Long-Term Results of Induction Chemotherapy Followed by 50 Gy Radiation Therapy Alone for Low-Risk HPV-Positive Oropharynx Cancer

PURPOSE/OBJECTIVE(S)

The standard of care for non-operative management of human papillomavirus-related oropharynx cancer (HPV-OPC) consists of concurrent cisplatin chemotherapy with radiotherapy (RT) to a total dose of 70 Gy. While the oncologic outcomes of this treatment approach have been excellent, there are considerable acute and late toxicities. Here, we report the 5-year survival and toxicity outcomes of 2 prospective HPV-OPC response-adapted de-escalation trials, in which low-risk (LR) patients were treated with dose-reduced RT to 50 Gy, without concurrent chemotherapy.

MATERIALS/METHODS

Patients with LR HPV-OPC and ≥50% response to induction by RECIST 1.1 treated per 2 prospective phase II trials as well as on a prospective cohort registry were included for analysis. Patients were considered LR if the following criteria were met: T1-T3, N0-N2b (AJCC 7th edition), and ≤20 pack-year smoking history. Patients were treated with induction chemo- or chemoimmunotherapy followed by RT alone to 50 Gy. In the early trial iteration, patients underwent a planned neck dissection following RT to confirm pathologic clearance of lymph nodes. Clinicodemographic characteristics were summarized using descriptive statistics. Overall survival (OS), progression-free survival (PFS), and local control (LC) were estimated using the Kaplan-Meier method.

RESULTS

From January 2015 through March 2020, 73 patients met LR criteria, of which, 54 (74%) had ≥50% response by RECIST and were de-escalated to RT alone. The median follow-up was 58 (range 10-92) months. The median age was 58 (range 38-84) years, and 92.6% were male. 57.4% of patients never smoked, and 42.6% smoked no more than 20 pack-years. The primary site was tonsil for 53.7% and base of tongue for 46.3%. 24.1% were T1, 53.7% were T2, and 22.2% were T3. 1.9% were N0, 5.6% were N1, 11.1% were N2a, and 81.5% were N2b. The 5-year OS, PFS, and LC were 96.3% (95% CI 91.3%-100%), 96.2% (95% CI 91.2%-100%), and 98.1% (95% CI 94.6%-100%), respectively. 2 (3.7%) patients required a G-tube during RT and none at 1 year following completion of RT. Of the 30 patients with a planned neck dissection, 2 (6.7%) had residual pathologic nodal disease.

CONCLUSION

With a median follow-up of 5 years, this analysis demonstrates excellent long-term local control, survival, and swallowing function among patients with low-risk HPV+ oropharynx cancer treated with induction systemic therapy followed by radiotherapy to 50 Gy without concurrent chemotherapy, including a large proportion of patients with N2b disease. Chemo-selection provides a means of identifying a favorable cohort of HPV+ oropharynx cancer patients who can safely receive RT dose de-escalation. Further work is needed to identify this population by other means, including radiographic and genomic factors.

Definitive Chemoradiotherapy for Salivary Gland Cancers

PURPOSE/OBJECTIVE(S)

Surgical resection is the standard of care for salivary gland tumors of the head and neck. The role of radiotherapy is typically reserved for the adjuvant setting in those patients with high risk factors on surgical pathology. Surgical resection in some cases may lead to significant impairment in speech or swallowing due to location of the primary tumor. In other cases, patients may not be medically able to receive an oncologic resection. Our institution has developed a protocol for organ preservation for well-selected salivary gland malignancies. Here we report disease outcomes of salivary gland cancer patients treated with definitive chemoradiotherapy.

MATERIALS/METHODS

We retrospectively reviewed all salivary gland cancer patients at our institution who received definitive chemoradiation from January 1990 to December 2019. Chemoradiation typically consisted of 4 to 6 alternating weekly cycles of paclitaxel (100 mg/m2 on d1), infusion 5-fluorouracil (600 mg/m2/d on d0-5), hydroxyurea (500 mg PO BID), and either 1.8 Gy or 2 Gy daily or 1.5 Gy twice-daily irradiation followed by a 9-day treatment break (TFHX). The Kaplan-Meier method was used to estimate rates of locoregional control (LRC), distant metastasis-free survival (DMFS), and overall survival (OS).

