CT/PET scan versus CT contrast

malkin

I have a question about PET versus CT scans.

My metastatic (to liver) anal SCCA responded well to systemic chemotherapy (6 rounds of cisplatin and 5FU).  The PET scan following the completion of chemo shows no uptake at all (SUV zero everywhere).  CT scan shows 65% decrease in the linear size of the liver mets (RECIST criteria) whereas the primary anal tumor (~4cm originally) has disappeared completely (both in CT and PET scans).  The original scans (before starting chemo) showed consistency between CT and PET with PET manifesting SUV uptakes between 5 and 15 at the various lesions showing up on the CT scan.  But now PET is showing nothing as CT still shows liver spots measuring 2cm to 0.8cm in linear dimensions.

My oncologist and radiation physician are absolutely ecstatic aboout the PET scan showing nothing, finding it to be a very significant positive developement.   My hepatic surgeons, who still consider me a non-candidate for liver resection surgery (because of the "bad distribution" of the remaining liver lesions), tell me that they attach NO significance to PET scans, saying that "PET often goes cold" following chemotherapy, and according to them this means nothing.  

I am obviously very confused.  Both scans were taken together three and a half weeks after the end of thge last round of chemo.  Everything I read seems to suggest that in general PET is more reliable than CT, but the surgeons seem not to agree.  I am now waiting for immunotherapy since I simply cannot ake any more cisplatin (the procol limit has been reached for me).

Does anyone have any comment on this situation?  I am only 44 and am obviously extremely scared.  I will appreciate hearing from people who are knowledgeable about the reliability of CT versus PET in cancer diagnostics.

mp327

malkin

Your question is a good one.  However, since I'm not a radiologist, I cannot comment as to the reliability of one vs. the other.  I do know that my medical oncologist preferred PET scans for awhile after my treatment ended, but switched me to CT scans at some point in my follow-ups.  That said, I do believe it had more to do with insurance coverage than anything else, as getting PET scans covered by insurance became an issue. 

eihtak

Malkin.....

It does seem that different physicians do not agree on this question as I have heard both sides as well, but also feel that as Martha said, much has to do with insurance at times too.

I am approaching 6 years post treatment for Stage 3b anal cancer, however did have mets to my lung almost 2 years ago. My only PET scan throughout was at my 1 yr post initial treatment. My doctor has chose the reliability of routine CT scans.....sometimes with contrast and sometimes without. I am due to see him in January so will ask his current opinion at that time.

Also, of interest, I was treated both times with Cisplatin / 5FU although at a higher dose for mets. It was considered to switch to carboplatin as the side effects may be less but decided to tough it out. I don't however think that drug would be an option for (either of us) if needed again as it is also a platinum-based agent and may be included in that max dosage....not sure on that though???

This journey can be very confusing.....I will keep you in my thoughts and wishes for health as you continue to move forward.

katheryn

malkin

Thank you both Martha and

Thank you both Martha and Katheryn, all comments help.  Insurance is not an issue for me, and I can have as many CT or PET (or any other scan) as the physicians decide to have.  My question really is about the fficacy of ehe treatment, and how one knows if one is getting 'cured' or not.  (I understand that the party line is that stage IV cancer has no 'cure', but this is just semantic-- if I live another 30-40 years without being 'cured', I will take that.)

What I really want to know is people have experienced a situation where the PET scan shows literally nothing (no SUV above background whatsoever), but the cancer is still very much there.  I started with a PET scan in June which lit up all over (with high SUV counts), and now, in late November, PET shows nothing!

I realize that this is potentially good news, and am trying to figure out how good this 'good news' really is.

Are there others out there who experienced the same situation as me?

mp327

malkin

I would view your PET scan results as good news since there were no hot spots.  One of the hardest things for me during this journey has been to believe that a "clean" scan means that my cancer is gone and not hiding somewhere in my body, undetectable by a scan.  I think it's human nature to have a morsel of doubt or two.

horsepad

I had stage 4, mets to the

I had stage 4, mets to the liver, and had a PET scan one month after treatment.  Hot spots lit up in my lympth nodes, liver but original tumer was gone.  After 3 months a CT scan with contrast showed everything cleared up but something showed up in lympth nodes and liver that oncologist felt was dead cancer cells.  I had a liver resection to remove dead cells and wait and see on lympth nodes.  I never had another PET scan but have had several CT scans with contrast.  I have been cancer free for 5 years and had my last CT scan in August.  My oncologist differed in their opinions on CT/PET scans.

tanda

CT/PT

I had CTs and a PET/CT for staging, but have only had CT's since end of treatment.  My oncologist said that PETs light up all over and it is difficult to tell what may be a problem and then would require further investigation. My initial CT showed some spots in the lung and liver, which were thought to be nothings; they mostly disappeared or remain stable in subsequent CTs.

