How would you approach HDR portion of cervical SCC with large area of fistula with sigmoid colon?

Consider using ultrasound every time a tandem is inserted or a Smit sleeve placed under ultrasound guidance (if not already part of routine practice) for tandem guidance, to ensure that a false tract into the fistulous bowel is not produced at the time of tandem placement.

Otherwise, as noted by Dr....

I usually do either hybrid applicator or template based in interstitial. In either situation, would use tandem also.