Utjecaj unosa joda na epidemiološka i kliničko - patohistološka obilježja karcinoma štitnjače

Jukić, Tomislav (2008) Utjecaj unosa joda na epidemiološka i kliničko - patohistološka obilježja karcinoma štitnjače. PhD thesis, Sveučilište u Zagrebu.

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Abstract

The role of iodine in the pathogenesis of thyroid cancer is complex and controversial. In 1996, The New law on obligatory salt iodination was introduced in Croatia with the increse in content of iodine per kg of salt from 10 to 25 mg. The influence of increased iodine intake on clinical and pathohistological characteristics of thyroid cancer was investigated. The patients with thyroid cancer treated at the Department of Oncology and Nuclear medicine «Sisters of Charity» University Hospital, Zagreb in two periods with diferent iodine intake were analyzed (1988.-1992., moderate iodine deficiency, n=132) and (2000.-2004., iodine sufficiency, n=334). The influence of increased iodine intake on pathohistology, papilllary to follicular cancer and female to male ratio, age at presentation, size and stage of differentiated thyroid cancer, and the incidence and mortality from thyroid cancer in Croatia were investigated. Mann-Whitney Test, χ2 Test, Fischer's Exact Test, One-Sample Smirnov-Kolmogorov Test, and trend analysis were used in statistical analysis. After the New law the «papillarization» of thyroid cancer was demonstrated in Croatia with the increase in number of papillary thyroid cancer patients, increase in papillary to follicular cancer ratio from 8.3 to 15.2 (p=0,107), female to male ratio from 3.7 to 4.9 in papillary thyroid cancer patients (p=0,325) and age at presentation from 41 to 51 years (p<0.001) in papillary thyroid cancer patients. Furthermore, the decrease in median size of differentiated thyroid cancer from 20 mm to 12 mm (p<0.001), and shift to less advanced tumor stages was demonstrated in iodine sufficiency period: the increase in T1 and decrease in T2, T3 and T4 tumors (p<0.001), resulting in lower proportion of patients with regional and distant metastases. In iodine sufficiency period the incidence of thyroid cancer has increased in Croatia 2.5 times in females and 2.2 times in males in comparison to mild iodine deficiency period. However, in the observed periods mortality from thyroid cancer has remained stable at low levels in man, and decreased in iodine sufficiency period in females. The proportion of patients with papillary thyroid microcarcinoma has increased from 22% in mild iodine deficiency period to 45% in the period after the new law (p<0.001). The increase in incidence of thyroid cancer in Croatia can not be attributed to increased iodine intake. It is primary caused by improved diagnostics. Due to wide use of ultrasound and fine needle biopsy more and more papillary thyroid cancers are detected in the earlier stages of disease with better prognosis and very low mortality rate. In favour of this is low mortality rate from thyroid cancer in Croatia, in both females and males, despite significant rise in the thyroid cancer incidence rate.

Abstract in Croatian

Uloga joda u patogenezi karcinoma štitnjače je kompleksna i predmet je rasprave. U Hrvatskoj je uvođenjem novoga zakona o obveznom jodiranju soli 1996. godine povećana količina joda s prijašnjih 10 na 25 mg kalij-jodida po kilogramu soli. Istražili smo utjecaj povećane jodne profilakse na epidemiološka i kliničko-patohistološka obilježja karcinoma štitnjače. Uspoređeni su bolesnici s karcinomom štitnjače liječeni u Klinici za onkologiju i nuklearnu medicinu KB «Sestre milosrdnice», Zagreb u petogodišnjem razdoblju prije uvođenja novoga zakona (1988-1992, umjereni nedostatak joda, n=132) i petogodišnjem razdoblju nakon uvođenja novoga zakona (2000-2004, dostatan unos joda, n=334). Istražen je utjecaj povećane jodne profilakse na patohistološka obilježja karcinoma štitnjače, omjer papilarni-folikularni karcinomi štitnjače, omjer žene-muškarci, dob novooboljelih, veličinu i proširenost novootkrivenih diferenciranih karcinoma štitnjače, te incidenciju i smrtnost od karcinoma štitnjače u Hrvatskoj. U statističkoj obradi korišteni su Mann-Whitney test, χ2 test, Fischer-ov egzaktni test, Kolmogorov-Smirnovljev test i analiza trenda. Nakon novoga zakona utvrđena je «papilarizacija» karcinoma štitnjače obilježena porastom broja papilarnih i omjera papilarni-folikularni karcinomi štitnjače s 8.3 na 15.2 (p=0,107), omjera žene muškarci s 3.7 na 4.9 kod papilarnog karcinoma štitnjače (p=0,325) i dobi novooboljelih od papilarnog karcinoma štitnjače s 41 na 51 godinu (p<0.001). U razdoblju dostatnog unosa joda utvrđeno je smanjenje medijana veličine diferenciranog karcinoma štitnjače s 20 na 12 mm (p<0.001) i pomak prema manje uznapredovalim stadijima bolesti: porast udjela T1 uz smanjenje udjela T2, T3 i T4 tumora (p<0,001) s posljedičnim smanjenjem udjela bolesnika s regionalnim i udaljenim metastazama. Udio bolesnika s papilarnim mikrokarcinomom štitnjače se povećao s 22% u razdoblju prije uvođenja novoga zakona na 45% u razdoblju nakon uvođenja novoga zakona (p<0.001). Incidencija karcinoma štitnjače u Hrvatskoj porasla je u razdoblju dostatnog unosa joda 2.5 puta u žena i 2.2 puta u muškaraca u odnosu na razdoblje umjerenog nedostatka joda, ali je smrtnost od karcinoma štitnjače u promatranim razdobljima ostala nepromijenjena u muškaraca, dok je u žena u razdoblju dostatnog unosa joda zabilježen pad smrtnosti. Porast incidencije karcinoma štitnjače u Hrvatskoj ne može se pripisati povećanom unosu joda već poboljšanoj dijagnostici. Zbog široke upotrebe ultrazvuka i citološke punkcije otkriva se sve više papilarnih karcinoma štitnjače u ranijim stadijima bolesti koji imaju dobru prognozu i izrazito nisku smrtnost. Tome u prilog govori i niska smrtnost od karcinoma štitnjače u Hrvatskoj u oba spola, usprkos značajnom porastu incidencije.

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