Random Directed Biopsies: Location of Tumour
Two studies dispute the utility of random biopsies. Tanzler et al5 included 156 patients who underwent deep tissue biopsies, and found the pickup rate to be 0% from the nasopharynx and piriform sinus (Table 1). A systematic review and meta-analysis of 673 patients recommends against random biopsies given pickup rates of often 0% in the literature8.
Several studies have specifically reported on pickup rates from the practice of random directed biopsy9,5,10,11 (table 1.1). Other authors have and have detailed the positive sites by location from their general workup including, but no limited to, random biopsies1,12,13,14,15,16,17(table 1.2).
These studies call into question the utility of random biopsies, especially for two commonly targeted sub-sites, the nasopharynx and hypopharynx. In the nasopharynx the pickup rate ranged from 0-9.4%5,11,9. The highest pickup rate reported by Haas et al9 is a retrospective study published in 2002, using data from a time before modern imaging was routinely utilised for workup preceding a biopsy. Similarly low pickup rates were observed in the piriform fossa alone, ranging from 0-4.2%9,5,11,14. When the entire hypopharynx is considered, a higher pick up rate is evident, ranging from 1.7% to 6%15,13 (table 1.2, note that pickup rate here is of total number of CUP patients).
The studies demonstrate significant heterogeneity in their workup, as several include directed biopsies from sites considered suspicious on imaging, calling into question the nature of the biopsies as ‘true random biopsies’. No studies have specifically performed biopsies following negative imaging and shown to be positive for cancer. Given the generally low pick up rates, in the era of cross-sectional imaging and PET-CT, the practice of random directed biopsies cannot be recommended.