How do you manage parathyroid carcinomas with positive microscopic margins?

As parathyroid ca is rare and no reliable data about post-op RT exist, we have to extrapolate from common tumors about which we have data. If this was a sq.c.ca in the low neck, or thyroid ca, we would treat the primary site (positive margins) to 66-70 Gy and neck levels II-IV as well as VI and uppe...