An ablation system comprising: an ablation device including: a handle assembly including a housing configured for operable engagement by a user; and an electrode assembly including a tubular electrode having an open proximal end and a closed distal end, wherein the tubular electrode is movable relative to the housing to adjust an insertable length of the electrode assembly to adjust ablation length; and a locking mechanism for selectively securing the tubular electrode relative to the housing, the locking mechanism comprising a plurality of radially spaced tapered flanges formed on a distal end of the housing, the plurality of radially spaced tapered flanges collectively defining a longitudinal bore therethrough and include an external thread formed thereabout, said longitudinal bore being sized to selectively receive the electrode therethrough when the plurality of radially spaced tapered flanges are spaced relative to each other, wherein said external thread is configured to engage an internal thread of a locking nut such that when the locking nut is threaded onto the external thread of the flanges, the flanges are forced radially inward until internal surfaces of the flanges engage the electrode assembly. an ablation device including: a handle assembly including a housing configured for operable engagement by a user; and an electrode assembly including a tubular electrode having an open proximal end and a closed distal end, wherein the tubular electrode is movable relative to the housing to adjust an insertable length of the electrode assembly to adjust ablation length; and a locking mechanism for selectively securing the tubular electrode relative to the housing, the locking mechanism comprising a plurality of radially spaced tapered flanges formed on a distal end of the housing, the plurality of radially spaced tapered flanges collectively defining a longitudinal bore therethrough and include an external thread formed thereabout, said longitudinal bore being sized to selectively receive the electrode therethrough when the plurality of radially spaced tapered flanges are spaced relative to each other, wherein said external thread is configured to engage an internal thread of a locking nut such that when the locking nut is threaded onto the external thread of the flanges, the flanges are forced radially inward until internal surfaces of the flanges engage the electrode assembly. a handle assembly including a housing configured for operable engagement by a user; and an electrode assembly including a tubular electrode having an open proximal end and a closed distal end, wherein the tubular electrode is movable relative to the housing to adjust an insertable length of the electrode assembly to adjust ablation length; and a locking mechanism for selectively securing the tubular electrode relative to the housing, the locking mechanism comprising a plurality of radially spaced tapered flanges formed on a distal end of the housing, the plurality of radially spaced tapered flanges collectively defining a longitudinal bore therethrough and include an external thread formed thereabout, said longitudinal bore being sized to selectively receive the electrode therethrough when the plurality of radially spaced tapered flanges are spaced relative to each other, wherein said external thread is configured to engage an internal thread of a locking nut such that when the locking nut is threaded onto the external thread of the flanges, the flanges are forced radially inward until internal surfaces of the flanges engage the electrode assembly.