Thyroid cancer is admittedly the commonest endocrine malignancy often detected among young patients and frequently among the women. In most populations, the median age of its detection tends to be quite low, actually below 40 in most cases. It is currently the fastest growing cancers among women. Despite the fact that the cancer is still quite rare, it continues to be increasingly on the rise among women across the globe and especially pregnant women. Most experts are not quite certain on the causes despite the fact that they have been able to identify the risk factors at play.
Essentially, there are four main types of thyroid cancer: Follicular, papillary, medullary and anaplastic. Papillary and follicular thyroid cancers are jointly referred to as differentiated thyroid cancer since their prognosis is more favorable relative to the other types. Among most young women, their pregnancy periods are usually accompanied with differentiated thyroid cancer. The management of this type of cancer poses risks due to the concerns of maternal and fetal health. With most women experiencing rises in differentiated thyroid cancer during pregnancy with a prevalence rate of 14 per 100,000, it has become necessary to discern the management of the ailment (Smith, Danielsen, Allen & Cress, 2003)
Differentiated thyroid cancer (DTC) has a higher incident among women within their reproductive ages. It has long been speculated that the association between human chorionic gonadotropin (HCG), estrogen and DTC exists. Numerous studies have pointed out an association between high parity and the risk of DTC in pregnant women (Kravdal, Glattre, & Haldorsen, 1991). However, the data on the association between DTC and estrogen seem to be gravely inconsistent with some studies indicating a pro-proliferative effect on the thyroid cancer cell lines occasioned with estrogen while other studies point at estrogens stimulatory effect on the adenomatous and normal thyroid only (Lee et al., 2005)
Clinical data also conflicts; one study revealed a high risk of DTC infection among women exposed to oral contraceptives containing estrogen with another reporting no association between DTC and usage of exogenous hormones Data on the effect of HCG on DTC tends to be very discordant and non confirmatory. Despite the fact that rising levels of HCG during pregnancy tends to stimulate the production of thyroid hormones, there has not been any coherent evidence that links HCG and DTC. On the basis of women cohort using fertility drugs for treatment, there was no association observed between use of HCG and DTC. Simply put, according to available epidemiologic data, high parity and the risk to DTC are associated; but there is still some lack of clarity with regard to outcomes of DTC diagnosed at pregnancy (Mack, Preston-Martin, Bernstein, Qian, & Xiang, 1999).
As a result of the overt female to male ratio in the incidence of thyroid cancer, particularly the differentiated cancers, within their reproductive years, epidemiological studies have seriously focused on the role of reproductive exposures among women. Most studies have generally come up with findings that concur with the role of reproductive exposures. There is a minimal contribution of reproductive factors in the etiology and development of thyroid cancer among women. In fact, several case control studies have revealed increased risk with abortion or miscarriage, particularly during the first pregnancy (McTiernan Weiss & Daling, 1987). Arguably, this is one of the most recognized reproductive risk factor for differentiated thyroid cancer among women.
There is an elevated risk of developing thyroid cancer among women who use lactation suppressants and this risk seems to increase with the number of pregnancies in which the suppressants are used (McTiernan, Weiss & Daling, 1984).
Risk factors for thyroid cancer
A risk factor refers to anything that plays a role in influencing a person’s chance of contracting a particular disease. Admittedly, there are several risk factors behind any particular cancer. It must however be emphasized that risk factors do not tell everything, rather, they illuminate, to a less degree, the probable cause of the disease. It must also be asserted that the absence of a risk factor does not absolve one from contracting a particular cancer. Experts have also come to the conclusion that having one or several risk factors increases the chances of one contracting the cancer. In the case of thyroid cancer, there are a number of risk factors that have been reported and they will be discussed below.
Gender and age have been noted to be among the leading risk factors of thyroid cancer. Globally, women are three times likely to be affected by thyroid cancer compared with their male counterparts. On the issue of age, thyroid cancer can develop at any particular age. However, two thirds of the cancer cases are more prevalent between ages 20 and 55.On the other hand, anaplastic thyroid cancer tends to be diagnosed after 60 year of age (Braunstein, 2011).
Exposure to radiation has scientifically been proven to be a risk factor in the development of thyroid cancer. The main sources of the radiations could emanate from medical treatments, nuclear weapons and fallouts from power plant accidents. Moderate levels of exposure to radiations increase the risks of follicular and papillary cancer. Such sources include:
• Low to moderate doses of x- ray treatments that were used to treat children with tonsils, acne ad other head and neck pains
• Persons who have received radiation therapy for lymphoma in the head and neck are more inclined to develop follicular and papillary cancer.
