PO44

Abstract

Purpose Cervical cancer is the most common cancer treated with radiation in Botswana. There is a single linear accelerator and a single HDR brachytherapy unit in the country, treating a median of 200 cervical cancer cases year. About 80% of these are treated with curative intent, using concurrent chemoradiation with brachytherapy boost. Patients in Botswana often present with advanced disease and very bulky tumours. Traditionally, patients who can not have brachytherapy are sent for external beam boost. This not only adds burden onto the very busy single Linac, but also outcomes of patients are compromised. We highlight here seven cases with novel insertions for patients who would have been deemed ineligible for brachytherapy. Materials and Methods We retrospectively revised the records of cervical cancer patients treated with brachytherapy in January 2023, 29 in total. Brachytherapy was delivered in the final week of external beam radiation, or after completion for bulky tumours. The mean age was 46 years and most patients (22, 76%) presented with stage IIB or IIIB, six patients had undergone hysterectomy for stage IB disease. Applicators available were tandem and ovoids, tandem and ring, tandem and cylinder, and cylinder post hysterectomy. Twelve patients (41%) needed interstitial needles. However, seven patients(24%) would previously have been deemed unsuitable for brachytherapy with these applicators due to: 1. Bulky disease with poor response to external beam brachytherapy (three patients). 2. Effaced or destroyed cervix and cavitation at vault post EBRT, traditional tandem and cylinder would not fit (three patients) 3. Stenosis at vault smallest ovoids could not fit and tandem and cylinder would not give adequate dose to bulky tumour (one patient). Results We successfully used three non-conventional methods to complete brachytherapy using available applicators, to treat the 7 patients who would have been deemed ineligible for brachytherapy. Fig. 1. illustrates images from three of the seven patients treated this way. Patient 1: A 55 year old patient with bulky local disease and poor response to EBRT. On day 55, mass still bulky; failed to insert traditional instruments. We inserted tandem and interstitial wires only with no ovoids. Patient 2: A 42 year old patient with stage IIB cancer of the cervix. Cervix had been completely destroyed post external beam radiation, which then created a small cavity at the vault. No gross residual disease. An intrauterine tandem was inserted, then a small (2cm) cylinder was placed into the vault cavity, followed by three 3.5cm cylinders. Patient 3: A 60 year old patient with Stage IIIB cancer of the cervix with bulk of tumour on the left.The smallest ovoids could not fit at the vault, yet tandem and cylinder would not give enough dose coverage especially to the left. A tandem and left ovoid only were inserted, with interstitial wires on the left. All three patients managed to complete radical chemo radiation with brachytherapy, with HRCTV D90 EQD2 >85Gy for all three and dose to OARs within normal. Conclusion We found innovative ways of delivering brachytherapy to these patients, outside conventional applicator insertions, whilst maintaining the general treatment principles. Patients were able to receive adequate doses to HRCTV with sparing of normal organs. Further studies are needed to evaluate toxicity and survival in these patients. Cervical cancer is the most common cancer treated with radiation in Botswana. There is a single linear accelerator and a single HDR brachytherapy unit in the country, treating a median of 200 cervical cancer cases year. About 80% of these are treated with curative intent, using concurrent chemoradiation with brachytherapy boost. Patients in Botswana often present with advanced disease and very bulky tumours. Traditionally, patients who can not have brachytherapy are sent for external beam boost. This not only adds burden onto the very busy single Linac, but also outcomes of patients are compromised. We highlight here seven cases with novel insertions for patients who would have been deemed ineligible for brachytherapy. We retrospectively revised the records of cervical cancer patients treated with brachytherapy in January 2023, 29 in total. Brachytherapy was delivered in the final week of external beam radiation, or after completion for bulky tumours. The mean age was 46 years and most patients (22, 76%) presented with stage IIB or IIIB, six patients had undergone hysterectomy for stage IB disease. Applicators available were tandem and ovoids, tandem and ring, tandem and cylinder, and cylinder post hysterectomy. Twelve patients (41%) needed interstitial needles. However, seven patients(24%) would previously have been deemed unsuitable for brachytherapy with these applicators due to: 1. Bulky disease with poor response to external beam brachytherapy (three patients). 2. Effaced or destroyed cervix and cavitation at vault post EBRT, traditional tandem and cylinder would not fit (three patients) 3. Stenosis at vault smallest ovoids could not fit and tandem and cylinder would not give adequate dose to bulky tumour (one patient). We successfully used three non-conventional methods to complete brachytherapy using available applicators, to treat the 7 patients who would have been deemed ineligible for brachytherapy. Fig. 1. illustrates images from three of the seven patients treated this way. Patient 1: A 55 year old patient with bulky local disease and poor response to EBRT. On day 55, mass still bulky; failed to insert traditional instruments. We inserted tandem and interstitial wires only with no ovoids. Patient 2: A 42 year old patient with stage IIB cancer of the cervix. Cervix had been completely destroyed post external beam radiation, which then created a small cavity at the vault. No gross residual disease. An intrauterine tandem was inserted, then a small (2cm) cylinder was placed into the vault cavity, followed by three 3.5cm cylinders. Patient 3: A 60 year old patient with Stage IIIB cancer of the cervix with bulk of tumour on the left.The smallest ovoids could not fit at the vault, yet tandem and cylinder would not give enough dose coverage especially to the left. A tandem and left ovoid only were inserted, with interstitial wires on the left. All three patients managed to complete radical chemo radiation with brachytherapy, with HRCTV D90 EQD2 >85Gy for all three and dose to OARs within normal. We found innovative ways of delivering brachytherapy to these patients, outside conventional applicator insertions, whilst maintaining the general treatment principles. Patients were able to receive adequate doses to HRCTV with sparing of normal organs. Further studies are needed to evaluate toxicity and survival in these patients.