Does an erroneous diagnosis of squamous-cell carcinoma of the anal canal and anal margin at first physician visit influence prognosis?

Patients with squamous-cell carcinoma of the anal canal (n=125) and its margin (n=76) were divided into five groups: those with an erroneous diagnosis and a correct diagnosis made at first physician visit; those with a history of less than six months, between six and 18 months, and more than 18 months. Patients with canal tumors had an erroneous diagnosis made more frequently than patients with margin tumors. In both groups patients with an erroneous diagnosis had longer histories than patients with a correct diagnosis. Among patients with erroneously diagnosed canal tumor, pain, the feeling of a lump, anal discharge, and pruritus ani occurred less frequently than among correctly diagnosed patients. The prognosis was worse among patients with erroneously diagnosed canal tumors compared with correctly diagnosed patients. Such a difference could not be found among patients with margin tumors. There was a gradual worsening of the prognosis among patients with increasing length of history and canal tumors, in contrast to patients with margin tumors, in whom only a history of more than 18 months was associated with a worse prognosis.