A research reported that fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) surveillance will be useful for Hodgkin's lymphoma patients in the first 24 months after achieving remission of their cancer but not after that point.
We wanted to know if it really makes sense to scan patients every year because patients are asking for it, said Nicklaus Schaefer, MD, a postdoctoral fellow in the Department of Radiology at Johns Hopkins Medical Institute/Johns Hopkins University in Baltimore, Maryland, who conducted his research as a medical resident at the University Hospital of Zurich in Switzerland. Most of the patients that are being referred [for radiographic surveillance] are not symptomatic, and they don’t have any sign of recurrent disease.
Given the burden of radiation that additional scans represent and the fact that it is not clear if early detection of recurrent disease makes a difference in overall survival, Dr. Schaefer and colleagues retrospectively examined the utility of FDG-PET/CT surveillance.
When we looked at the data, we found that the symptoms and residual disease are very strong predictors [of recurrence], explained Dr. Schaefer, who proposed in his oral presentation that surveillance be practiced in the first 2 years after complete remission of Hodgkin’s lymphoma. Those predictors were time-dependent.
Among 135 Hodgkin’s lymphoma patients, 85 were asymptomatic and 50 were symptomatic, and all of whom had complete remission of their disease after receiving primary treatment, received FDG-PET/CT to screen for active disease. Positive FDG-PET/CT was seen in a total of 43 patients, and of that total, histologically confirmed relapse (positive predictive value, 0.98) was found in 42 patients. B-symptoms, new palpable masses, and new masses diagnosed by conventional imaging were the symptoms included.
Investigators found that asymptomatic patients with residual masses (n = 25) or with residual masses and advanced initial stage (n = 19) had more recurrences than patients with early-stage disease without residual masses (n = 27) (respectively, 6 vs 0 patients [P < .008] and 5 vs 0 patients [P < .001]).
Recurrence on FDG-PET/CT was exhibited by a total of 31 symptomatic patients and 30 had histological confirmation (positive predictive value, 0.97). No signs of recurrence were showed in the remainder of symptomatic patients and did not experience relapse during the follow-up period (mean, 22.7 months).
If we carefully select our patients, we will have a strong rate of detection of recurrence, said Dr. Schaefer. If we don’t use our resources wisely, they will be reduced.
Gregory Wiseman, MD, a consultant in nuclear medicine at the Mayo Clinic in Rochester, Minnesota, reported that the study design is a limitation, but it raises the issue of a lack of standardization in using surveillance among Hodgkin’s lymphoma patients.
Some people use surveillance and some don’t, said Dr. Wiseman. [The study] is retrospective, so it makes it a little bit harder to interpret. What we really need to do is conduct a prospective study of patients who are followed [with FDG-PET/CT] and those who aren’t to determine how useful it is. It is still possible because it’s not routine that these patients undergo surveillance.
Dr. Wiseman explained that this prospective trial would also separate Hodgkin’s lymphoma patients who have received radiation treatment from those who have not. He also noted that the effects of radiation therapy can affect the outcomes of FDG-PET/CT imaging.
All the patients in this study had chemotherapy, said Dr. Wiseman. People should not make conclusions based on patients in this study and apply it to patients who have undergone radiation.