Re: 29.9 mCi RAI - is a walking dose enough to do anything?

[Guest guest]

Thanks for posting this link . I think I've read it before, but

I'm out of the dense brain fog and it all seems to make much

more sense now.

Now I'm wondering if I should have pushed for 100 mCi dose,

which was what my endoc originally said she was going to do.

Can't change what's already happened, but I can know for next

time if there is one. If I have uptake on my Feb. follow-up scan, it

seems that I should have a larger dose than I did the first time.

(29 mCi)

Of course every case is different, but I wonder if that strategy

follows what Dr. Ain and Ian were getting at in these archived

posts that you pointed out?

dee

> Dear All -

>

> The question has come up with some regularity - should I go

for a higher RAI ablative dose, with all the possible side effects,

or can I accomplish the same thing with the less risky low 30 (or

> 29.9) mCi RAI?

>

> The following letter was on another listserv recently, in

response to a letter about the need for a second RAI ablation ....

>

> " I understand your feeling down about the outcome of your

treatment. Please know that this is fairly common (especially

after a low-dose (30 mci) treatment). My endo had me do the 30

mci

> treatment. My nuclear physician was against it saying that 86%

percent of patients he treated with a low-dose treatment required

another treatment. I wish in hindsight I had known better and

had

> a bigger dose.

>

> " In the end, I ended up having to have two additional 150 mci

treatments to get rid of a small piece of residual tissue. I think

the 30 mci did nothing but damage some healthy tissue and

then

> later on down the road it just couldn't ablate well.... " -

Norman (posted here with her permission)

>

>

> Because we always like to quote the professionals, below are

some additional citations to back up 's personal

experience (and lay opinion).

>

> -

> ==========================================

> From Dr. Ain ....

>

> It is a certainty that there is no consensus among nuclear

medicine or

> endocrinology physicians regarding the proper dose of I-131 to

use for

> treating thyroid cancer. Much of the reason for this is that most

> physicians base their treatment upon " custom " and previous

modes of

> practice, particularly if they do not spend a significant portion of

> their professional time dealing specifically with thyroid cancer

and do

> not actively do clinical or basic research in this field.

>

> It is important to note that there is no scientific or medical

basis to the use of 29.9 mCi I-131 doses. This custom arose

from the administrative rules of the Nuclear Regulatory

Commission, that

> any dose of I-131 exceeding 30 mCi must be administered as

an inpatient in the hospital (requiring greater effort

> by the physician, greater expense by the medical plan & /or

patient, and

> monitoring by a radiation health physicist). For purely logistic

and financial reasons, many physicians routinely adopted the

use of the 29.9 mCi dose. I consider this to be inappropriate

and

> contrary to good patient management.

>

> Sufficient studies have been published over the years to

document the need to administer sufficient I-131 to kill target

tissues (thyroid cancer and remnants). The principles have

been clearly

> defined

>

> Schlesinger T, Flower MA & McCready VR (1989) Radiation

dose assessments in radioiodine (131I) therapy. 1. The

necessity for in vivo quantitation and dosimetry in the treatment

of carcinoma of

> the thyroid. Radiother Oncol 14, 35-41.

>

> Low doses, such as those 0f 30 mCi or less, are usually

ineffective:

> 1. Maxon HR, SR, Hertzberg VS, Kereiakes JG, Chen

I-W, Sperling MI

> & Saenger EL (1983) Relation between effective radiation dose

and outcome of radioiodine therapy for thyroid cancer. New Eng

J Med 309, 937-941.

>

> 2. Ramacciotti C, Pretorius HT, Line BR, Goldman JM &

Robbins J (1982)

> Ablation of nonmalignant thyroid remnants with low doses of

radioactive iodine: concise communication. J Nucl Med 23,

483-489.

>

> Effectiveness can be variably interpreted by different

physicians.

> Many do not require completely negative I-131 whole body

scans and absence of thyroglobulin when hypothyroid to define

clinical success. Fortunately, there are some patients treated

with low

> doses of I-131 who may be effectively treated, particularly if they

have minimal disease and remnant to start with.

>

> It is my clinical practice to use 100 mCi as my " minimal " I-131

dose for initial ablation, using the clinical circumstances

(defined by the tumor pathology and the whole body scan

findings) to

> delineate which patient require higher doses (150 mCi or

greater). My practice is described in the following two references

>

> 1. Ain KB (1995) Papillary thyroid carcinoma: etiology,

assessment, and therapy. Endocrin Metab Clin N Amer 24,

711-760.

> 2. Ain KB (1997) Management of thyroid cancer. In: Diseases

of the thyroid (Braverman LE, ed.) pp. 287-317, Humana

Press,Inc., Totowa, N.J.).

>

> ThyCa members may wish to avail themselves of some library

work.

>

> The bottom line is to be aware of what literature is available

(articles can be quoted on both sides of every issue) and to

know that this literature should be weighed and evaluated, but

not

> accepted merely because it is " published. "

>

> **************PLEASE BE ADVISED**********************

> THE INFORMATION CONTAINED IN THIS COMMUNICATION

IS INTENDED

> FOR EDUCATIONAL PURPOSES ONLY. IT IS NOT

INTENDED, NOR SHOULD

> IT BE CONSTRUED, AS SPECIFIC MEDICAL ADVICE OR

DIRECTIONS. ANY

> PERSON VIEWING THIS INFORMATION IS ADVISED TO

CONSULT THEIR OWN PHYSICIAN(S) ABOUT ANY MATTER

REGARDING THEIR MEDICAL CARE.

> *************************************************

> B. Ain, M.D.

> Associate Professor of Internal Medicine

> University of Kentucky Medical Center

==================================================

==

> From Ian Adam ...

>

> To be strictly accurate, [using a higher RAI ablative dose] is far

from being one doctor's opinion. Here in the UK the Code of

Practice for the Protection of Persons Against Ionising

Radiations

> arising from Medical and Dental Use (1960) recommended

30mCi of 131I as top whack for going home, and described the

circumstances under which this value should be reduced to half

or one eighth.

> This is what I applied until new regs came out in 1982.

>

> This set the scene for RAI administration and for this reason

alone many

> patients were given 30mCi as their first dose.

>

> Now, 40 years on, there is a substantial body of data and

30mCi is used far

> less frequently.

>

> I don't read the journals the way I used to, but I can't remember

ever having

> seen research out there that favors lower dosages of RAI.

>

> Ian Adam

> Radiation Safety Officer

> The Institute of Cancer Research

> ====================================

>

> Abstract comparing single low doses of RAI with single higher

doses ....

>

> " CONCLUSION: High dose 131I is more efficient than low

dose for remnant ablation particularly after less than total

thyroidectomy. Results suggest that patients with differentiated

thyroid cancer

> should routinely have a total thyroidectomy followed by high

dose 131I (2775-3700MBq) for ablation of the remnant. "

(NOTE: 3700 MBq = 100 mCi - K.)

>

>