Subclinical disease revisited

It has become commonplace to treat postoperative patients with adjuvant radiotherapy to increase local control. The reduction in local recurrences seen in patients with head and neck cancer following radiotherapy led to coining of the term "subclinical disease" to describe the presumed presence of small, clinically undetectable, nests of tumor cells which remain even after the most aggressive of surgeries. The basic assumption fundamental to the concept of subclinical disease is that any patient with residual disease will suffer a local failure if left untreated. For example, lymph node involvement, either clinically evident or pathologically proven, is considered an absolute indication for adjuvant therapy. A positive or "close" or "microscopically positive" margin is also considered grounds for further treatment. The purpose of this communication is to critically discuss recent reports that challenge this assumption.