Brachytherapy In Treating Cervical Cancer: Advancements And Techniques

Discuss about the Brachytherapy in Treating Cervical Cancer.

Brachytherapy is a form of cancer treatment where radioactive compounds sealed in a wire, pellet or capsule is introduced into the body with the help of a catheter in order to damage the DNA of the cancer cells. It has a wide spread of application in the treatment of prostate cancer and cervical cancer. The benefits of brachytherapy are that it allows an augmented dose of radiation in a limited area unlike the other types of the radiation treatments. It actually helps to lessen the damage to the surrounding tissues due to radiation. The last two papers are about improving the image guided brachytherapy techniques in the treatment of cervical cancers. Two of my chosen papers are related to the same, as IGBT helps in a more accurate treatment and lesions that are too large for applying the other treatment techniques.  Significant improvements have occurred in the last three decades due to the use of the 3-D image guided procedures. Incorporation of the transrectal US in the image guided brachytherapy have been found to be effective in centers that have do not access to MRI. The commonly used method in the treatment of the cervical cancer is the Manchester Point A system. But the 2-D X ray image shows no contract of the soft tissues. Image guided brachytherapy helps to target the desired tissue.  There had been increasing evidence of the benefits of the image guided brachytherapy in cervical cancer, which is the main rationale behind the chosen papers.

The objective of this paper is to give an overview of the gynecologic brachytherapy, with a focus on the recent advancements and their implications on the cervical cancer in women. The paper describes about the evaluation and the staging of the patient, According to this paper the initial stages of evaluation includes the cervical biopsy of the hystopathological diagnosis. According to the FIGO recommendations, patients with who would be receiving the radiation treatment should have a planning of the CT stimulation before the initiation of the EBRT.

The paper also brings about a comparison between the high dose rate brachytherapy and low dose rate brachytherapy. Previously LDR was used exclusively for treating the cancer by using a cesium -137 isotope. Since 2000s, the utilization of the HDR has increased considerably. The HDR employs a remote after loading technology allowing a small iridium source connected to the end of a cable that is robotically driven via the multiple channels ceasing at the dwell positions for different span of time.  The article also refers to a third type of treatment that is commonly not used in the US known as the pulse dose rate (PDR) brachtherapy. The paper also gives an account of the choices, by which cervical brachytherapy can be performed, namely the intracavitary, interstitial, or a combinatory approach. A cohort study was done in order to measure the clinical outcomes of the image guided brachytherapy. The study compared the 2D versus the 3D IGBT . In the patients treated with both the EBRT plus chemotherapy followed by a brachytherapy could show a local relapse free survival 74 % of the selected patients. Similar improvement was found in another study containing patients from Vienna.

Impression

It can be understood from the paper that brachytherapy can improve the local control, reduce the toxicity and improve the overall survival rate of cervical cancer in women. The study of the paper also enables one to understand that the disadvantage of brachytherapy is that, it is invasive. The randomized control study involving 2D planning and 3D planning in selected patients showed better results in patients being treated with image guided brachtherapy. The paper also gave an account of the appropriate treatment target volume, the appropriate dose and the fractionation scheme.

Although the progression from the 2D- 3D based imaging and the treatment planning for the cervical cancer has increased the overall survival of the women. Further data from the 3-D based treatment is required associated with the decrease in the toxicity of the technique.

The previous paper focused on the effectiveness of overall brachytherapy in cervical cancer, but this article will aim to focus on the advantages of using imaging brachytherapy over conventional methods of brachytherapy.  The paper involves a retrospective analysis of the outcomes in patient suffering from stage IB-IVA cervical cancer treated with primary radiation therapy. The outcome measures were the relapse free survival of the patient, distant metastasis, pelvic control and other adverse events related to the treatment. 126 patients have been analyzed out of which 43 patients have been treated with CBT between the years 2000-2007, and 83 patients have been treated with IGBT between the years 2007- 2012. The conventional bracgytherapy involved the application of the low dose brachytherapy and high dose rate brachytherapy was used after 2005. The standard brachytherapy applicators used were intracavatary ovoids and tandem.  From 2011, interstitial needles can be introduced in to the ovoids for optimizing the dose distribution around the neoplasia. All the records of the adverse events were recorded if prompted by the signs and the symptoms.  The results concluded that cervical cancer survival rates have increased with the introduction of IGBT.

