In the Patnaik grade scheme, what was the MST for Grade II dermal MCTs without adjunctive therapy?

• A. MST not reached
• B. MST = 1,649 days
• C. MST = 119 days
• D. MST = 211 days

Answer: (C)

The question hinges on median survival time for a specific tumor grade and location in the Patnaik system. In Patnaik grading, Grade II dermal mast cell tumors are intermediate in behavior, and when no adjunctive therapy is given, the prognosis is relatively guarded. The historical data show a median survival time of about 119 days for these tumors without additional treatment, meaning half of the dogs are expected to be alive around four months after diagnosis.

This is the best fit because it reflects the typical outcome for Grade II dermal MCTs without extra therapy. The longer figures (about 211 or 1,649 days) would usually reflect cases with some form of adjunct therapy or different tumor contexts, and “not reached” would imply they survived beyond the study duration, which isn’t characteristic of this specific scenario.