Papillary and follicular carcinomas
For the rest of the talk I’m really going to treat papillary and follicular carcinomas together as far as treatment decisions are concerned. The prognostic factors are similar for staging, and although it has traditionally been said that the outcome in follicular cancer is worse than the outcome in papillary cancer, oftentimes it’s not clear if it relates to the difference in the tumor type or if it’s more properly accounted for by these risk factors. But important prognostic risk factors, in terms of staging or particularly patient age – older being worse from a viewpoint of outcome – tumor size, multifocality within the thyroid gland may be a moderate factor for risk. Tumor histology; we’ve talked about some of the very specific variant forms already. The presence of local invasion into surrounding neck structures. Cervical node metastases in papillary thyroid cancer certainly are not a terrible risk factor, and in fact many studies would suggest that there is little difference in outcome related to the presence or absence of cervical nodes, but there may be some factor. Clearly, distant metastases are important. This just shows the importance of age. Most of the deaths from papillary thyroid cancer, from differentiated thyroid cancer, occur in patients who acquire the disease at an older age. Read more…
There have been several staging systems that have been popularized for papillary thyroid cancer. It’s sort of one of these things about standards now. Everybody likes standards so much, and that’s why they make so many different ones. I counted at least eight different papillary thyroid staging systems. I’m just going to mention two of them. Certainly a TNM staging system has been widely adopted. I think that the important thing to look at here is that it covers all different forms of thyroid cancer, including medullary and anaplastic. You’ll notice that for differentiated follicular cancer, for patients less than 45, the only differentiating factor is the presence of absence of metastases. Using the TNM patient, any patient under 45 who does not have metastatic disease is going to be classified as stage I, if they do have it stage II. For age over 45, both the presence of tumor size, local spread and nodal or metastatic involvement obviously is associated with increasing staging. This just shows that the staging system this is not quite the TNM system but it is very close to it and you can see that the staging system does fairly well in papillary, follicular, medullary and anaplastic. You know, all anaplastic cancer is stage IV, in terms of predicting survival. Another system that has been used was proposed by Masoferre who has done yeoman work in the area of the natural history of thyroid cancer, and they used four stages. I happen to like this system because clinically I find it very easy. Stage I is folks with tumors less than 15 mm in size and do not have any other features. Stage II are kind of intermediate size tumors as well as patients with metastases or patients with multifocality within the thyroid gland. Stage III are patients who have local invasion into surrounding structures of the neck, and stage IV are patients with distant metastases. Again, this staging system also works quite well in terms of predicting recurrence, which tends to rise with staging as well as death from cancer, which tends to rise from stagin with stages.
What about the treatment factors, in terms of the outcome for treatment in thyroid cancer? I think the take home message from the staging system is that we can identify a group of patients who are at fairly low risk – those at young age with small or moderate size tumors who are going to do quite well – and we can identify another higher risk group – those who are older, those who have evidence of multifocality or spread. What about frequent factors? Delay in treatment – I’m not going to talk about – but Masoferre’s document the thing about thyroid nodules is that they can be present for a long time and ignored for much of that time. But Masoferre has documented that delay in terms of treating a known thyroid nodule is associated with a worse outcome. Other treatment factors, extensive surgery, the use of 131 iodine and degree of TSH suppression. I’ve got sort of an algorithm in the notes and let’s kind of go through this very quickly. The first decision that we need to make is extensive surgery. Should one have a total thyroidectomy, or a lobectomy? The point here is that if you anticipate the need for using radioiodine then the patient should certainly have a total thyroidectomy done.
There may be a group of patients – and this is a very very controversial and debated issue among surgeons – there may be a group of patients, those who are young with small tumors, for whom lobectomy is enough. In these patients you might do a lobectomy and if the pathology confirms that the tumor is indeed small, that none of these other histologic factors are present, then for that type of a patient putting the patient on thyroxin suppression and continuing to observe them is probably sufficient. However, if they are going to need more aggressive treatment following the lobectomy then you’d want to recommend having completion of that thyroidectomy done. For those of you who cannot read, the orderly is sort of wheeling one patient out of the OR and another one in, and the caption reads, “Next”. An example of the very same procedure when done correctly.