High Dose Rate Brachytherapy Boost with Newly Made Surface Applicator in Anal Canal Cancers: Our Experience

Abstract

Purpose/Objective(s): Conservative treatment of cancer of anal canal is a better alternative to radical surgery. We have made a simplesurface applicatorforthe treatmentofcarcinomaof analcanal. Ouraimwasto evaluate therole ofthis newlymadesurface applicator for intraluminal brachytherapy following chemoradiotherapy in carcinoma of anal canal patients. Materials/Methods: In our study, we included 20 patients with squamous cell carcinoma of anal canal treated with combined chemoradiotherapy.AllpatientsweregivenMitomycinC+5FluorouracilonDay1to5,followedbyexternalbeamradiotherapyfrom Day 6. The dose of external beam radiotherapy was 50 Gy in 25 #. Chemotherapy was repeated every 28 days for 2 more cycles. In ourstudy,wehavedonebrachytherapywithsurfaceapplicatordesignedbyus.Theapplicatorwasfabricatedfromaclearcastacrylic cylindricalrodof10cmslengthand2/2.5cmindiameter.Itscentralportionwasdrilledandametallicrodwasfixedinitbyascrew mechanism to act as a handle. Five grooves were drilled on the surface of the applicator along its length in such a manner that the distance between each parallel groove was 1 cm. The grooves were wide enough for steel needles of 6 F diameter provided for interstitialbrachytherapyonmicroSelectronHDRofNucletron.Theneedleswereinsertedthroughthelowerendandupperendswere blind. The brachytherapy was given 7-10 days after external radiotherapy. Total of 15 Gy were given in 2 # at 1 week intervals, on microSelectron HDR with Iridium 192. The brachytherapy was given selectively to the involved wall of anal canal. Results: The treatment was well tolerated. We didn’t face any problems in insertion of the applicator. Follow-up of these patients ranged from 6 to 40 months. The 2-year locoregional control (LRC), disease free survival (DFS). and overall survival (OS) were 80%, 85%. and 90%, respectively. None of the patients developed any serious complications. Only 2 patients developed bleeding per rectum and were managed conservatively. Conclusions: Brachytherapy with the newly designed surface applicator is simple and inexpensive. With this new applicator we can selectively treat the wall of anal canal having the disease and sparing the rest of the normal wall. It is a good alternative to interstitial brachytherapy in superficial cancers of anal canal. Author Disclosure: R.K. Vyas, None; K.R. Jani, None; S. Unnikrishnan, None; D.C. Bhavsar, None; A. Kumar, None.