Is there a role for positron emission tomography imaging in the early evaluation of prostate cancer relapse?

Abstract

The patient population with a rising prostate specific antigen (PSA) post-therapy with no evidence of disease on standard imaging studies currently represents the second largest group of prostate cancer patients. Little information is still available regarding the specificity and sensitivity of positron emission tomography (PET) tracers in the assessment of early biochemical recurrence. Ideally, PET imaging would allow one to accurately discriminate between local vs nodal vs distant relapse, thus enabling appropriate selection of patients for salvage local therapy. The vast majority of studies show a relatively poor yield of positive scans with PSA values o4 ng ml À1 . So far, no tracer has been shown to be able to detect local recurrence within the clinically useful 1 ng ml À1 PSA threshold, clearly limiting the use of PET imaging in the post-surgical setting. Preliminary evidence, however, suggests that 11 C-choline PET may be useful in selecting out patients with early biochemical relapse (PSA o2 ng ml À1 ) who have pelvic nodal oligometastasis potentially amenable to local treatment. The role of PET imaging in prostate cancer is gradually evolving but still remains within the experimental realm. Well-conducted studies comparing the merits of different tracers are needed.

Assessment of PET Tracer Uptake in Hormone-Independent and Hormone-Dependent Xenograft Prostate Cancer Mouse Models

“…In addition, the exact relation between prostate-specific antigen and 11 C-choline uptake is not known and the significance of clinical studies using 11 C-choline is seen as contradictory (17)(18)(19).…”

“…However, 11 C-choline is rarely used for primary diagnosis (16). Unfortunately, the exact biochemical background of choline metabolism still remains unclear and clinical PET studies validating 11 C-choline are often contradictory (17)(18)(19). After surgery, use of 11 C-choline often raises questions concerning differentiating relapsed malignant tissue from surgical necrosis or inflammation.…”

Dual-stage 18F-fluorocholine PET/CT scanning for biochemical recurrences of prostate cancer

“…Более того, при доброкачественной гипер-плазии ПЖ и простатите могут наблюдаться более высокие уровни накопления 18 F-ФДГ, чем при РПЖ [4,5,9]. Поэтому применение ПЭТ с 18 F-ФДГ может быть оправдано лишь для диагностики отдаленных метастазов у пациентов с установленной местной рас-пространенностью [22,34,36].…”

“…Согласно результатам ряда исследований ПЭТ с 11 С-холином достаточно точный и чувствительный метод в предоперационном стадировании, рестадиро-вании, диагностике рецидивов, метастазирования РПЖ и потенциально может исключить необходимость при-менения КТ и/или сканирования костей [32,33]. 18 F-фторхолин отличается несколько большей се-крецией через мочевыводящие пути, что создает опре-деленные трудности в визуализации ложа ПЖ по срав-нению с 11 С-холином, однако его большой период полураспада (110 мин против 20 мин) позволяет оце-нить динамику распределения РФП [31,34,35]. Уста-новлено, что увеличение или стабильное накопление 18 F-холина в выявленных патологических очагах (ложе ПЖ, лимфатические узлы -ЛУ) на 2-м этапе соответ-ствует злокачественным изменениям, в то время как уменьшение поглощения РФП связано с доброкачест-венным процессом (например, гиперплазия) [36][37][38][39].…”

Broadening the scope of Image-Guided Radiotherapy (IGRT)

“…For instance, in the context of early biochemical relapse following radical local treatment for prostate cancer, conventional imaging modalities are of little of no value in detecting local vs. nodal disease. New PET tracers such as 11 C-choline and 11 C-acetate may aid early detection of local recurrences or minimal nodal involvement vs. distant disease, thus effectively selecting patients who may be salvaged by highdose loco-regional radiotherapy [26,27].…”