So, the full phrase refers to:
A doujinshi (fan comic) released at Comiket 72 by the circle Naruhodou Naruhodo, titled “Tsunade no Inchiryō” (Tsunade’s Medical Treatment), which is an added work (supplement or extra story) for the Naruto franchise.
So, the most logical conclusion: At Comiket 72, a doujinshi titled something like “Naruhodou Naruhodo: Tsunade’s Life Treatment” was released, adding Naruto characters into an Ace Attorney-style setting. So, the full phrase refers to: A doujinshi
Comiket 72 took place on August 17–19, 2007, at Tokyo Big Sight. This was a transitional era for fanworks: digital distribution was rising, but physical doujinshi still reigned supreme. C72 saw a massive presence of Naruto (still at peak popularity post-Time Skip), Ace Attorney (the 2007 Gyakuten Saiban 4 had just been released), and early Touhou projects. The "c72" prefix indicates the work was either sold at that event or digitally circulated shortly after. So, the most logical conclusion: At Comiket 72,