RESULTS

Nineteen patients met eligibility criteria and were included for analysis. 53% of patients had adenoid cystic histology. Salivary duct, mucoepidermoid, acinic cell, and myoepithelial histologies each were represented by 10.5% of patients. About 26% of tumors were located in the nasopharynx, 21% in the base of tongue and 26% in the parotid. 74% of the patients were node negative and 53% of patients had stage IVA disease. T3 disease occurred in 26.3% while T4a and T4b disease occurred in 31.6% each. Median follow-up was 45.8 (IQR: 29-66) months. 47% of patients were treated using a twice daily approach, while 53% were treated with daily fractionation with a median dose of 72 Gy (IQR: 70-75). Three-year locoregional control (LRC), distant-metastasis free survival (DMFS), and overall survival (OS) were 93%, 76%, and 81% respectively. Eight of nine distant failures had T4a/T4b disease. Accounting for competing risk of death, local failure was 5.6% at three years. The most common acute complications were grade 2-3 mucositis (74%) and skin toxicity (47%). One patient discontinued chemoradiation due to severe hand foot mouth syndrome. 42% of patients had late toxicity of xerostomia.

CONCLUSION

Promising organ preservation is seen with concurrent chemoradiation for salivary gland cancer patients. Further prospective study of organ preservation in salivary gland cancers is warranted.

Involved Site Radiotherapy in HPV Positive Oropharyngeal Cancer: Patterns of Failure Analysis Across Prospective De-Escalation Trials

PURPOSE/OBJECTIVE(S)

HPV-associated oropharyngeal cancers (HPV+OPC) have a favorable prognosis with ongoing efforts to reduce long term toxicity while maintaining oncologic outcomes. One method under investigation includes lowering the elective radiation dose or in some cases omitting radiation to elective lymphatic nodal stations. Furthermore, pre-clinical evidence demonstrates that elective nodal irradiation blunts the anti-tumor immune response in head and neck cancer. This is a pooled secondary analysis reporting patterns of failure in patients (pts) with HPV+OPC enrolled on consecutive induction chemo- or chemoimmunotherapy (IC) based response-adaptive de-escalation trials and treated with involved-site radiotherapy (ISRT).

MATERIALS/METHODS

Pts treated on two prospective phase II trials as well as on a prospective cohort registry were included for analysis. Pts with ≥ 50% response to IC based on RECIST 1.1 who received de-escalated definitive radiotherapy (RT) or concurrent chemoradiation (CRT) with ISRT were evaluable. Pts with locally advanced low risk or high-risk HPV+OPC (LR and HR, respectively) were eligible for enrollment. Pts were considered to have HR if at least one of the following criteria was met: T4 primary, N2c-N3 disease (AJCC 7th ed.), or > 10-20 pack years smoking. In the first trial, pts with ≥ 50% response to IC received RT to gross disease plus a 1.5 cm margin (PTV1) and to the next echelon of uninvolved nodes (PTV2). Pts with LR received 50 Gy in 2 Gy daily fractions without chemotherapy; pts with HR received 30 Gy in 1.5 Gy BID fractions to PTV2 with a 15 Gy sequential boost to PTV1 with CRT. In the subsequent trial, pts with ≥ 50% response received RT to PTV1 alone to 50 Gy in 2 Gy daily fractions; concurrent CRT was included if pts had HR. Survival was estimated using the Kaplan Meier method for progression free survival (PFS), locoregional PFS (LRPFS), and overall survival (OS). Patterns of failure analysis was performed by comparing RT plans to radiographic surveillance scans.

RESULTS

Of 172 evaluable pts, 119 (69.2%) achieved a ≥ 50% response to IC and received definitive ISRT. 45 (37.8%) pts evaluated received RT to gross disease only plus margin without the next nodal echelon included. With a median follow up of 46 (IQR 34-65) months, 3-year PFS, LRPFS, and OS with their 95% confidence intervals were 96.2% (90.1-98.5%), 97.1% (91.1-99.0%), and 96.2% (90.3-98.6%), respectively. All locoregional failures were in-field and in the high dose region. No failures were observed in the RT omitted neck.

CONCLUSION

This prospective experience demonstrates feasible volume de-escalation using IC response-based selection with progressively smaller elective volumes over time. Notably, despite a marked reduction in elective treatment volume, there were no regional out-of-field failures. IC may allow for selection of pts with favorable tumor biology and microscopic disease sterilization in the regional nodes. Further efforts at elective nodal de-escalation are needed.