Mollymaude

PET

I think PET is more sensitive and reliable. It seems to be the gold standard for metastisis. Like a previous poster said, CT may be showing dead cells or scarring. The first CT I had after treatment still showed "something" in anal canal but both my oncologists were incredibly confident cancer was gone just from the digital rectal exams. I think your oncologists are right. Your oncologists probably have more experience than surgeons with this type of situation.

malkin

PET vs CT

Thank you all so much for your informative posts.  Everything I read also tels me that in general PET/CT is more reliable than CT contrast, particularly when it shows negative results (i.e. cold).  It is possible that surgeons rely much more on the CT scan since they use CT to guide their surgery to the right spot.

 

I have a question for 'horsepad' who like me also had stage iv cancer.  What was the treatment you had?  Mine was intense six rounds of FU5 plus cisplatin which completely melted away my primary anal tumor (both on CT and PET as well as on digital rectal exam) and greatly shrunk my liver tumors on CT (and supprssed their PET activity completely).  

 

I remain keenly interested in hearing from as many people as possible.  I basically have no support on a personal level at all, and am fighting things on my own.  It is frustrating to see how little the whole medical system knows about metastatic anal cancer.  I have now read essentially all technical articles on the subject (around 100 altogether-- almost all essentially statistical clinical studies), and a large fraction of them start with the meaningless sentence 'Anal cancer is a rare malignancy...' as if this is relevant at all!

tanda

CT/PET vs CT

If you are waiting for immunotherapy (would it be a clinical trial) you will probably be scanned again.  You may want to seek a second opinionn on the scans...just for your peace of mind.  Where are you currently being treated?

Despite the  recommendations in the NCCN Guidelines, it seems that there is a huge variation in how people are being followed -up in terms of what type of scan, and at what intervals. Guidelines, of course, are just guidelines and have to be applied to individual cases; other factors (insurance, Drs preferences, etc) also come into play.

 

Mollymaude

Rare malignancy

Dear Malkin, I am so sorry to hear you don't have much support. I don't have any experience with stage 4 cancer, my tumor was large but no spread to lymph nodes. I think the reason "rare cancer" is relevant is that many of our providers have less experience treating anal cancer than we would like. My GI doctor had never seen it before (he was very young) and basically gave me the feeling my prognosis was terrible when it was actually good. My primary care provider is a PA and he's only seen it three times. My radiation oncologist had only treated 10-15 people with anal cancer. After reading as much as you have on the subject you know a lot- sometimes you've read things your doctors haven't. Don't be afraid to bring copies of articles, ask questions, and get  second opinions.

The other reason "rare cancer" works against us is that there won't be as much research money for anal cancer as there is for more common ones, and it's harder to do research with fewer subjects. 

malkin

Mollymaude said:

Rare malignancy

Dear Malkin, I am so sorry to hear you don't have much support. I don't have any experience with stage 4 cancer, my tumor was large but no spread to lymph nodes. I think the reason "rare cancer" is relevant is that many of our providers have less experience treating anal cancer than we would like. My GI doctor had never seen it before (he was very young) and basically gave me the feeling my prognosis was terrible when it was actually good. My primary care provider is a PA and he's only seen it three times. My radiation oncologist had only treated 10-15 people with anal cancer. After reading as much as you have on the subject you know a lot- sometimes you've read things your doctors haven't. Don't be afraid to bring copies of articles, ask questions, and get  second opinions.

The other reason "rare cancer" works against us is that there won't be as much research money for anal cancer as there is for more common ones, and it's harder to do research with fewer subjects. 

Rare

It is indeed true that oncologists and other physicians know little about anal cancer in general and metastatic anal cancer in particular.  I am yet to meet a physician who is as well-informed as I am about the disease.  In fact, NCCN has essentially no guidelines for treating metastatic anal cancer, which is hard to fathom, given that it is increasing by a few percent every year in its prevalence of new cases.  What I meant in my earlier post was that knowing that it is a rare malignancy is no comfort if you happen to have it-- then it is not rare AT ALL as far as you are concerned (and these are the likely people reading these articles)!

