Cyberknife vs IMRT

Portal Forums Lung/Thoracic Cancer Stereotactic Radiation Cyberknife vs IMRT

This topic contains 17 replies, has 6 voices, and was last updated by  onthemark 10 months ago.

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August 3, 2014 at 1:58 pm  #1265255    

kiddoctor

I am a physician, and my mid forties non smoking asian wife was diagnosed with ALK + stage IV NSCLC in Sept. 2010. She collapsed from a brain met and has had a remarkable recovery from where she started. Got standard chemo with carboplatin and alimta with good response. PET negative. Spent the next 22 months on Alimta with stable disease until renal issues forced a stop. Last Alimpta Feb. 2013. Has been off chemo for completely now for 16 months. Brain MRI stable with no tumor on multiple scans. Lung shows resolution of all nodes and single primary which shrunk down considerably. Since off chemo, very slow growth from about 9X12 mm spiculated to 13X14 mm and more rounded. Considering focused radiation with Cyberknife or IMRT of another sort. Will also rule out use of surgery via scope. Questions (assuming lesion is appropriate for this Rx): wife likes idea of Cyberknife with very short course vs IMRT which may be longer (unsure if this is true yet). CK not locally available, but IMRT is (not sure of type yet).1. If there any evidence favoring one over the other? 2 Does this sound like a reasonable consideration? 3. if minimally invasive surgery is available, any preference over focused radiation? Just looking for consensus, if any. Previous discussions are too old to use now.

August 3, 2014 at 2:23 pm  #1265258    
Dr West
Dr West

I’m sorry to hear of your wife’s diagnosis but am glad she has done so well.

My center has “stereotactic body radiation therapy” (SBRT), also known as “stereotactic ablative body radiation” (SABR), which is essentially the same cyberKnife platform of radiaiton given over 4-5 fractions. I can tell you that we readily favor SBRT/SABR over a longer course of intensity-modulated radiation therapy (IMRT) in patients who are getting a single small focus irradiated, but let me see if a radiation colleague can offer any actual data to speak to this.

One advantage of surgery is that you get tissue for doing any further molecular marker studies and/or just making sure that the histologic findings haven’t changed significantly from the initial biopsy. That said, you could also just biopsy the lesion before radiating it.

Good luck.

-Dr. West

August 3, 2014 at 3:05 pm  #1265259    

kiddoctor

Thank you so much for the incredibly fast reply. I am trying to find out what they use locally and it seems from their website that they use tomotherapy and 3DCRT, which seems like an older generation of treatment. While we have been doing most of our care locally, we have a relationship with Memorial in NYC and it looks like they use the Trubeam machine. Is that a similar platform to yours? Does it have the same short course (1-5 days) as Cyberknife? Am I correct in assuming this newer technology would be worth traveling a bit to access?

Thanks in advance!

August 3, 2014 at 6:34 pm  #1265262    
Dr West
Dr West

We need to get a radiation oncologist to provide input on details. We’ll ask Dr. Loiselle to comment.

-Dr. West

August 3, 2014 at 6:51 pm  #1265263    

kiddoctor

Again, my thanks. This site is amazing!

August 4, 2014 at 12:05 pm  #1265272    

Dr Loiselle

Hi kiddoctor –

With all of the acronyms flying around regarding modern era irradiation techniques, it can be hard to sort the wheat from the chaff.

In general, local control of lung tumors is improved with high dose, short course, highly focused radiation. The local control of relatively small, isolated lung tumors is in the range of 90-95% with doses of radiation in the range of 50-60 Gy delivered in three to five fractions. The local control of the same lesion with “conventionally fractionated” radiation is closer to the range of 50% with doses of roughly 60 to 80 Gy delivered in 30-40 fractions.

Thus, the most important consideration here is dose and number of fractions. The high dose treatment is typically referred to as being “stereotactic.”

Use of terms like 3DCRT and IMRT typically refer to the longer traditional dose/fractionation patterns, however, these are planning techniques which can be used to ultimately deliver both conventionally fractionated or high dose/stereotactic radiation.

More specifically in terms of equipment, modern systems are good. Varian’s truebeam, cyberknife, and elekta’s linear accelerators all can deliver high dose treatments well. At times, certain platforms such as cyberknife may offer some advantages. In most cases, you do not need to seek out one specific machine over the other.

I recommend meeting with your radiation oncologist and discussing these issues. Ask their experience with stereotactic radiation and the specifics of their equipment.

I hope that helps.

Dr Loiselle


Chris Loiselle, MD
Radiation Oncologist
Swedish Cancer Institute

Views expressed here represent my opinion, not those of GRACE or Swedish Cancer Institute. This information does not constitute medical advice and is intended to supplement and not replace medical information provided by your doctor.