Radiomics Based Assessment of Tumor Infiltrating CD8 T-Cells Predicts Induction Systemic Therapy Response in HPV+ Oropharyngeal Cancer: Exploratory Analysis of Prospective Trials

PURPOSE/OBJECTIVE(S)

The adaptive immune system is increasingly recognized to be important for tumor control in HPV+ oropharyngeal cancer (HPV+OPC), and pre-clinical models suggest tumor specific T-cell priming occurs in draining lymph nodes. De-escalation strategies incorporating T-cell infiltration present a novel prognostic biomarker. The purpose of this study was to examine the utility of a validated radiomics model of CD8 T-cell infiltration within the framework of 2 prospective HPV+OPC response-adaptive de-escalation trials. We hypothesized that nodal radiomics scores (RS) would be correlated with response to induction systemic therapy.

MATERIALS/METHODS

Patients enrolled on 2 prospective phase II response adapted de-escalation trials for low- and high-risk HPV+OPC were included in the analysis. Patients received induction chemotherapy and chemoimmunotherapy in trials 1 and 2, respectively. Primary tumors and nodes were retrospectively delineated on diagnostic CT scans before and after induction therapy to ascertain volumetric tumor burden & response. RS were generated on pre-induction scans for both primary tumors and nodes. RS and tumor response were dichotomized using a 50% threshold (high vs low, responder vs non-responder, respectively). Linear regression was used to evaluate the correlation between % volume change in tumor burden and RS. Fisher's exact test was used to evaluate concordance between RS and tumor response.

RESULTS

A total of 87 patients (N = 47 Trial 1, N = 40 Trial 2) were evaluable. The mean post-induction therapy reduction in primary and nodal volumetry was 80.7% and 67% respectively. Primary and nodal RS were not associated with primary (T1/T2 vs T3/T4) or nodal stage (N1-N2b vs N2c-N, p > 0.10 both). Both primary and nodal RS were correlated with % volume change, r = 0.24 (p = 0.034) and r = 0.37 (p = 0.002), respectively. The mean difference in % volume change in primary and node, using the RS, was 11.13% (p = 0.015) and 17. 69% (p = 0.004). There was no association between primary tumor RS and total lesion responder status (p = 0.312). However, there was an association between high vs low nodal RS and total lesion responder status (p = 0.005).

CONCLUSION

This is the first report of a validated radiomics score of CD8-T cell infiltration in HPV+OPC to predict response to systemic therapy. While radiomics scores in both the primary and nodes were associated with percent volume response, this association was stronger in nodes. Higher nodal radiomics scores were associated with improved volume reduction in total lesion burden. This effect however was not observed in the primary tumor. CD8-T cell infiltration in nodes, but not in the primary tumor, was associated with overall tumor response after systemic induction therapy in HPV+ oropharyngeal cancer.

A multicenter, open-label, randomized, phase II study of cediranib with or without lenalidomide in iodine 131-refractory differentiated thyroid cancer

BACKGROUND

Multitargeted tyrosine kinase inhibitors (TKIs) of the vascular endothelial growth factor receptor (VEGFR) pathway have activity in differentiated thyroid cancer (DTC). Lenalidomide demonstrated preliminary efficacy in DTC, but its safety and efficacy in combination with VEGFR-targeted TKIs is unknown. We sought to determine the safety and efficacy of cediranib, a VEGFR-targeted TKI, with or without lenalidomide, in the treatment of iodine 131-refractory DTC.

PATIENTS AND METHODS

In this multicenter, open-label, randomized, phase II clinical trial, 110 patients were enrolled and randomized to cediranib alone or cediranib with lenalidomide. The primary endpoint was progression-free survival (PFS). Secondary endpoints included response rate, duration of response, toxicity, and overall survival (OS). Patients (≥18 years of age) with DTC who were refractory to further surgical or radioactive iodine (RAI) therapy as reviewed at a multispecialty tumor board conference, and evidence of disease progression within the previous 12 months and no more than one prior line of systemic therapy were eligible.

RESULTS

Of the 110 patients, 108 started therapy and were assessable for efficacy. The median PFS was 14.8 months [95% confidence interval (CI) 8.5-23.8 months] in the cediranib arm and 11.3 months (95% CI 8.7-18.9 months) in the cediranib with lenalidomide arm (P = 0.36). The 2-year OS was 64.8% (95% CI 43.3% to 86.4%) and 75.3% (95% CI 59.4% to 91.0%), respectively (P = 0.80). The serious adverse event rate was 41% in the cediranib arm and 46% in the cediranib with lenalidomide arm.

CONCLUSIONS

Single-agent therapy with cediranib showed promising efficacy in RAI-refractory DTC similar to other VEGFR-targeted TKIs, while the addition of lenalidomide did not result in clinically meaningful improvements in outcomes.

