5-Year Outcomes of Proton Beam Therapy Similar to IMRT

Comparative Analysis of 5-Year Clinical Outcomes and Patterns of Failure of Proton Beam Therapy (PBT) versus Intensity-Modulated Radiotherapy (IMRT) for Prostate Cancer in the Postoperative Setting (2020)

"Abstract

Purpose: Although proton beam therapy (PBT) is a rapidly expanding modality to treat prostate cancer (PC) as compared to intensity-modulated radiotherapy (IMRT), data comparing disease control outcomes and patterns of failure in the post-prostatectomy setting remain substantially limited.

Methods: All patients who underwent post-operative IMRT or PBT to the prostate bed only at a single institution were included (2009-2017). Endpoints included biochemical failure (BF) (using institutional and recent cooperative group trial definitions), local failure (LF), regional failure (RF), distant failure (DF), and all-cause mortality. A case-matched cohort analysis was performed using 3-to-1 nearest-neighbor matching; multivariable Cox proportional hazards modeling (MVA) estimated hazard ratios for disease-related outcomes by treatment modality.

Results: Of 295 men, 260 were matched (n=65 PBT, 195 IMRT); after matching, only age at diagnosis (p<0.01) significantly differed between cohorts. At a median follow-up of 59 months, BF (institution-defined), LF, RF, DF, and mortality rates were 45% (n=29), 2% (n=1), 9% (n=6), 9% (n=6), and 2% (n=1) for PBT, and 41% (n=80), 3% (n=5), 7% (n=13), 9% (n=18), and 5% (n=9) for IMRT (all p>0.05). RT modality was not significantly associated with BF on MVA using institutional or cooperative group definitions (all p>0.05), nor with LF (p=0.82), RF (p=0.11), DF (p=0.36), or all-cause mortality (p=0.69). Patterns of failure were qualitatively similar between cohorts (DF: bone, retroperitoneal nodes, lung).

Conclusions: In this single institution, case-matched analysis, PBT yielded similar long-term disease-related outcomes and patterns of failure to IMRT in the post-prostatectomy setting."
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A quick googling turned up a news article stating PBT was $60,000 more than IMRT per patient according to insurance claims. I guess we'll see if either (1) PBT costs come down or (2) other and longer-term follow-ups give an edge to PBT over IMRT and SBRT that justifies its higher cost. I know the toxicity profiles of these RT modalities differ somewhat. Case-matched studies like this one are difficult to conduct, however.

Djin

JNF said...
When I first came on the board we had several men who had or were using PBT. But that all dropped off when the reimbursements changed and I can’t remember one use reported on the board in the past few years.

I hadn't thought about this until you mentioned it, but you're right--there used to be all sorts of posts from guys that either had proton therapy or were considering it. We don't see that anymore, so I appreciate your context about reimbursements changing.

Good point Ed. Not much about microwaved balls either.

Your recent video of the turkeys was wonderful. You can’t find one in a Georgia right now as it is hunting season. They know when to hide.

JNF said...
Good point Ed. Not much about microwaved balls either.

Your recent video of the turkeys was wonderful. You can’t find one in a Georgia right now as it is hunting season. They know when to hide.

thanks jack. i see those turkeys at the trailhead and they are especially bold if i'm early. probably lucky i didnt get attacked .

Yes, I agree that this report confirms similar findings reported earlier.

Thanks, Djin. Interesting piece!
David

(I know nothing about turkeys)

AS you are correct that many centers have opened in the last 15 years. One proton association website shows 37 now in operation in the US with 2 in the planning/construction stage, so we should continue to see more centers opening in the next 5 to 10 years. But the growth will be nothing like was seen between 2000 and 2018 when the number of centers more than doubled.

The last 15 years has shown the most increase in new centers. However, during most of that time it was being used for PCa (and lung and breast cancers), but that diminished greatly in mid 2018 when the reimbursement rules changed and the ASTRO standard of care for PCa changed. After all, if the professional society of radiologists suggest against its use, why would Medicare and commercial insurance and union plans cover it? I remember a couple of people on this board in the last year look into it, but none reported using it. Interesting you note the other sites and I look forward to looking at those.

Similar reimbursement actions have also reduced proton treatment for lung and breast cancer, so it isn’t just PCa at issue. These are the three most cancers treated by radiation so if you lose a significant portion of the largest markets there will be changes. In 2015 it was estimated that at many proton centers PCa procedures contributed from 25-50% of revenues.

I just read a few commercial insurances company reimbursement guidelines for PBT and found that PCa, breast, lung, pancreatic, bone and spinal cancers and several others are not reimbursed citing multiple studies in each showing no advantage of PBT over IMRT/IGRT/SBRT/brachytherapy and other current photon treatments.

In mid 2018 both the Kaiser Health News and the New York Times reported on the subpar financial and utilization situation of many centers. At that time about one third were in serious loss positions and restructuring their massive debt. A few had filed for bankruptcy protection, and or sold to other institutions. This happened in Atlanta before the center even opened due to a $150 million cost overrun forcing Emory out of the ownership of the center. A common thread was that utilization was only 50-75% of expectations. A listed cause was significantly reduced utilization for lung, breast and prostate cancer due to reimbursement limitations from Medicare and commercial and union insurance. Couple this with the terrible construction and financial situation with the Emory University Atlanta Center and the development of additional centers is expected to slow according to many reports I have read. One potential center in New York, which surprisingly has never developed a center, is for the development of a mini-center costing about $50 million and very narrowly treat certain cancers that have proven to be best treated by proton. As far as I can tell the center is still in the planning stage.

For PCa we have many well established effective radiation options that are continually improving in cancer control and reduced treatment side effects. That Proton has not proven to be better than photon should not be seen as a problem or limitation. And, as a person that likes the health care choices we enjoy in the US, I fully support a person that wants to self pay for a more expensive procedure. Their body, their money their choice.

Of course, Mayo is/was charging the same rate for proton prostate treatment as IMRT since that was the reality of the situation for them. They have more resources than the average treatment center to make that decision.

My RO was from Mayo and he said there was no evidence that proton was better than IMRT for prostate treatment when I consulted with him initially based on current studies at the time. He was glad to refer me if I wanted to investigate further.

ASA - I suspect the Proton difficulty will be that all radiation may go to much shorter treatment schemes if the recent history proves out and proton will still be too expensive on a relative basis. Most IMRT machines can do SBRT now so there are thousands of lower cost machines/facilities in driving distance to most people so the HiTech centers will remain just that for other cancers, etc. IMHO of course.

The (MedStar) center where I received SBRT recently installed a proton radiation facility. Its primary use according to their 'advertising' will be for brain and pediatric cancers.
I asked the radiation oncologist who is in charge of SBRT and IMRT therapies at that center, and he confirmed that their proton facility is unlikely to be used for prostate cancer treatment.