There is little scholarly research on anal cancer at the cellular or molecular level, most studies are clinical and based purely on after the fact collection of data in specific hospitals.  Even the much-touted conection to HPV is statistical-- around 80% of the SCCA patients have HPV, but the other 20% do not.  This correlation is obviously not causal since the estimated number of HPV-infected people in USA is close to 100 million, and the number of new anal cancer cases are in a few thousands.  Obviously, HPV is not the full story, and may not even be the main story.  All researchers (Cathy Eng of MD Anderson is probably the most well-known name-- she was involved in a well-publicized nivoluman phase II trial) working on it are clinical oncologists, not molecular biologists.  Clinical oncologists collect data and produce statistics, this is not really research leading to understanding.

But for all of you following this discussion, I should emphasize that local anal cancer is among the most treatable malignancies that there are.  Nigro protocol, a very standard chemo-radiation protocol with roughly a 5-week duration, cures it completely in more than 95% of the cases.  If any physician tells you otherwise, he/she is ignorant.  The important thing is to ensure that it has not metastacized, meaning that you must have a careful staging scan done before the beginning of the treatment.  Metastatic anal cancer should generally be treated with intense systemic therapy involving platinum-based chemicals.

 

Unfortunately, my case started as metastatic right from the beginning although I had no symptoms at diagnosis (or even now-- nine months after my diagnosis).  All my symptoms are from the very serous chemotherapy I have had over a 6-month period.

 

I am fighting with the insurance company and the hospital in order to get immunootherapy.  Currently, there is no clinical trial accepting metastatic anal cancer patients.  Of course, the immunotherapy (involving nivolumab) costs hundreds of thousands of dollars, and no one can afford to get it personally.

My personal confusion in this matter is about the reliability of PET/CT versus CT contrast scans.  My PET scan shows no SUV activity anywhere following 6 rounds of intense chemotherapy, and I am trying to find out if others have had similar experience.  I have looked at the scans myself very carefully and two different radiologists produced reports saying that all SUV uptakes in the first diagnostic staging scan have disappeared ("no hypermetabollic activity")-- I want to know how good this good news is!  I am asking to see if there are others who have had such PET reports which later on turned out to be false.

 

tanda

Malkin

There are a number of anal cancer patients on the site BLOGFORACURE.org.  Many have completed treatment  and some survivors  were/are Stage 4.I believe a few are in immunotherapy trials; some at  MDAnderson and, at least one at Northwestern (an arm of the MDA trial)

There are some immunotherapy trials for  HPV positive Cervical cancer patients and probably for HPV positive head and neck cancer patients. T(their initial treatment is somewhat similar to ours (chemoradiation with cisplatin) I wonder if they would accept an HPV positive anal cancer patient.

Where do you live?  Where are you being treated?

Ouch_Ouch_Ouch

Scans & NCCN.

1. PET scans involve getting radiation injected into you where CT scans do not. I remember getting an explanatory card to take home with me in case I was stopped during a police radar set-up that detected the radiation. IF I remember correctly, PET scans detect hot spots of accumulated radiation, but does not have as fine a resolution of tissues as a CT scan does. PET scan tells where to look while CT scan tells what is there. I think I remember reading where insurance companies often impose a lifetime limit on the number of PET scans a customer can receive.

RadiologyInfo.org is the information site of the Radiological Society of North America, Inc. (RSNA) and the American College of Radiology (ACR). It gives a lot of information about radiation tests, treatments, and conditions. You can find information on the various scans at this website.

* Article on contrast mediums - http://www.radiologyinfo.org/en/info.cfm?pg=safety-contrast
* Article on CT scan of abdomen & pelvis (also check the CT of chest) - http://www.radiologyinfo.org/en/info.cfm?pg=abdominct
* Article on PET scan - http://www.radiologyinfo.org/en/info.cfm?pg=PET
* Anal cancer specific treatment info is here - http://www.radiologyinfo.org/en/info.cfm?pg=anal-cancer-therapy

2. The NCCN "Anal Carcinoma" guideline does offer information on metastatic anal carcinoma, both in the "ANAL" and "MS" pages. It may not be as much as malkin would like (as we all would like!), but as page MS-13 points out, this is still a relatively rare cancer with only a limited amount of data. The current edition is "1-2017 -- November 23, 2016".

