Are you a grower or shower?

The adoption of intensity modulated radiation therapy (IMRT) introduced significant variability into the delineation of target volumes across virtually all cancer sites, probably none more than head and neck (H&N). In the old days, targets were based on 2-D x-rays (i.e., bony anatomy). Nowadays people draw elaborate clinical target volumes (CTVs) using CT scans in attempts to reduce toxicity to organs at risk. But there are inevitable tradeoffs with degrees of certainty of tumor coverage. Some people simply use a geometric expansion around gross disease (growers) while others manually draw CTVs based on common anatomic patterns of spread (showers). So far it’s come down to preference, but this month’s study from the DAHANCA group shows that the use of geometric expansions produces much more reproducible target volumes. The ease and uniformity of growers has lead DAHANCA to endorse geometric guidelines to better standardize volumes. We personally respect both growers and showers, and either can achieve more reproducible volumes by using specific target definitions: So check out these Grower Guidelines and Shower Guidelines before your next H&N case.