The chondrogenic differentiation potential of dental pulp stem cells

Dental pulp stem cells (DPSCs) are particularly promising for tissue engineering (TE) due to the ease of their isolation procedure, great expansion potential and capability to differentiate towards several cell types of the mesodermal, ectodermal and endodermal lineages. Although several studies hint that DPSCs exhibit potential for cartilage tissue formation, the chondrogenic potential of DPSCs has only been marginally explored. Thus, the aim of the present study was to closely investigate the chondrogenic differentiation capacity of DPSCs for TE applications. More specifically, the potential of DPSCs for engineering hyaline and fibrous cartilage was determined. DPSCs obtained from 7 human molars were expanded and chondrogenically differentiated in a 3D pellet culture model. After 21 d of differentiation with chondrogenic stimuli, DPSCs displayed glycosaminoglycan, aggrecan and limited collagen type II deposition. Cells presented an elongated morphology and produced a collagen-rich extracellular matrix, with a predominance of collagen type I in most of the samples, a characteristic of fibrous cartilage tissue. Variations in the administration periods of several chondro-inductive growth factors, including transforming growth factor beta 3, bone morphogenetic protein-2, -6, -7 and insulin-like growth factor-1, did not increase glycosaminoglycan or collagen type II deposition, typical markers of hyaline cartilage tissue. Furthermore, DPSCs could not be stimulated to go into hypertrophic chondrogenesis. These results indicated that under a large variety of chondro-inductive culture conditions, DPSCs could form fibrocartilaginous tissues but not hyaline cartilage. Thus, DPSCs represent a valuable cell source for the regeneration of fibrocartilage in joints.

Engineering of a complex bone tissue model with endothelialised channels and capillary-like networks

In engineering of tissue analogues, upscaling to clinically-relevant sized constructs remains a significant challenge. The successful integration of a vascular network throughout the engineered tissue is anticipated to overcome the lack of nutrient and oxygen supply to residing cells. This work aimed at developing a multiscale bone-tissue-specific vascularisation strategy. Engineering pre-vascularised bone leads to biological and fabrication dilemmas. To fabricate channels endowed with an endothelium and suitable for osteogenesis, rather stiff materials are preferable, while capillarisation requires soft matrices. To overcome this challenge, gelatine-methacryloyl hydrogels were tailored by changing the degree of functionalisation to allow for cell spreading within the hydrogel, while still enabling endothelialisation on the hydrogel surface. An additional challenge was the combination of the multiple required cell-types within one biomaterial, sharing the same culture medium. Consequently, a new medium composition was investigated that simultaneously allowed for endothelialisation, capillarisation and osteogenesis. Integrated multipotent mesenchymal stromal cells, which give rise to pericyte-like and osteogenic cells, and endothelial-colony-forming cells (ECFCs) which form capillaries and endothelium, were used. Based on the aforementioned optimisation, a construct of 8 × 8 × 3 mm, with a central channel of 600 µm in diameter, was engineered. In this construct, ECFCs covered the channel with endothelium and osteogenic cells resided in the hydrogel, adjacent to self-assembled capillary-like networks. This study showed the promise of engineering complex tissue constructs by means of human primary cells, paving the way for scaling-up and finally overcoming the challenge of engineering vascularised tissues.

Magnetic coupling at rare earth ferromagnet/transition metal ferromagnet interfaces: A comprehensive study of Gd/Ni

Thin film magnetic heterostructures with competing interfacial coupling and Zeeman energy provide a fertile ground to study phase transition between different equilibrium states as a function of external magnetic field and temperature. A rare-earth (RE)/transition metal (TM) ferromagnetic multilayer is a classic example where the magnetic state is determined by a competition between the Zeeman energy and antiferromagnetic interfacial exchange coupling energy. Technologically, such structures offer the possibility to engineer the macroscopic magnetic response by tuning the microscopic interactions between the layers. We have performed an exhaustive study of nickel/gadolinium as a model system for understanding RE/TM multilayers using the element-specific measurement technique x-ray magnetic circular dichroism, and determined the full magnetic state diagrams as a function of temperature and magnetic layer thickness. We compare our results to a modified Stoner-Wohlfarth-based model and provide evidence of a thickness-dependent transition to a magnetic fan state which is critical in understanding magnetoresistance effects in RE/TM systems. The results provide important insight for spintronics and superconducting spintronics where engineering tunable magnetic inhomogeneity is key for certain applications.