3. After I was finished with treatment (9 July 2014), my oncologist told me that I was only her 6th anal cancer patient and that she had treated no reoccurences as yet. (She is the one who initially told me that I was stage 2 while the radiation oncologist said I was stage 3A or 3B - inquinal nodes weren't biopsied. He was correct and he treated me for 3B. He's also the kind one who sat me down one day to tell me that I was not to blame for the disease, that it was a part of the human condition. He was a real teddy bear! If you are in the lower Hudson Valley, I recommend Dr Eanelli.)

malkin

Ouch_Ouch_Ouch said:

Scans & NCCN.

1. PET scans involve getting radiation injected into you where CT scans do not. I remember getting an explanatory card to take home with me in case I was stopped during a police radar set-up that detected the radiation. IF I remember correctly, PET scans detect hot spots of accumulated radiation, but does not have as fine a resolution of tissues as a CT scan does. PET scan tells where to look while CT scan tells what is there. I think I remember reading where insurance companies often impose a lifetime limit on the number of PET scans a customer can receive.

RadiologyInfo.org is the information site of the Radiological Society of North America, Inc. (RSNA) and the American College of Radiology (ACR). It gives a lot of information about radiation tests, treatments, and conditions. You can find information on the various scans at this website.

* Article on contrast mediums - http://www.radiologyinfo.org/en/info.cfm?pg=safety-contrast
* Article on CT scan of abdomen & pelvis (also check the CT of chest) - http://www.radiologyinfo.org/en/info.cfm?pg=abdominct
* Article on PET scan - http://www.radiologyinfo.org/en/info.cfm?pg=PET
* Anal cancer specific treatment info is here - http://www.radiologyinfo.org/en/info.cfm?pg=anal-cancer-therapy

2. The NCCN "Anal Carcinoma" guideline does offer information on metastatic anal carcinoma, both in the "ANAL" and "MS" pages. It may not be as much as malkin would like (as we all would like!), but as page MS-13 points out, this is still a relatively rare cancer with only a limited amount of data. The current edition is "1-2017 -- November 23, 2016".

3. After I was finished with treatment (9 July 2014), my oncologist told me that I was only her 6th anal cancer patient and that she had treated no reoccurences as yet. (She is the one who initially told me that I was stage 2 while the radiation oncologist said I was stage 3A or 3B - inquinal nodes weren't biopsied. He was correct and he treated me for 3B. He's also the kind one who sat me down one day to tell me that I was not to blame for the disease, that it was a part of the human condition. He was a real teddy bear! If you are in the lower Hudson Valley, I recommend Dr Eanelli.)

updates and questions

Thank you all for your support, which I do need all the time. A few updates and questions below.

I have now studied many technical clinical papers on the role of PET scan in anal cancer.  The clinical consensus seems to be that a clean cold PET scan post-therapy (as I have) is strongly correlated with good prognosis.  Most studies involve very few metastatic anal cancer patients (since there are simply so few of us), but still this correation between complete metabolic PET response and good prognosis seems to be universal.  This gives me some hope.

I have meanwhile started on immunotherapy.  I get a one hour nivolumab infusion every other week, and so far it has gone well.  No side effects whattsoever.  

I have a few questions, which I hope could be answered by people.  I look forward to hearing from you.

(1) Is there anybody in this discussion board who has had nivolumab?  If so, please let me know how it worked out.  I am obviously very anxious.

(2) I am completely asymptotic nine months after my stage IV anal cancer (metastatic to the liver) diagnosis.  My original pain in the bottom and bleeding disappeared right after the beginning of my chemo.  Other than chemo side effects, I have no other issues: no pain, no fatigue, no weight loss, no loss of appetite. I am intersted in knowing how common this is.  Are most people asymptotic nine months after their diagnosis with the tumors only showing up on scans and biopsies?

(3) Six cycles of systemic chemotherapy (5FU+cisplatin given 120 continuous hours in each cycle) have completely eliminated my primary anal tumor which measured 4cm before chemo began.  It is now gone completely on the CT scan, on the PET scan, and on the digital rectal exam.  I have no symptoms of anal tumors at all.  All I have is a little tenderness in the bottom, not a pain or swelling, but if I press hard, it hurts slightly.  Do others have similar experience of tenderness once the tumor is gone?

(4) Is there anybody whose anal tumor disappeared just with chemotherapy without any radiation at all?  Of course, the chemotherapy I have had (720 hours of continuous infusion into my heart) is so intense that it would probably by itself kill most people. It almost killed me, and I am a strong 44-year old who is very healthy otherwise.

I thank you all in anticipation of your comments.  Thanks.