The application of the MRI based adaptive IGBT technique was found to be useful for the patients with stage IB-IVA cervical cancer. The overall survival rate was found to improve from 51% to 83% with the shift from conventional brachytherapy to imaging brachytherapy. The study confirmed that there had been a significant decrease in the distant metastasis in the group treated with IGBT. The pelvic control rates were also found to be improved in the IGBT group. Data obtained from the patient’s record found that the IGBT patients were more likely to complete the chemotherapy faster than the patients’ receiving the conventional brachytherapy.

Application to Practice

Application to practice

The use of IGBT in the primary chemo radiation of the cervical cancer is superior to the CBT and should be considered as the new standard of care. It can be known from the paper that there is a requirement of improvement of the nodal and the PAN tumor control, using the PET-CT and the lessening of the adverse events in both the standard and the adaptive IMRT. A 3D MRI based image guided brachytherapy have been found to reduce the toxicity as discussed in the previous paper. The objectives of the paper were realistic. One of the limitations of the paper is that the sample population of the cohort was not large. Although there are several studies that have actually provided the evidences of imaging brachytherapy.

Brachytherapy is an essential component for the treatment of the cervical cancers that have progressed locally. It allows the dose of the tumor to be amplified sparing the nearby tissues. Image guided brachytherapy have found to lessen the local recurrence. The article focuses on how the 3D conformal brachytherapy can be used in a hospital setting and how the brachytherapy services can be improved. The radiological studies operative parameters and patient workflow and intensive therapy planning can pose challenge to the clinical resources. The paper also discuses about the translational research opportunities in the field of brachytherapy. One of the concerns is that some proportion of the tumor will display biological resistance to the radiations and even to brachytherapy.

The objective of the paper was to find new advancement in the field of imaging-brachytherapy. Hence the paper had been appropriate in stating the recent advancements in the radiotherapy techniques like the intensity modulated radiotherapy (IMRT) and the stereotactic body radiotherapy (SBRT). This research paper also enables one to understand the demerits of the therapy, such as IMRT had been unsuccessful in achieving the target volume doses unlike that of the image guided brachytherapy.

The paper informs that IGBT is more time consuming and requires individual planning and contouring. Additional resources such as MRI/CT scans and the compatible applicators are required. The cost of setting up an IGBT is about 10-15 % more than that of the conventional procedures of brachytherapy. In a clinical setting with IGBT facilities there should be provisions for an intrauterine brachytherapy applicator as most of the patients will be having an intact uterus, which will require the placement of an intrauterine tube.

Conclusion

It can be understood from all the three papers that image guided brachytherapy makes 3D models by using the cross sectional image. It should be mentioned that the points of similarities between the three papers were much more than the differences as all the three papers focused on the advancements in the field of brachytherapy in treating cervical cancers and the advantage of using image dependant brachytherapy over the conventional treatment of the brachytherapy. The difference between the three papers is that the last two papers focused more on the improvements in the image guided brachytherapy. The last papers exclusively mentioned the advancements rather than just comparing with the conventional standards.

Various retrospective studies and the cohort studies described in the three papers have showed better survival rates in patients with cervical cancer. Among the three papers my choice of paper was the first one as it had elaborately stated the difference between the new techniques and the old ones such as the difference between the HDR brachytherapy and the LDR brachytherapy, the selection of the applicator. It further gives information about the intracavity brachytherapy, interstitial brachytherapy. An appropriate treatment planning was mentioned. This assignment has not only aided us to know about the different image guided brachytherapy techniques but have also informed us with the procedures undertaken in brachytherapy

References

Banerjee, R., & Kamrava, M. (2014). Brachytherapy in the treatment of cervical cancer: a review. International journal of women's health, 6, 555.

 Otter, S., Franklin, A., Ajaz, M., & Stewart, A. (2016). Improving the efficiency of image guided brachytherapy in cervical cancer. Journal of Contemporary Brachytherapy, 8(6), 557–565. https://doi.org/10.5114/jcb.2016.64452

Rijkmans, E. C., Nout, R. A., Rutten, I. H. H. M., Ketelaars, M., Neelis, K. J., Laman, M. S., ... & Creutzberg, C. L. (2014). Improved survival of patients with cervical cancer treated with image-guided brachytherapy compared with conventional brachytherapy. Gynecologic oncology, 135(2), 231-238