Table 5.

Proposed HPP surveillance regimen

TumorRecommended surveillanceAge to beginInterval
PGL/PHEOBlood pressure at all medical visitsa6–8 yearsAnnual (at minimum)
Plasma methoxytyramine6–8 yearsAnnual
PFMb,c,d,e or 24-h urine fractionated metanephrinesf6–8 yearsAnnual
Optional: serum chromogranin A6–8 yearsAnnual
Whole-body MRI (skull base to pelvis)g6–8 yearsBiennial
Optional: neck MRI ± contrasth6–8 yearsBiennial
GISTComplete blood count (w/RBC indices)6–8 yearsAnnual
  • Abbreviations: PFM, plasma-free metanephrines; RBC, red blood cell.

  • aBlood pressure in children should be assessed using age- and height-specific normative ranges (https://www.nhlbi.nih.gov/files/docs/guidelines/child_tbl.pdf; ref. 27).

  • bReference to pediatric reference intervals for plasma (71, 72) and urine (73) metanephrines should be considered.

  • cIdeally, to limit false positive results, PFMs should be collected from an indwelling venous catheter after patient has been lying supine for ≥30 minutes. Clinicans may elect to bypass this approach, but marginally elevated results should prompt repetition of testing under ideal conditions.

  • dSeveral foods and medications may interfere with metanephrine analysis and should be avoided prior to testing. These are summarized in Supplementary Table S1.

  • eRecommended action based on plasma metanephrines:

    • –Confirm interfering agents were avoided prior to testing (Supplementary Table S1).

    • –If ≥4× upper limit of reference range: consistent with disease, proceed with imaging to localize lesion.

    • –If 2×–4× upper limit of reference range: repeat testing in 2 months.–If marginally elevated: repeat testing in 6 months or consider clonidine suppression test to exclude false positivity (74, 75).

  • fTwenty-four–hour urine fractionated metanephrines are an acceptable alternative to plasma metanephrines once patients are continent of urine.

  • gSpecific attention also paid to the kidneys due to rare risk of RCC.

  • hDepending on preferences of local radiologists, dedicated MRI of the neck may be preferred to inclusion in whole-body MRI. If this is the case, it should be performed concomitant with WBMRI.