Treatment of central giant cell granuloma of the jaw with calcitonin

Giant cell granuloma of the jaw is a benign lesion that may cause local destruction of bone and displacement of teeth. The common therapy is curettage or resection, which may be associated with loss of teeth and, in younger patients, loss of dental germs. An alternative treatment has recently been introduced, in which patients receive a daily dose of calcitonin. Four patients who have been treated with calcitonin in various concentrations for at least 1 year are reported. In all patients, complete remission of the giant cell granuloma was observed, without signs of recurrence. The working mechanism of calcitonin is discussed, as are length of treatment and optimal dose.

Prospective comparison of rapid urease tests (PyloriTek, CLO test) for the diagnosis of Helicobacter pylori infection in symptomatic children: a pediatric multicenter study

OBJECTIVE

Rapid urease tests are reliable methods to diagnose Helicobacter pylori (HP) infection in the endoscopy suite. The PyloriTek test kit is a new rapid urease test that has the advantage of a 1-h final reading. The aim of this study was to compare the accuracy of PyloriTek and the test in the diagnosis of H. pylori infection in children.

METHODS

Children from four different pediatric gastroenterology centers were recruited prospectively into the study. These children were >5 yr old and had an upper endoscopy procedure. Antral biopsies were examined for both rapid urease tests in the endoscopy suite, and others were sent for routine histological examination.

RESULTS

A total of 242 children were recruited into the study over approximately 1 yr. The concordance between PyloriTek and CLO test was 98% (238 of 242). Twenty-five children were positive for HP organisms by PyloriTek and CLO test, whereas four children were positive by PyloriTek but negative by CLO test. PyloriTek was comparable to CLO test for the diagnosis of HP organisms and HP-associated gastritis. Moreover, in 48% of the positive results, PyloriTek gave significantly faster results than CLO test.

CONCLUSIONS

We conclude that PyloriTek is an appropriate rapid urease test to use in children and may have an advantage over the CLO test because of its shorter reading time.

Crohn's disease of the prepuce in a 12-year-old boy: a case report and review of the literature

We report a case of Crohn's disease with involvement of the foreskin in a 12-year-old boy. One year previously, on the basis of clinical features (diarrhea with blood, perianal fissures) and histologic examination, a diagnosis of Crohn's disease was made. Subsequently, he developed phimosis and balanitis and underwent circumcision. Sections submitted from the foreskin revealed noncaseating granulomatous inflammation consistent with Crohn's disease. Crohn's disease with involvement of the genitalia is unusual. Only 26 cases including our case have been reported in the scientific literature. We have analyzed these cases with emphasis on gender, age, clinical features, duration of Crohn's disease, and probable mode of spread to the genitalia. Careful examination of sections from genital lesions, including those submitted from the foreskin, is essential to detect small isolated granulomas that may then lead to the diagnosis of inflammatory bowel disease.

[Calcitonin therapy in large or recurrent central giant cell granulomas of the lower jaw]

In three patients, boys aged 4 and 3 years and a woman aged 18 years, central giant cell granuloma of the mandible was diagnosed. As an alternative to mutilating surgery all three patients were treated with calcitonin, the second one when he was 16 years old and after the tumour had recurred 5 times following extirpation. After an average therapy of 14 months, no recurrences were encountered. Mean follow-up was 8 months. In local biopsies mature bone tissue was seen during the first 3 months of therapy, slight changes of the levels of procollagen peptide type 1, parathormone and hydroxyproline in 24-hour urine were noticed, all within the normal limits. During and after termination of therapy serum calcium, phosphate and parathormone stayed within the normal range. Side effects consisted of flushes, nausea and vomiting. Calcitonin is still an experimental therapy for central giant cell granuloma, but may be a good alternative to mutilating surgery in case of large or multiple recurring tumours.

Active and passive cigarette smoke exposure and cervical intraepithelial neoplasia

This case-control analysis presents odds ratios for active and passive cigarette smoke exposure and cervical intraepithelial neoplasia of levels II and III (CIN II and CIN III) while controlling for confounders. From 1987 to 1988, 103 biopsy-conformed incident cases of CIN II or III and 268 controls with normal cervical cytology were enrolled. Seventy % of cases were cigarette smokers, while only 30% of controls had ever smoked. The adjusted odds ratio for current cigarette smoking was 3.4 (95% confidence interval, 1.7-7.0). The following confounders were included in logistic regression models: age, race, education, number of sex partners, contraceptive use, sexually transmitted disease history, and Pap smear history. The risk of CIN II/III increased with increasing years of cigarette smoking and with increasing pack-years of exposure. Smoking was associated more strongly with CIN III than CIN II. The effect of passive cigarette smoke exposure was explored separately for smokers and nonsmokers and was found not to be consistently associated with CIN II/III when controlling for confounders.

