 5 in a range of 2 to 10. The median total spinal instability and neoplasia score (SINS) was 7 in a range of 3 to 12, Sahgal noted. “The primary endpoint was complete pain response rate at 3 months,” Sahgal told a press briefing held within the context of the virtual meeting.

Patients were randomly assigned to receive either SBRT with 24 Gy delivered in two fractions over 2 consecutive days or conventional palliative radiotherapy with 20 Gy delivered in five fractions.

Initially, the trial was launched as a phase 2 study, but once investigators could demonstrate that accrual was possible, they converted the trial into a phase 3 study, Sahgal noted.

A total of 114 patients were enrolled in the SBRT arm; 115 patients were enrolled in the conventional radiotherapy arm. All were included in the intent-to-treat analysis. “We found that at 3 months, the complete response rate was 35% in the SBRT arm and 14% in the conventional radiation arm, and the difference was statistically significant,” Sahgal reported.

The complete response rate was sustained at 6 months. It remained at 32% in the SBRT arm and 16% in the conventional radiotherapy arm. There was also a reduction in the total SINS score at 6 months that favored the SBRT arm.

Adjusted for age, sex, performance status, primary cancer, and total baseline SINS, SBRT was almost 3.5-fold more likely to result in a complete pain response rate at 3 months and was about 2.5-fold more likely to yield the same response at 6 months

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SRS Instead of WBRT for Patients With Multiple Brain Metastases

Stereotactic radiosurgery (SRS) should replace whole-brain radiotherapy (WBRT) as the new standard of care for patients with four or more brain metastases, say researchers who report results from a randomized trial conducted in patients with four to 15 brain metastases

“SRS was associated with reduced risk of neurocognitive deterioration compared to WBRT, as demonstrated by a constellation of neurocognitive tests, individually or by composite scores,” said lead author Jing Li, MD, PhD, associate professor of radiation oncology and codirector of the Brain Metastasis Clinic at the University of Texas MD Anderson Cancer Center, Houston.

He was speaking at the American Society for Radiation Oncology (ASTRO) 2020 Annual Meeting, which was held online this year because of the COVID pandemic.

“The results from this phase 3 randomized trial strongly support the use of SRS in patients with four to 15 brain metastases to better preserve cognitive function and to minimize interruption of systemic therapy, without compromising overall survival,” said Li.

SRS is already the standard of care for patients with one to three brain metastases. Two previous phase 3 randomized trials showed that SRS was better at preserving cognitive function without compromising overall survival in comparison to WBRT.

However, there has been some controversy over the use of SRS for patients with multiple brain metastases, commented study discussant Sue S. Yom, MD, PhD, a professor in the Departments of Radiation Oncology and Otolaryngology–Head and Neck Surgery, University of California, San Francisco.

This study has shown “in a practice-changing manner that giving SRS can improve the quality of life of patients with metastatic disease,” she said.

Up to 30% of cancer patients develop brain metastases. Historically, these have been associated with poor overall survival, in the range of 1 to 4 months.

Reduces Cognitive Decline

The new trial involved 72 patients with four to 15 untreated, nonmelanoma brain metastases (up to 20 lesions were allowed at the time of treatment); the median number of brain metastases was eight. Most (83%) of the trial participants were White, nearly half were aged 60 years or older, and 58% were women.

Patients were randomly assigned to receive either SRS (15–24 Gy per Radiation Therapy Oncology Group protocol 9005) or WBRT (30 Gy in 10 fractions). On the basis of previous research, 62% of patients in the WBRT arm were also given memantine, a dementia drug that can help preserve cognitive function.

All participants completed neurocognitive testing, including testing of learning, memory, attention span, executive function, verbal fluency, processing speed, and motor dexterity, at enrollment and longitudinally.

The primary endpoints were Hopkins Verbal Learning Test – Revised Total Recall (HVLT-R TR) score and local control at 4 months. Secondary endpoints included overall survival, distant brain failure, toxicity, and time to initiation of systemic therapy.

In the primary endpoint analysis, at 4 months, the HVLT-R TR standardized z-score increased by +0.21 (standard error [SE], 0.27) for patients who received SRS, but it declined by –0.74 (SE, 0.36) for WBRT-treated patients (P = .041). On the basis

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