Genetic Analysis and Retinoblastoma - Research Paper Example

Chemoreduction is used as the initial management of retinoblastoma. The most commonly used therapeutic agents are carboplatin, etoposide, and vincristine (Shields, 2004). When an adequate tumor reduction is achieved, focal therapy is used on individual tumors. Such focal therapies are; laser photocoagulation, thermotherapy, plaque radiotherapy, and cryotherapy. Plaque radiotherapy is used for tumors that fail other therapies and which reach a size of 8 or 10 mm. On the other hand, laser photocoagulation is used for small retinoblastoma located posterior to the eye equator. In thermotherapy, tumors are heated using a diode infrared laser system and are usually carried out together with carboplatin or chemo reduction so as to enhance their effectiveness. For those tumors, which are adjacent to the fovea and optic nerve, thermotherapy is best suited (Shields, 2004).

Cryotherapy is very useful in the treatment of equatorial and peripheral tumors and it allows tumor consolidation after chemo reduction. In plaque radiotherapy, a radioactive implant is placed on the sclera over the base of retinoblastoma so as to irradiate the tumor. This therapy is used for those tumors, which are less than 16mm in base and 8 mm in thickness (Shields, 2004).

In external beam radiotherapy, the whole eye is irradiated to treat advanced retinoblastoma especially if there is diffuse vitreous seeding. However, this radiation can increase the risk of developing a second tumor (Roarty, Mclean, and Zimmerman, 1988). Enucleation is most appropriate if there is no hope for useful vision or if there is the possibility of the tumor metastasizing to affect the optic nerve, choroid, and orbit. Through this method, the eye can be removed when intact and at the same time ensuring no seeding of the malignancy into the orbit (Shields, 2004; Murali, Patricia, Everlyn, Sharon, and Richard, 2007).

Genetic testing can be done during pregnancy to determine whether a child is likely to develop retinoblastoma. This test is done only if the genetic change responsible for retinoblastoma in the family has been identified. This testing allows the embryo to be tested just before implantation in the womb is done (Harbour, 1998). Though this technique is new, it has been performed many times and it has a low rate of achieving a pregnancy. There are numerous advantages of genetic testing as it reduces family uncertainties about the future, it enhances more accurate genetic counseling and the child’s attitude towards reproduction in adult age is made more responsible. However, genetic testing violates the rights of children, as they are not involved in decision-making affecting their lives. Reproductive plans can also be altered. Predictive genetic testing can also lead to emotional harm and unwarranted anxiety about possible early signs before the presentation of any disorder and consequently damaging a child’s sense of self-esteem (Marteau,1994)

Given that some forms of retinoblastoma are hereditary, research in retinoblastoma will help the ineffective management of the condition by providing insights into the problem. The information on retinoblastoma will also be important in enhancing effective counseling in regard to the risk of retinoblastoma in families that have a history of this disease. With the availability of genetic tools such as PCR, this research is also justified from the feasibility point of view. This research hopes to understand the impact of retinoblastoma genetic testing on family planning.

Hypothesis

Null hypothesis
- Those who are at risk of retinoblastoma are more or equally likely to plan to have children than those who are not at risk

Alternative hypothesis
- Those who are at risk of retinoblastoma are less likely to plan to have children than those who are not at risk

Variables
Independent variables. Have retinoblastoma (Yes/No)
Dependent variables. Plan to have children (Yes/No)

Methodology
Sampling plan
Those with retinoblastoma or at risk will be enrolled from medical records of already known cases to reduce the cost of carrying out genetic testing. A negative control will be included for comparison purposes. The negative control will include those people who are not at risk of developing retinoblastoma. Only adults will be included in the two groups.

Ethical considerations
Consent will be obtained from the respondents in writing to ensure the confidentiality of the information they give.

Data collection
Data will be collected through the administering of questionnaires and also through interviews. The questionnaire will have two questions. The first question will seek to provide information on whether the respondent has retinoblastoma or not while the second one, will answer whether retinoblastoma can change their plan to have children.

Statistical analysis
The data to be collected will have one dependent and one independent variable. Both variables are nominal as they belong to a definable category. Bivariable analysis of a nominal dependent variable will be used. McNemar’s Test for chi-square distribution will be used to determine if there is a significant difference between the proportions.

Reporting of results
The results from these findings can be shared through conferences, annual meetings, journals and professional newsletters.