Low breath hydrogen production in post-diarrheic infants

Thirty hospitalized infants, aged 1 month to 15 months, who were more than 24 hours into a post-recovery period from diarrheic episodes were studied for breath hydrogen production due to intestinal lactulose fermentation. Only 16% of the infants demonstrated hydrogen production of greater than 20 parts per million (ppm) over the baseline. We conclude that a recovery period much longer than 24 hours from the last diarrheic episode is necessary to obtain any reliable data from breath hydrogen tests administered to infants.

Cobalamin malabsorption in three siblings due to an abnormal intrinsic factor that is markedly susceptible to acid and proteolysis

Three siblings presented in their second year of life with megaloblastic anemia that responded to parenteral cobalamin (Cbl). Schilling tests were less than 1%, correcting to 5 to 15% after addition of hog intrinsic factor (IF). Gastric acid analysis and gastric biopsies were normal by light and electron microscopy. Gastric juice contained less than 3 pmol/ml of Cbl-binding ability due to IF (normal, 10-34 pmol/ml) and less than 2 pmol/ml of IF when measured with a radioimmunoassay (RIA) using normal human IF-[57Co]Cbl and rabbit anti-human IF serum (normal, 17-66 pmol/ml). However, RIA employing rabbit anti-hog IF serum gave values of 4-13 pmol/ml of IF (normal, 11-33 pmol/ml). This material had an apparent molecular weight of 40,000 (normal IF = 70,000). The IF from gastric biopsies appeared normal in terms of Cbl-binding ability, ileal binding, molecular weight, and both RIAs. This IF differed from normal mucosal IF, in that it lost its Cbl-binding ability when incubated at 37 degrees C at acid pH or in the presence of pepsin or trypsin. This loss was retarded when [57Co]Cbl was bound to the IF before these incubations. The stabilizing effects of neutralization and Cbl were also demonstrated in vivo. Schilling tests for the siblings of 0.4, 0.5, and 1.0% increased to 2.7, 5.7, and 4.3% (P less than 0.05), respectively, when the Schilling tests were repeated with the addition of NaHCO3 and cobinamide (which allows Cbl to bind immediately to IF). We conclude that Cbl malabsorption in these children is due to an abnormal IF that is markedly susceptible to acid and proteolytic enzymes which cause a decrease in its molecular weight and Cbl-binding ability and a loss of antigenic determinants that are recognized by the anti-human IF serum.

A new simplified technique for pediatric anorectal manometry

Using a new simple technique that is well tolerated and rapid for assessing anal sphincter functions in pediatric patients with fecal incontinence and constipation, 86 patients with varying degrees of anorectal dysfunction were tested. A microtip pressure transducer was used for recording anal sphincter responses to rectal balloon distension. Results were obtained within 15 to 30 minutes. In 17 patients, the internal anal sphincter showed no response or positive spike to balloon distension, consistent with the manometric diagnosis of aganglionic megacolon. These findings were confirmed by absence of ganglion cells on rectal biopsy. Sixty-nine children had normal internal sphincter relaxation to rectal distension. Ganglion cells were present in nine biopsy specimens. In the remaining 60 patients, no further workup of aganglionosis was necessary. There were no false-positive or false-negative results. This technique has proved to be effective for initial evaluation of infants and children with constipation and encopresis.

Anorectal manometry: a new simplified technique

Several noninvasive techniques using anal balloons or catheter systems to measure anal sphincter function associated with rectal balloon distention have been used in differentiating functional constipation from aganglionic megacolon. We have developed a simplified method for anorectal manometry that uses a microtip pressure transducer to record anal sphincter responses. Seventy-three patients (51 children and 22 adults) with constipation have been studied with this technique. Normal responses of internal anal sphincter relaxation to rectal distentions were obtained in 60 patients (40 children and 20 adults), consistent with the diagnosis of functional constipation. Abnormal responses-no internal anal sphincter relaxation-were recorded in 13 patients (11 children and two adults), consistent with the diagnosis of Hirschsprung's disease. The manometric diagnosis was confirmed in all 21 patients biopsied. There were no false-positive or false-negative results. The technique is a simple, well tolerated, and rapid method for assessing anal sphincter function.