• Early exposure to radioactive iodine especially at childhood increases the risk of contracting follicular and papillary cancers.
There are certain types of thyroid cancer that are normally associated with genes. Actually, 20% of patients suffering from medullary thyroid cancer (MTC) tend to possess an abnormal gene that facilitates the development of the disease (Cooper et al, 2009). The gene is usually passed to offspring. The thyroid cancer that emanates from genetic abnormality is referred to as familial medullary thyroid carcinoma. In the case of papillary thyroid cancer, there is some element of heredity but the genetic basis hasn’t been established.
Intake of dietary iodine is a leading environmental influence of thyroid cancer prevalence in particular. Follicular thyroid cancers tend to be more prevalent in geographic locations with low iodine in diets. In the United States, there is adequate iodine as it is normally added in diets. Diets low in iodine may increase to incidence of papillary thyroid cancer when the victim is also exposed to some radioactivity.
Management of thyroid cancer
Approximately 10% of thyroid cancer cases that occur in the reproductive years of most women tend to be detected during pregnancy or early in their post- partum period (Cooper et al, 2009). In the case of a pregnant woman, treatment and subsequent follow-up tend to be similar to the non pregnant women save for the prescription and use of radioactive iodine. There are certain differences in the manner in which differentiated thyroid cancer and medullary thyroid cancer are treated. However, the most important considerations in the treatment of thyroid cancer in pregnant women must entail:
• Effect of the cancer on the pregnancy
• Effect of the pregnancy on the cancer
• Effects of the management modalities on the outcome of the pregnancy
Managing DTC during pregnancy will mainly fall between two scenarios: The first entails women diagnosed from the beginning during pregnancy while the other one will include women who had previously been infected who have now become pregnant or are anticipating pregnancy. Each of the groups brings with it peculiar therapeutic challenges that demand for a clinical approach guided by the disease stage, preferences of the patient and the particular stage of the pregnancy.
Thyroid surgery at pregnancy
There is no objective consensus on the ideal timing of surgery for DTC women in labor. Generally, individualized decisions tend to be based on the wishes of the patient and other risk factors. However, in the event that a surgery has to be performed as a result of a large tumor or even the patient’s concern then it is better performed during the second trimester of the pregnancy to reduce the risk of abortion that is bound to occur if the surgery is performed in the first trimester. In case there is no life threatening risk, then it is recommended that the surgery be done after delivery (Cooper et al, 2009).
Radioiodine therapy during pregnancy
This therapy is usually contraindicated at pregnancy since it exposes the fetus to highly radioactive elements that may impair its normal development. Therefore, women scheduled for this therapy must exclude their pregnancy phase. Postpartum radioiodine therapy must be deferred for 6-8 weeks after breastfeeding has stopped.
Thyroid hormone replacement and pregnancy
Such a therapy must commence with some pre- pregnancy counseling on the importance of undertaking frequent thyroid stimulating hormone (TSH) and of adjusting dosage.
Admittedly, the numerous incidents of DTC among women and in particular pregnant women have become issues of great concern. Despite the numerous research that has been undertaken on the topic, none has concretely provided the main reason why women continue to be victims of the disease. Nonetheless, if women will be screened early before reaching their prime years, the chances of being treated of the diseases are high and as such the development of the fetus will not be hampered. Additionally, despite the fact that certain risk factors are beyond our control, the ones under human control, such as iodine presence in diets, ought to be addressed and enforced.
There is no doubt whatsoever that the incidents of thyroid cancer are on the rise and especially among women. The data that has been adopted in the research is indeed suggestive despite the fact that it fails to fully convince. It must be admitted that mankind, despite making several advancements in medical technology, has contributed to enhancement of thyroid malignancy by adopting therapeutic radiations as well as nuclear fission. Hence, the resulting high thyroid cancer prevalence has been buoyed by genetic mutation, environmental carcinogens and autoimmune phenomena.
With proper clinical attendance, thyroid cancer can be properly managed with exposing the mother or the fetus to any danger. It is therefore recommended that women should always be screened early in life and regularly to avoid the compromising situations that the find themselves in whenever they are pregnant.
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