Individualized dosimetry-based activity reduction of 9°Y-DOTATOC prevents severe and rapid kidney function deterioration from peptide receptor radionuclide therapy.

PURPOSE: Assessment of kidney function evolution after (90)Y-DOTATOC peptide receptor radionuclide therapy (PRRT) with capped activity administration based on a 37-Gy threshold of biological effective dose (BED) to the kidney. METHODS: In a prospective phase II study, patients with metastasized neuroendocrine tumours were evaluated for therapy using 185 MBq (111)In-pentetreotide with amino acid coinfusion. Planar whole-body images were acquired at four time-points after injection and kidney volumes were measured using CT/MRI. BED to the kidneys was estimated using an extended BED formula and biexponential renal clearance. Based on published BED dose-toxicity relationships, we allowed a maximal kidney BED of 37 Gy; if the calculated BED exceeded 37 Gy, treatment activity was reduced accordingly. Kidney function was assessed at baseline and at 18 months, predominantly using (51)Cr-EDTA. The rate of renal function decline was expressed as annual glomerular filtration rate loss (aGFRL). RESULTS: Only 22 of 50 patients reached the 18-months time-point, with most missing patients having died due to disease progression. In the 22 patients who reached 18 months, no rapid kidney function deterioration was observed over the 18 months, aGFRL >33% was not seen, and only three patients showed an increase of one toxicity grade and one patient an increase of two grades. No significant correlations between kidney volume (p = 0.35), baseline GFR (p = 0.18), risk factors for renal function loss (p = 0.74) and aGFRL were observed. Among the 28 patients who did not reach 18 months, one developed grade 4 kidney toxicity at 15 months after PRRT. CONCLUSION: Prospective dosimetry using a 37 Gy BED as the threshold for kidney toxicity is a good guide for (90)Y-DOTATOC PRRT and is associated with a low risk of rapid renal function deterioration and evolution to severe nephrotoxicity.

Somatostatin-receptor-based imaging and therapy of gastroenteropancreatic neuroendocrine tumors.

Somatostatin receptor imaging (SRI) with [(111)In-DTPA(0)]octreotide has proven its role in the diagnosis and staging of gastroenteropancreatic neuroendocrine tumors (GEPNETs). Newer radiolabeled somatostatin analogs which can be used in positron emission tomography (PET) imaging, and which have a higher affinity for the somatostatin receptor, especially receptor subtype-2, have been developed. It would be desirable, however, if one radiolabeled analog became the new standard for PET imaging, because the current application of a multitude of analogs implies a fragmented knowledge on the interpretation of the images that are obtained in clinical practice. In our view, the most likely candidates for such a universal PET tracer for SRI are [(68)Ga-DOTA(0),Tyr(3)]octreotate or [(68)Ga-DOTA(0),Tyr(3)]octreotide. Treatment with radiolabeled somatostatin analogs is a promising new tool in the management of patients with inoperable or metastasized neuroendocrine tumors. Symptomatic improvement may occur with all (111)In-, (90)Y-, or (177)Lu-labeled somatostatin analogs that have been used for peptide receptor radionuclide therapy (PRRT). The results that were obtained with [(90)Y-DOTA(0),Tyr(3)]octreotide and [(177)Lu-DOTA(0),Tyr(3)]octreotate are very encouraging in terms of tumor regression. Also, if kidney protective agents are used, the side effects of this therapy are few and mild, and the median duration of the therapy response for these radiopharmaceuticals is 30 and 40 months respectively. The patients' self-assessed quality of life increases significantly after treatment with [(177)Lu-DOTA(0),Tyr(3)]octreotate. Lastly, compared to historical controls, there is a benefit in overall survival of several years from the time of diagnosis in patients treated with [(177)Lu-DOTA(0),Tyr(3)]octreotate. These data compare favorably with the limited number of alternative treatment approaches. If more widespread use of PRRT can be guaranteed, such therapy may well become the therapy of first choice in patients with metastasized or inoperable GEPNETs.

Clinical application of low dose-rate brachytherapy combined with simultaneous mild temperature hyperthermia.

BACKGROUND: Recent biological research has shown that mild temperature hyperthermia (MTH) around 41 degrees C simultaneously combined with low dose-rate irradiation (LDRI) is an effective treatment modality for cancer. The aim of the study was to assess the clinical usefulness of a combination of MTH and simultaneous low dose-rate brachytherapy. MATERIALS AND METHODS: Seven superficial and 8 deep-seated tumors were included in this protocol. Two tumors had no previous treatment and the remainder were recurrent tumors which had arisen from previously treated sites. The average major diameters of superficial and deep tumors were 8.6 and 7.0 cm, respectively. The average values for Tmin in superficial and deep tumors were 41.5 and 40.7 degrees C, respectively. Brachytherapy was delivered by 137Cs and/or 192Ir LDRI sources. RESULTS: For superficial tumors, six of the seven tumors responded to the treatment (4 achieved CR, 2 PR, 1 NC) and four tumors did not recur within the follow-up period of 5-15 months. All of the deep tumors responded and 5 achieved CR, 3 PR. Four tumors recurred 4-17 months after the treatment and the remainder showed no local recurrence within the follow-up period of 4-31 months. CONCLUSION: MTH simultaneously combined with LDRI was an effective method for treating progressive and bulky tumors with a previous treatment history.

Adjuvant therapy for gastrointestinal cancer.

Perioperative adjuvant treatment with chemotherapy or radiation therapy has been investigated for colon, rectal, gastric, esophageal, and pancreatic cancers. To date, conclusive benefit had been shown only for colon and rectal cancers. Demonstration that adjuvant therapy can result in reductions in tumor recurrence and cancer death after surgery for large bowel cancer is a major therapeutic advancement, and current clinical trials may yield further incremental improvements. Standard recommendations for adjuvant treatment exist for patients with colorectal cancers who do not take part in these clinical studies. Several factors complicate the assessment of adjuvant therapy for gastric, esophageal, and pancreatic cancers. Some regimens have appeared to offer promise of improved postsurgical outcome, but no adjuvant treatment has established benefit in these sites.