Is radiation therapy contraindicated in the setting of an active abdominopelvic infection?

This question seems deceptively straightforward, but it is anything but straightforward.

There are two major issues here: the first is what does "active infection" mean?

The second is "why is radiotherapy being considered"?

With respect to the infection issue, does the questioner mean an active infection in the abdomen and/or pelvis either caused by or in close proximity to the tumor? The question seems to imply this. However, if the questioner means treating an abdominal pelvic tumor at a time when the patient has an ongoing infection unrelated to the tumor pathophysiologically and/or anatomically, that's a completely different matter.

So, let's break this down a bit.

1. Active infection can mean anything from life-threatening to inconsequ...

Radiation is not contraindicated in the setting of active infection. Often, the presence of active tumor PREVENTS healing of any infection in the proximity of these tumors; and by treating the patient's tumor, healing can be expedited. I am not aware of studies looking at this; but one of my personal experiences was with a patient with long standing hidradenitis and developments of an extensive squamous cell cancer involving the buttocks, anus, and involving the ischial bones with an active osteomyelitis. The patient was being moved to hospice after 2 months of recurring hospitalizations, and we were consulted and delivered hypofractionated radiation therapy alone. The patient fully recovered and was alive 3 years later at my last follow-up...