December 20, 2016 at 9:30 pm  #1289571    

onthemark

I’m trying to understand the statement “he local control of relatively small, isolated lung tumors is in the range of 90-95% with doses of radiation in the range of 50-60 Gy delivered in three to five fractions. The local control of the same lesion with “conventionally fractionated” radiation is closer to the range of 50% with doses of roughly 60 to 80 Gy delivered in 30-40 fractions.”

in the context of an on-going canada-wide clinical trial Stereotactic Body Radiotherapy Versus Conventional Radiotherapy in Medically-Inoperable Non-Small Lung Cancer Patients (LUSTRE),

which started at the end of 2013 and is still recruiting.

It’s purpose is: A multi-centre randomized controlled open-label trial in medically inoperable patients with biopsy-proven early stage non-small cell lung cancer (NSCLC). Eligible and consenting patients will be randomly allocated to receive stereotactic body radiotherapy (SBRT) or conventional radiotherapy (CRT) in a 2:1 ratio. Radiotherapy will be administered as soon as possible following randomization and subjects will be followed for 5 years post-randomization for cancer recurrence, toxicity and survival. The primary outcome is local control (LC). The trial will be conducted at 16-20 clinical centres throughout Canada.

If the results for local control are as unambiguous and clear cut as Dr. Loiselle states then why bother with the clinical trial? It seems highly irresponsible to be subjecting people to treatment that is known to be inferior in the guise of a trial.

December 21, 2016 at 7:40 am  #1289572    
JimC Forum Moderator
JimC Forum Moderator

Hi onthemark,

I think you raise a very fair question. I can’t speak for the trial sponsors, but one rational might be that the trial population is limited to a very specific set of patients with minimal disease, for whom the results may be somewhat less dramatically different. But I suspect it’s more an issue of limited availability of the equipment necessary to deliver SBRT, and a resulting desire to see how important it might be to allocate funds to make that equipment more widely available.

I’d have to say, though, that I wouldn’t want to opt for conventional radiotherapy over available SBRT, all other considerations being equal.

JimC
Forum moderator


Jul 2008 Wife Liz (51/never smoker) Dx Stage IV NSCLC EGFR exon 19
4 cycles Carbo/alimta, 65% shrinkage
Tarceva maintenance
Mar 2010 progression, added Alimta, stable
Sep 2010 multiple brain mets, WBR
Oct 2010 large pericardial effusion, tamponade
Jan 2011 progression, start abraxane
Jun 2011-New liver, brain mets, add Tarceva
Oct 2011-Dx Leptomeningeal carcinomatosis; pulsed Tarceva
At rest Nov 4 2011
Since then: http://cancergrace.org/blog/jim-and-lisa

December 21, 2016 at 8:02 am  #1289573    

onthemark

Hi Jim,

Thanks for your answer but I respectfully say it is not really addressing the point I made head on. The full quote by your doctor here refers specifically to local control “In general, local control of lung tumors is improved with high dose, short course, highly focused radiation. The local control of relatively small, isolated lung tumors is in the range of 90-95% with doses of radiation in the range of 50-60 Gy delivered in three to five fractions. The local control of the same lesion with “conventionally fractionated” radiation is closer to the range of 50% with doses of roughly 60 to 80 Gy delivered in 30-40 fractions.”

The primary outcome of the clinical trial is local control. The differences sited by Dr. Loiselle (90-95% vs 50%) local control are enormous and could not possibly justify a clinical trial to test local control in lung cancer, in my mind at least. That would already be sufficient justification for investing in more machines. I am wondering if Dr. Loiselle can address this question. If the numbers sited were really justified or not.

December 21, 2016 at 9:19 am  #1289577    
Dr West
Dr West

I appreciate your desire for a physician to address your question, but the reason we have moved to the current system is that the faculty just don’t have the capacity to address individual clinical questions. The highest priority for GRACE is to have the faculty produce content that can reach and help the most people with broadly useful, general information, but it hasn’t been feasible or sustainable to have faculty be available on demand to address questions for a single person, as they are all physicians who need to prioritize the care of their own clinic patients — Dr. Loiselle has a busy clinic and treats patients nearly every day, while also trying to juggle his other commitments. For questions beyond the depth of what we’ve provided, we need to request that people discuss their specific concerns with their own physician/team.

Jim and Janine have been working mightily to bridge this gap, but we haven’t been able to work out a perfect solution, given how busy people are.

Thanks for understanding.

-Dr. West

December 21, 2016 at 10:16 am  #1289578    
catdander forum moderator
catdander forum moderator

Might I suggest you read specifically what outcomes for which the trial in Canada is looking. It may answer the question of why. Stereotactic body radiation of lung tissue might more easily cause pneumonitis. Maybe they’re looking at harm v benefit. Or looking at the areas of the lung that respond better or more safely. You can find most clinical trials worldwide on clinicaltrials.gov

Sincerely,
Janine

December 21, 2016 at 10:48 am  #1289579    

onthemark

As I wrote the primary outcome is local control. I did get info from clinicaltrials.gov

December 21, 2016 at 11:01 am  #1289581    
catdander forum moderator
catdander forum moderator

Does the “Purpose” of the trial give any insight? What trial is it?

