Association of the Placement of a Perirectal Hydrogel Spacer With the Clinical Outcomes of Men Receiving Radiotherapy for Prostate Cancer

Abstract

IMPORTANCE Perirectal spacers are intended to lower the risk of rectal toxic effects associated with prostate radiotherapy. A quantitative synthesis of typical clinical results with specific perirectal spacers is limited. OBJECTIVE To evaluate the association between perirectal hydrogel spacer placement and clinical outcomes of men receiving radiotherapy for prostate cancer. DATA SOURCES A systematic search was performed of the Cochrane Central Register of Controlled Trials, MEDLINE, and Embase for articles published through September 2019.STUDY SELECTION Studies comparing men who received a hydrogel spacer vs men who did not receive a spacer (controls) prior to prostate radiotherapy. DATA EXTRACTION AND SYNTHESISVia random-effects meta-analysis, group comparisons were reported using the weighted mean difference for continuous measures and the risk ratio for binary measures. MAIN OUTCOMES AND MEASURESProcedural results, the percentage volume of rectum receiving at least 70 Gy radiation (v70), early (Յ3 months) and late (>3 months) rectal toxic effects, and early and late changes in bowel-related quality of life on the Expanded Prostate Cancer Index Composite (minimal clinically important difference, 4 points). RESULTSThe review included 7 studies (1 randomized clinical trial and 6 cohort studies) involving 1011 men (486 who received a hydrogel spacer and 525 controls), with a median duration of patient follow-up of 26 months (range, 3-63 months). The success rate of hydrogel spacer placement was 97.0% (95% CI, 94.4%-98.8% [5 studies]), and the weighted mean perirectal separation distance was 11.2 mm (95% CI, 10.1-12.3 mm [5 studies]). Procedural complications were mild and transient, occurring in 0% to 10% of patients within the studies. The hydrogel spacer group received 66% less v70 rectal irradiation compared with controls (3.5% vs 10.4%; mean difference, −6.5%; 95% CI, -10.5% to -2.5%; P = .001 [6 studies]). The risk of grade 2 or higher rectal toxic effects was comparable between groups in early follow-up (4.5% in hydrogel spacer group vs 4.1% in control group; risk ratio, 0.82; 95% CI, 0.52-1.28; P = .38 [6 studies]) but was 77% lower in the hydrogel spacer group in late follow-up (1.5% vs 5.7%; risk ratio, 0.23; 95% CI, 0.06-0.99; P = .05 [4 studies]).Changes in bowel-related quality of life were comparable between groups in early follow-up (mean difference, 0.2; 95% CI, -3.1 to 3.4; P = .92 [2 studies]) but were greater in the hydrogel spacer group in late follow-up (mean difference, 5.4; 95% CI, 2.8-8.0; P < .001 [2 studies]).

Quality of life more than 10 years after radiotherapy for localized prostate cancer—impact of time after treatment and prescription dose

“…In contrast to the three-dimensional conformal technique, image-guided and intensity-modulated radiotherapy is regarded as the current standard [ 12 ]. Application of these techniques will most probably allow to improve QoL results, as also been shown by rectal spacers that considerably decrease the rectal dose and improve QoL [ 2 , 13 , 14 ].…”

Extreme Hypofractionation with SBRT in Localized Prostate Cancer

“…In another prospective study of 42 patients treated for PCa with SBRT [65], a dosimetric analysis was performed comparing patients in whom hydrogel spacer was used, noting that the maximum dose received by the rectum is lower in patients in whom hydrogel spacer was used, as well as an improvement in most rectal dosimetric parameters, these results being corroborated by other studies [66,67]. A meta-analysis, published in 2020 [68], with 1011 patients, evaluated the role of hydrogel spacer in 486 patients who had hydrogel spacer inserted. The rectal separation in the hydrogel spacer group was wide, with a median distance of 11.2 mm between the rectum and prostate, while the complications related to the placement of hydrogel spacer were mild and transient, with incidence varying between 0% and 10%, and 66% less rectal irradiation described in the hydrogel spacer group at the isodosis of 70 Gy (rectum V70) compared to the controls, (p = 0.001).…”

Successful Use of Absorbable Hydrogel Rectal Spacers (SpaceOAR) Before Salvage Radiation Therapy After Previous Prostate Cryotherapy

“… 20 In addition, over the last several years the use of absorbable hydrogel spacers (eg, SpaceOAR) have been used to further improve the therapeutic window. 22 These hydrogel spacers have been demonstrated to consistently reduce rectal doses 10 , 11 (>90% patients achieving reduction in rectal V70 of at least 25% in a randomized trial 11 ) and improve quality of life 23 , 24 with little toxicity (rate of grade 1 or greater rectal acute adverse events or procedure adverse events through 6 months similar to the control group in a randomized trial 11 ) for men receiving high-dose radiation therapy for prostate cancer, and these spacers have achieved Food and Drug Administration clearance and widespread acceptance.…”