Abbreviated CT protocol for postoperative surveillance of renal cancer

Postoperative surveillance protocols after nephrectomy for kidney cancer include periodic computed tomography (CT) scans of the chest and abdomen. A single study exposes the patient to 21 mSv (equivalent to 7-year exposure to natural background radiation). The objective of this study was to evaluate the hypothesis that an abbreviated CT protocol restricted to the chest and upper abdomen (i.e., to the level of the intervertebral disk L3-L4) is sufficient for routine postnephrectomy follow-up as it detects most tumor recurrence with lower radiation exposure.

We identified 493 patients treated with radical or partial nephrectomy for localized kidney cancer and followed with periodic CT scans of the chest and abdomen for prolonged periods. The frequency and location of cancer recurrence were documented. The ratio of infield recurrence for the complete chest, and abdomen and for the abbreviated protocol was recorded. The decrease in radiation exposure was calculated.

At a median follow up of 96 months, 82 patients (16.6%) developed recurrence. The frequent sites of recurrence were the lungs (53), the bones (9), and local recurrence (22). Complete chest and abdominal CT identified 78 of the recurrences (95%) and the abbreviated protocol identifying all but one of these (94%). The abbreviated protocol exposed the patient to 48% (standard deviation 4.3%) less radiation compared to the full protocol.

Using an abbreviated CT protocol that includes the chest and upper abdomen for surveillance after surgery of localized kidney cancer decreases radiation exposure by half with only a minor decrease in the sensitivity of the examination.