December 21, 2016 at 11:35 am  #1289582    
JimC Forum Moderator
JimC Forum Moderator

Hi Janine,

This is the trial: https://clinicaltrials.gov/ct2/show/NCT01968941

My thought is that SBRT has only recently (past several years) been shown to be very effective and safe in this setting, but the sponsors wanted to compare it head to head versus conventional radiation in the same patient population in order to determine not only relative percentage of local control (stated as the primary endpoint), but toxicity and survival as well. The initial concern with higher dose radiation was damage to healthy tissue.

But since the sponsors have not stated that, we can only speculate.

JimC
Forum moderator


Jul 2008 Wife Liz (51/never smoker) Dx Stage IV NSCLC EGFR exon 19
4 cycles Carbo/alimta, 65% shrinkage
Tarceva maintenance
Mar 2010 progression, added Alimta, stable
Sep 2010 multiple brain mets, WBR
Oct 2010 large pericardial effusion, tamponade
Jan 2011 progression, start abraxane
Jun 2011-New liver, brain mets, add Tarceva
Oct 2011-Dx Leptomeningeal carcinomatosis; pulsed Tarceva
At rest Nov 4 2011
Since then: http://cancergrace.org/blog/jim-and-lisa

December 21, 2016 at 11:39 am  #1289583    
catdander forum moderator
catdander forum moderator

Thanks Jim, got it.

December 21, 2016 at 12:37 pm  #1289585    

onthemark

I quoted the name LUSTRE and the purpose from clinicaltrials.gov. in my first post. You have a lot of good information on the site.

I didn’t appreciate that you have moved to a current system that was different than in the past. Certainly the moderators here make an awesome contribution. I guess now any readers that hit upon this thread will know it is not a settled issue whether sbrt or conventional radiation is better for lung lesions in lung cancer in terms of local control. At least not by the researchers who are conducting the LUSTRE trial.

  • This reply was modified 10 months ago by  onthemark.
  • This reply was modified 10 months ago by  onthemark.
December 21, 2016 at 12:59 pm  #1289587    
JimC Forum Moderator
JimC Forum Moderator

As far as that trial in that population is concerned, it may be an open question until the trial results are reported. But other trials have demonstrated the superiority of SBRT described by Dr. Loiselle, for example: https://www.ncbi.nlm.nih.gov/pubmed/20805737

As I stated earlier, without a statement from the trial staff, we can only speculate as to their reasons for conducting this specific trial.

JimC
Forum moderator


Jul 2008 Wife Liz (51/never smoker) Dx Stage IV NSCLC EGFR exon 19
4 cycles Carbo/alimta, 65% shrinkage
Tarceva maintenance
Mar 2010 progression, added Alimta, stable
Sep 2010 multiple brain mets, WBR
Oct 2010 large pericardial effusion, tamponade
Jan 2011 progression, start abraxane
Jun 2011-New liver, brain mets, add Tarceva
Oct 2011-Dx Leptomeningeal carcinomatosis; pulsed Tarceva
At rest Nov 4 2011
Since then: http://cancergrace.org/blog/jim-and-lisa

December 21, 2016 at 2:14 pm  #1289588    

onthemark

Hi Jim,

Thanks for pointing out that paper, which is an early phase study (LUSTRE, the study I have been referring to is phase 3) of the same patient population; stage 1, medically inoperable.

I note that the difference found in the paper you posted at 3 years for local control was not statistically significant (P=0.1).

I discovered today that most, if not all, clinical trials will have a paper describing the purpose and context in detail of the trial before the final results are in.

Indeed LUSTRE has such a paper “Canadian Phase III Randomized Trial of Stereotactic Body Radiotherapy Versus Conventionally Hypofractionated Radiotherapy for Stage I, Medically Inoperable Non?Small-Cell Lung Cancer ? Rationale and Protocol Design for the Ontario Clinical Oncology Group (OCOG)-LUSTRE Trial”

In the abstract they write: “The primary outcome of the study is 3-year local control, which we hypothesize will improve from 75% with CRT to 87.5% with SBRT.”

Here CRT is conventional radiotherapy given according to the standard Canadian protocol in 3 weeks.

I guess it’s a complex calculation and not all forms of CRT are equivalent but the difference in expected local control they site (87.5% vs. 75%) based on all the information they have, including the earlier trial you posted, is not anywhere close to the 90-95% vs. 50% given above.

Then they write: “Despite widespread interest and adoption of SBRT, there still remains a concern regarding long-term control and risks of toxicity (particularly in patients with centrally located lesions). The OCOG-LUSTRE study is the only randomized phase III trial testing SBRT in a medically inoperable population, and the results of this trial will attempt to prove that the benefits of SBRT outweigh the potential risks.”

So the question is if the relatively small expected advantage in local control at 3 years outweigh the risk of later term complications.

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