Jan Groenewegen
Department of Radiation Oncology, Royal Adelaide Hospital
Fellow Radiation Oncology-Brachytherapy

Ivan Iankov
Statistician
Department of Radiation Oncology, Royal Adelaide Hospital

Scott Carruthers
Radiation Oncologist
Department of Radiation Oncology, Royal Adelaide Hospital

Raghavendra Gowda
Radiation Oncologist
Department of Radiation Oncology, Royal Adelaide Hospital

Braden Higgs
Radiation Oncologist
Department of Radiation Oncology, Royal Adelaide Hospital

Scott Penfold
Medical Physicist
Department of Medical Physics, Royal Adelaide Hospital, South Australia, Department of Physics, University of Adelaide, South Australia

Wendy Phillips
Medical Physicist
Department of Medical Physics, Royal Adelaide Hospital, South Australia, Department of Physics, University of Adelaide, South Australia

Paul Reich
Medical Physicist
Department of Medical Physics, Royal Adelaide Hospital, South Australia

Background and purpose

The standard of care for the treatment of locally advanced cervical cancer consists of concurrent chemo radiotherapy using external beam radiation therapy with weekly cisplatin followed by HDR brachytherapy [1]. Modern approaches to brachytherapy include 3D treatment planning using either CT or MRI, as described by the recommendations from the GEC-ESTRO Working Group [2]. Three-dimensional treatment planning allows for dose-volume evaluation of the target as well as organs at risk.

Since June 2013, cervical cancer patients at the Royal Adelaide Hospital have been treated using 3D planned HDR brachytherapy, IMRT and chemotherapy. Brachytherapy treatment planning was performed according to the GEC-ESTRO recommendations [2]. We report the dosimetric analysis of the HDR-brachytherapy and the outcomes of this treatment.

Methods

Since the start of this treatment we have prospectively collected patient details, treatment details and follow-up data in an in-house database. We performed a dosimetric analysis to investigate the effect of patient and treatment factors on CTV HR D90%. We also obtained failure-free survivals (FFS) by considering events of local and distant failures and deaths. Following this we performed competing risks analysis to determine cumulative incidence for local failure. Results were compared with those published elsewhere in the literature.

Results

Between 2013 and 2018 we treated 84 patients with radical (chemo)radiotherapy to the cervix. The median CTV HR D90% achieved is 112%. As expected, interstitial needles were more frequently used in cases with large tumours (p<0.05) and the utilisation of needles might contribute to achieve CTV HR D90% above 100%, especially in cases where organs at risk were limiting the dose.

Our preliminary survival analyses are based on follow-up records for 65 patients with 15 lost-to-follow-ups, hence results will be updated soon when follow-up data collection is completed. The median follow-up is 27.4 months. The medium FFS is 43.2 months, 1-year and 2-year FFS rates are 72.5% and 55.7% respectively. FIGO stage appears to have impact on FFS (p 0.075). One and two-year cumulative incidence rate of local failure are 13% and 20.7% respectively.

Conclusions

Our preliminary data shows that our results are comparable with the published literature. Interstitial needles were used more often in larger tumours. The use of needles helped to achieve a better D90 and spare the OAR in these tumours.

References

[1]. Morris M et al.; NEJM 1999

[2]. Haie-Meder C et al.; Radiother Oncol 2005


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