Hi everyone -

I'm currently enrolled in a clinical trial that centers around tumor imaging and selective RT dose deescalation for lymph node tumors in certain circumstances. I wrote and mentioned some details about it and my upcoming decision on deescalation in a thread started about HPV deescalation, but wanted to open a new one, to hopefully get some thoughts and answers.

Here are the details on the study and possibly deescalation of RT:
1. Tumor must be HPV+ - Mine is +ve
2. Tumor must have no hypoxia (low oxygen) within either the primary or secondary (Lymph nodes), by the 2nd hypoxia scan (1.5wks into treatment). This scan is a FMISO PET scan. - Mine has a spot of hypoxia on the primary (tonsil) which disappeared 1.5 weeks into treatment.
3. A early response PET scan (normal PET) will be taken next Monday to determine the response in the lymph node area. RO says that PET will be harder to see a definitive response in tonsil and BOT area, due to inflammation, but in the neck / lymph node area it is easier to see. If there is no activity in the lymph node area on the PET, I'd be a candidate for dose deescalation.

A dose deescalation would only occur in the area of the cancerous lymph nodes and would be from 70Gy to 60Gy. No change in dose occurs to the other side of the neck, top of chest, primary cancer site, BOT, or area around the lymph nodes with tumors in them. My 2 lymph nodes (stacked) were about 4cm, so a sizable part of my neck could have a dose deescalation.

3. If the dose is deescalated, a small neck dissection would occur to check the irradiated nodes for any residual cancer. Additionally, I could request a larger neck dissection, which encompassed additional lymph nodes. My RO says that adding the selective neck dissection allows us to confirm that the lymph node tumor has been completely irradiated and any remaining tissue is only scar tissue.

My RO seems to think that with my age, it makes sense to try to spare the dose to the jaw and neck in order to help reduce any longer term side effects (10-20yrs in the future). She seems confident that the neck dissection will allow them to know if there is any residual cancer in the area that had dose deescalation. While there still may be cancer cells floating around my body somewhere (that would have still received the full normal dose of RT), the area that would be getting less radiation would be checked after the RT has completed, to ensure that the dose deescalation did not compromise local control.

She also says that some cancer centers only use 60Gy on the neck/lymph nodes with mandatory neck dissection on it afterwards. She seems to equate 60Gy for lymph nodes + neck dissection and 70Gy and no neck dissection. Thoughts on that?

Also, she said some centers always do a neck dissection post RT, regardless of dosing.

The main questions/thoughts as I see it are:
1. Does a neck dissection allow for the proof of local control in a specific area? (ie the area which has received 60Gy vs 70Gy)
2. All dosing other than the 2 impacted lymph nodes would remain constant. To me, this would not indicate an increased chance of metastatic disease or a potential loss of local control - assuming that point 1 is true and local control in the 60Gy area can be established with a neck dissection. Thoughts?
3. Are there any longer term side effects that may come up in the 10-20yr time frame? The RO mentioned jaw issues, necrosis, and salivary issues as all potential ones. I wanted to see if anyone had issues that came up a significant period after RT was over.

I have to make a decision on the trial this week, so they can change the treatment protocol if necessary. I'm about 50/50 now. I see positive aspects to both sides, but am not sure what is the right answer (and unfortunately won't know what that is until 5+ years from now!)

Your doctors know best, and wonder if they are suggesting which way to go? From my view, most of the previous studies, statistics are not based on HPV status, which is different in biology, response, and prognosis, as you know, and its own entity, so it's hard to compare all the info out there, but there does seem to be a more aggressive type, recently identified as type B HPV, in one report, which may not mean much as yet.

I'll try to answer the questions from the numerical list off the top of my head, and questions prior to this not numbered, to what I understand or may not.

1. No. There are no guarantees, and there could other risk of spread indicators such as ECE, but will be identified during surgery, pathology or skip metasteses. There are over 300 lymph nodes in the neck anyway, most microscopic, so a neck dissection may not get them all. You say selective neck dissection, but that usually level II-V with the sparing of one or all of the structures..vein, nerve, neck muscle, so it may be less than that with a limited neck dissection, involving one level, no more than two.

2. Anything can happen. Cancer can go anywhere. I had a RND, and cancer was found in my neck muscle, and had several recurrences after that with "no lymohs" which is basically roaming cancer cells now that can go anywhere, and went to the elliptical layer of skin.

3. IMRT has been around since 2000, so who knows. There is risk of a secondary cancer due to radiation leakage, especially IMRT, for every 10 years. Side effects are acute, less than 3 months, and late stage, more than 3 months. There are longer known effects as your doctor mentioned.

a. That's a planned neck dissection, regardless if the are no obvious signs of cancer. Some studies show there is better control with a planned neck dissection vs watch and wait, until there is a recurrence.

b. For tumor kill the dose has to be over 50gy, and for the cervical neck usuallly about 60-62Gy is given. I don't know of anyone getting 70Gy for all areas. Each structure has a total dose toxicity, such as salivary gland, brain stem, brachial plexus, so IMRT dose paints those areas according to thier toxicity limits.

I hope this helps, but not really saying which direction to go. Chemo is another story, and I'm more afraid of that due to my negative reactions, but seems like you did the first dose, and hope all went well.

Thanks Paul for the info. It absolutely helps.

RO is suggesting to go for the deescalation in dose, but of course it is my decision.

You make an interesting comment on the 60-62Gy used for the cervical neck. Is that the standard total dosing for cervical lymph node tumors? It seems I am getting a total of 70Gy to the cervical neck lymph nodes, and this deescalation brings me down to 60Gy. It is possible that MKSCC or my RO uses 70Gy as a standard dose to both primary and secondary sites, while other centers use a lower dose to secondary cervical lymph nodes. Does anyone have more information on this?

I checked some of my records, and due to a recurrences in 2011, the RO indicated from my initial radiation that the bilateral neck has been treated, so that level V on the left neck received between 56Gy-63Gy depending on the proximity to level IV, so the brachial plexus was at its dose limit at 63Gy, and reiiridation was denied. I think the doses vary by site, patient, and may depend if surgery was done, induction chemo, concurrent radiation, N0 vs multiple nodes, and dose limits to nearby vital structures. I would think the tumors, involved node (s) would get the highest doses.

Andrew, there are some articles in the OCF newsfeed which you may be interested in reading. The articles discuss the trials and different sub types of oral cancer. There is so much that is not yet known about both oral cancer and HPV.

Best wishes!

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