The metabolic adaptation evoked by arginine enhances the effect of radiation in brain metastases.

Selected patients with brain metastases (BM) are candidates for radiotherapy. A lactatogenic metabolism, common in BM, has been associated with radioresistance. We demonstrated that BM express nitric oxide (NO) synthase 2 and that administration of its substrate l-arginine decreases tumor lactate in BM patients. In a placebo-controlled trial, we showed that administration of l-arginine before each fraction enhanced the effect of radiation, improving the control of BM. Studies in preclinical models demonstrated that l-arginine radiosensitization is a NO-mediated mechanism secondary to the metabolic adaptation induced in cancer cells. We showed that the decrease in tumor lactate was a consequence of reduced glycolysis that also impacted ATP and NAD+ levels. These effects were associated with NO-dependent inhibition of GAPDH and hyperactivation of PARP upon nitrosative DNA damage. These metabolic changes ultimately impaired the repair of DNA damage induced by radiation in cancer cells while greatly sparing tumor-infiltrating lymphocytes.

Phase I/II study of selective cyclooxygenase-2 inhibitor celecoxib as a radiation sensitizer in patients with unresectable brain metastases.

PURPOSE: The primary goal of this phase I/II study was to evaluate the feasibility, safety and efficacy of celecoxib administered concomitant to radiotherapy to treat unresectable BM. PATIENTS AND METHODS: Patients with measurable BM by CT or MRI, unresectability criteria by a neurosurgeon and RPA-RTOG class II were eligible. Celecoxib was administered at 400 mg/day during the entire course of radiotherapy. All patients were irradiated with 60Co beams to whole-brain dose of 32 Gy (20 fractions of 1.6 Gy each two times a day with a 6 h interval between treatments) followed by a 22.4 Gy boost (same fractionation schedule) over evident lesions. RESULTS: Twenty-seven patients were treated. The concurrent regimen was well tolerated with 15 cases of mild dyspepsia. Alopecia (NCI grades 1-2) was the most important side effect. Three patients presented rash/desquamation of moderate intensity. Radiological responses occurred in 18 of 25 valuable patients (72), with five complete responses (CR). Symptomatic responses were reported in 25 of 27 patients (92.6), with 20 CR. The overall response rate (considering complete plus partial responses) was 66.7. Percentile 50 for time-to-progression, time-to-neurological-progression and functional-independence-time were 3, 6.25 and 6.7 months, respectively. Median survival time was 8.7 months. CONCLUSION: Our initial results suggest that radiotherapy plus celecoxib is safe and a possible active treatment for patients with BM. Further investigation in a randomized trial is warranted to validate its clinical utility.

Potential utility of the peripheral analgesic properties of morphine in stomatitis-related pain: a pilot study.

To determine the potential clinical utility of peripheral opioid action using a clinical model of cancer treatment-induced inflammation and pain that allowed for topical application of morphine in the damaged tissue (oral mucosa). This pilot study followed a two blocks design. Ten patients with painful oral mucositis were enrolled in the first block (dose-response relationship finding) and randomized in two groups to receive oral rinses with 15 ml of either 1 per thousand or 2 per thousand morphine solution. Twenty-two patients were enrolled into the second block (efficacy and safety determination). Additionally, serum concentrations of morphine were measured in five representative patients. In the first block (n=10) a dose-response relationship for topical morphine was found. Rinses with 2 per thousand -morphine solution showed better pain relief (median 80%, range 70-80%) than those with 1 per thousand (median 60%, range 55-70%; P=0.0238). Therefore, subsequent patients enrolled for the second block (n=22) received oral rinses with 2 per thousand -morphine solution. In these patients the time to good (>or=50%) or to complete (100%) pain relief was 28 (+/-12)min after the first mouthwash, and the duration of relief was on average 216 (+/-25)min. Twenty patients (90%) received the successive mouthwashes every 3 h and 10% of them every 2 h. The duration of severe pain at the moment of swallowing was 5.17 (+/-1.47) days. Only six patients needed supplementary analgesia, and the time elapsed before the first supplemental analgesic was 1.18 (+/-0.8) days. The duration of severe functional impairment was 1.52 (+/-1.31) days, thus allowing us to feed the patient by mouth with liquid-food supplementation. During our experiment no systemically active detectable concentrations of morphine were found (GC-MS analysis). The most important side effect attributable to morphine mouthwashes was burning/itching sensation (very mild to mild intensity). Patients with painful chemoradiotherapy-induced stomatitis could be alleviated using topical morphine mouthwashes.

Effect of topical morphine for mucositis-associated pain following concomitant chemoradiotherapy for head and neck carcinoma.

BACKGROUND: Oral mucositis is the dose-limiting toxicity for patients receiving concurrent chemoradiotherapy regimens for tumors of the head and neck area. Currently, the management of established mucositis includes the use of topical anesthetics and systemic analgesics. Based on the clinical evidence of pain alleviation by topical morphine in patients with some inflammatory and painful conditions, a clinical study was undertaken to determine this effect on mucositis-associated pain. METHODS: Twenty-six patients with head and neck malignancies treated with concomitant chemoradiotherapy for head and neck carcinoma who had severe painful mucositis (World Health Organization Grade 2 or higher) were enrolled. Patients were randomly assigned to morphine mouthwash (MO; 14 patients) or magic mouthwash (MG), a mixture of equal parts of lidocaine, diphenhydramine, and magnesium aluminum hydroxide (12 patients). RESULTS: The duration of severe pain was 3.5 days less in the MO group compared with the MG group (P = 0.032). The intensity of oral pain was also significantly lower in the MO group compared with the MG group (P = 0.038). No patient in the MO group required third-step opiates for alleviation of the mouth pain. There was a significant difference in duration of severe functional impairment (P = 0.017). Five patients in the MG group complained of local side effects and only one in the MO group (P = 0.007). CONCLUSIONS: For patients with head and neck carcinomas receiving concomitant chemoradiotherapy, MO is a simple and effective treatment to decrease the severity and duration of pain and the duration of functional impairment.