High-dose-rate brachytherapy monotherapy v. low-dose-rate brachytherapy with/out external beam radiotherapy for clinically localized PCa

[pjoshea13]

New Japanese study below.

"The actuarial 5-year biochemical failure-free survival rates (bNED) were 92.9% and 95.6% ... in the HDR-BT and LDR-BT groups, respectively, and it was 100% and 97.3% ... in the low-risk, 95.6% and 94.3% ... in the intermediate, 89.6% and 94.9% ... in the high-risk groups, and 93.1% and 94.9% ... in selected high-risk group excluding T3b-4 and initial PSA ≥50. IPTW correction also indicated no difference in bNED between LDR-BT and HDR-BT groups. LDR-BT showed a higher incidence of genitourinary (GU) toxicity grade ≥2 than that of HDR-BT in the acute phase and grade 1 toxicity in late phase. Acute GU toxicity grade ≥1 predicted late GU toxicity grade ≥2. External beam radiotherapy plus LDR-BT elevated GI toxicity than LDR-BT only group. Accumulated incidence of late grade ≥2 GU and GU toxicity was equivalent between HDR-BT and LDR-BT. No grade 4 or 5 toxicities were detected in either modality."

-Patrick

ncbi.nlm.nih.gov/pubmed/304...

Radiother Oncol. 2018 Nov 8. pii: S0167-8140(18)33544-8. doi: 10.1016/j.radonc.2018.10.020. [Epub ahead of print]

High-dose-rate brachytherapy monotherapy versus low-dose-rate brachytherapy with or without external beam radiotherapy for clinically localized prostate cancer.

Yamazaki H1, Masui K2, Suzuki G2, Nakamura S2, Yamada K2, Okihara K3, Shiraishi T3, Yoshida K4, Kotsuma T4, Tanaka E4, Otani K5, Yoshioka Y5, Ogawa K5.

Author information

1

Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Japan. Electronic address: [e-mail].

2

Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Japan.

3

Department of Urology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Japan.

4

Department of Radiation Oncology, National Hospital Organization Osaka National Hospital, Japan.

5

Department of Radiation Oncology, Osaka University Graduate School of Medicine, Japan.

Abstract

BACKGROUND:

To compare the outcome of high-dose-rate interstitial brachytherapy (HDR-BT) monotherapy and low-dose-rate brachytherapy (LDR-BT) with or without external beam radiotherapy (EBRT) for localized prostate cancer.

METHODS AND MATERIALS:

We compared 352 patients treated with HDR-BT as monotherapy (median follow-up time 84 months, NCCN risk classification; low: intermediate: high = 28:145:179) and 486 patients with LDR-BT with or without EBRT (90 months, 194:254:38). HDR-BT treated advanced disease with more hormonal therapy than LDR-BT. LDR-BT excluded patients with T3b-T4 tumor and initial PSA >50 ng/ml. Inverse probability of treatment weighting (IPTW) involving propensity scores was used to reduce background selection bias.

RESULTS:

The actuarial 5-year biochemical failure-free survival rates (bNED) were 92.9% and 95.6% (p = 0.25) in the HDR-BT and LDR-BT groups, respectively, and it was 100% and 97.3% (p = 0.99) in the low-risk, 95.6% and 94.3% (p = 0.19) in the intermediate, 89.6% and 94.9% (p = 0.26) in the high-risk groups, and 93.1% and 94.9% (p = 0.98) in selected high-risk group excluding T3b-4 and initial PSA ≥50. IPTW correction also indicated no difference in bNED between LDR-BT and HDR-BT groups. LDR-BT showed a higher incidence of genitourinary (GU) toxicity grade ≥2 than that of HDR-BT in the acute phase and grade 1 toxicity in late phase. Acute GU toxicity grade ≥1 predicted late GU toxicity grade ≥2. External beam radiotherapy plus LDR-BT elevated GI toxicity than LDR-BT only group. Accumulated incidence of late grade ≥2 GU and GU toxicity was equivalent between HDR-BT and LDR-BT. No grade 4 or 5 toxicities were detected in either modality.

CONCLUSION:

HDR-BT monotherapy showed an equivalent outcome to that of LDR-BT with or without EBRT for low-, intermediate- and selected high-risk patients. LDR-BT showed equivalent incidence of grade ≥2 late GI and GU toxicities and higher grade ≥2 acute GU toxicity as that of HDR-BT as a monotherapy.

Copyright © 2018 Elsevier B.V. All rights reserved.

KEYWORDS:

Brachytherapy; High dose rate; Low dose rate; Prostate cancer

PMID: 30416045 DOI: 10.1016/j.radonc.2018.10.020

[cesanon]

Am I getting this right?

High-dose-rate brachytherapy monotherapy is no better and maybe worse than low-dose-rate brachytherapy monotherapy?

Is that right?

[AlanMeyer in reply to cesanon]

The way I read the article, the two treatments had very similar outcomes. If you look at the comparison numbers, the first three comparisons showed a small advantage for LDR (possibly including EBRT) over HDR and the next two showed a small advantage for HDR. LDR patients had similar side effect severity to HDR but higher "GU" toxicities - though neither group had severe side effects (grade 4 or 5).

One surprise to me was that it appears that none of the HDR patients got supplemental EBRT whereas an unspecified number of the LDR patients did. I would have expected EBRT to be given to any patients, whether taking LDR or HDR, if tumor cells were suspected in surrounding tissue outside the prostate gland - but the full article may explain all that (For the low, low price of only $35.95 at the Elsevier website.)

Alan

[AlanMeyer]

I was treated in 2003/2004 with HDR_BT + 3D conformal EBRT + Lupron - apparently very successfully - in a U.S. National Cancer Institute clinical trial.

By happenstance, I was at the NCI Clinical Center Radiation Oncology Department today for my annual follow up and I asked the radiation oncologist where things were going in radiation oncology these days.

She said she thought that HDR was getting more attention again. It was on an up tick when I was treated, then it went down, and now its going up again. She said the other big issues that are attracting research are higher dose rate external beam therapy, like SBRT, and treatment of the prostate when the cancer is known to be metastatic.

Her own view on the latter question was that there may be particular circumstances where it makes sense to treat the prostate even though the disease is already metastatic, but if the burden of disease is outside the prostate, radiating the prostate is just going to add side effects with no real effect on the disease.

Alan