An intracavitary applicator for a medical procedure, comprising: an elongate hollow outer shell having a given length and an outer diameter, an open proximal end, and a closed and curved distal end, the outer shell having a first wall thickness (T 1) on a side and a second wall thickness (T 2) at the distal end, the second wall thickness (T 2) being smaller than the first wall thickness (Ti); an elongate insert selectively coupled to the outer shell from the open proximal end of the outer shell, the elongate insert having a given length, an open proximal end, a curved distal end, an elongate central through-bore extending substantially the whole length of the elongate insert with one end terminating at the distal end, and at least one outer guide channel formed on an outer surface of the elongate insert, the at least one outer guide channel extending from the proximal end to the distal end of the elongate insert, the at least one outer guide channel and an inner wall of the outer shell defining at least one enclosed pathway; and an endcap selectively coupled to the proximal end of the elongate insert to close the proximal ends of the elongate insert and the outer shell when assembled, the endcap having an axially extending endcap through-bore and at least one angularly spaced guide hole, the endcap through-bore and the at least one guide hole communicating and aligned with the central through-bore and the at least one outer guide channel of the elongate insert, respectively, to facilitate selective positioning of at least one instrument or therapeutic agent for the medical procedure from outside the endcap towards the distal end of the elongate insert, wherein the smaller second wall thickness (T 2) facilitates closer placement of the at least one instrument or therapeutic agent carried within the at least one outer guide channel or the central through-bore to a target area for the medical procedure. an elongate hollow outer shell having a given length and an outer diameter, an open proximal end, and a closed and curved distal end, the outer shell having a first wall thickness (T 1) on a side and a second wall thickness (T 2) at the distal end, the second wall thickness (T 2) being smaller than the first wall thickness (Ti); an elongate insert selectively coupled to the outer shell from the open proximal end of the outer shell, the elongate insert having a given length, an open proximal end, a curved distal end, an elongate central through-bore extending substantially the whole length of the elongate insert with one end terminating at the distal end, and at least one outer guide channel formed on an outer surface of the elongate insert, the at least one outer guide channel extending from the proximal end to the distal end of the elongate insert, the at least one outer guide channel and an inner wall of the outer shell defining at least one enclosed pathway; and an endcap selectively coupled to the proximal end of the elongate insert to close the proximal ends of the elongate insert and the outer shell when assembled, the endcap having an axially extending endcap through-bore and at least one angularly spaced guide hole, the endcap through-bore and the at least one guide hole communicating and aligned with the central through-bore and the at least one outer guide channel of the elongate insert, respectively, to facilitate selective positioning of at least one instrument or therapeutic agent for the medical procedure from outside the endcap towards the distal end of the elongate insert, wherein the smaller second wall thickness (T 2) facilitates closer placement of the at least one instrument or therapeutic agent carried within the at least one outer guide channel or the central through-bore to a target area for the medical procedure.