PO21

Abstract

Brachytherapy (BT) has been utilized for the treatment of anal cancer for many decades. A previous systematic review had shown benefit of BT boost in patients undergoing curative intent chemo-radiotherapy for anal canal cancer. Despite this, the use of BT boost is still restricted to a few chosen institutions and is typically not mentioned as a therapeutic alternative in the well-known international standards. Barriers to its widespread implementation have been identified as specialised knowledge, complexity, and equipment. There is also not much evidence in literature regarding the use of BT as a sole modality for treating early stage anal cancers. Christchurch Oncology has 12 years’ of clinical experience with High Dose rate intracavitary/ interstitial brachytherapy for Gynaecological and Prostate cancers, however this is our first experience of treating anal cancer with brachytherapy. We present a case study of a patient with localised primary anal cancer that was referred to our department to determine if brachytherapy would be an option. This 80yr old fit/independent female had adjuvant pelvic radiation treatment for a cervical cancer (Stage 1B) SCC in 1981 receiving a dose of 45Gy/20#. She was recently diagnosed with SCC of Anal Canal (cT1 N0) and further curative external beam radiation was deemed too high risk in terms of toxicities and morbidities and patient was reluctant to accept abdominoperineal resection for reasons relating to quality of life when dealing with a permanent stoma. Even though there is not much evidence for using brachytherapy as a sole modality for curative treatment for anal cancer, given the limited treatment options available, this would not be an unreasonable approach. Staging Colonoscopy, FDG PET CT scan, and MRI highlighted a superficial tumour that extended a total of 16mm from proximal anal canal to mid anal canal from 12-7 o'clock position without invasion or lymphadenopathy. A pre-BT MRI was performed with the Nucletron Multichannel applicator (MCA) in situ. The plan was optimised in Oncentra Brachy (OCB) V4.6.2 using a combination of central channel and superficial channels. A prescription dose of 33Gy/6# was chosen and the final dose coverage of the targets are listed below: Dose reporting for targets: Dose per fraction / Dose per treatment EQD2Gy (a/b =10) HRCTV: D90= 5.8Gy/ 45.4Gy D100= 5.3Gy / 41.0Gy IRCTV: D90= 4.8Gy / 35.6Gy D100= 4.2Gy / 29.9Gy Following completion of BT, patient developed radiation dermatitis with some soreness around the perianal area that was treated with local suppositories and hydrocortisone cream. At 3 and 6 months follow-up, there was no signs of active dermatitis or any bowel incontinence Brachytherapy (BT) has been utilized for the treatment of anal cancer for many decades. A previous systematic review had shown benefit of BT boost in patients undergoing curative intent chemo-radiotherapy for anal canal cancer. Despite this, the use of BT boost is still restricted to a few chosen institutions and is typically not mentioned as a therapeutic alternative in the well-known international standards. Barriers to its widespread implementation have been identified as specialised knowledge, complexity, and equipment. There is also not much evidence in literature regarding the use of BT as a sole modality for treating early stage anal cancers. Christchurch Oncology has 12 years’ of clinical experience with High Dose rate intracavitary/ interstitial brachytherapy for Gynaecological and Prostate cancers, however this is our first experience of treating anal cancer with brachytherapy. We present a case study of a patient with localised primary anal cancer that was referred to our department to determine if brachytherapy would be an option. This 80yr old fit/independent female had adjuvant pelvic radiation treatment for a cervical cancer (Stage 1B) SCC in 1981 receiving a dose of 45Gy/20#. She was recently diagnosed with SCC of Anal Canal (cT1 N0) and further curative external beam radiation was deemed too high risk in terms of toxicities and morbidities and patient was reluctant to accept abdominoperineal resection for reasons relating to quality of life when dealing with a permanent stoma. Even though there is not much evidence for using brachytherapy as a sole modality for curative treatment for anal cancer, given the limited treatment options available, this would not be an unreasonable approach. Staging Colonoscopy, FDG PET CT scan, and MRI highlighted a superficial tumour that extended a total of 16mm from proximal anal canal to mid anal canal from 12-7 o'clock position without invasion or lymphadenopathy. A pre-BT MRI was performed with the Nucletron Multichannel applicator (MCA) in situ. The plan was optimised in Oncentra Brachy (OCB) V4.6.2 using a combination of central channel and superficial channels. A prescription dose of 33Gy/6# was chosen and the final dose coverage of the targets are listed below: Dose reporting for targets: Dose per fraction / Dose per treatment EQD2Gy (a/b =10) HRCTV: D90= 5.8Gy/ 45.4Gy D100= 5.3Gy / 41.0Gy IRCTV: D90= 4.8Gy / 35.6Gy D100= 4.2Gy / 29.9Gy Following completion of BT, patient developed radiation dermatitis with some soreness around the perianal area that was treated with local suppositories and hydrocortisone cream. At 3 and 6 months follow-up, there was no signs of active dermatitis or any bowel incontinence