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Totally Implantable Venous Access Ports Systems for Patients Receiving Chemotherapy for Solid Tissue Malignancies: A Randomized Controlled Clinical Trial Examining the Safety, Efficacy, Costs, and Impact on Quality of Life

From the Departments of Medicine and Medical Microbiology, University of Manitoba; Manitoba Cancer Treatment and Research Foundation; and World Health Organization Collaborating Centre for Quality of Life Research in Cancer, Winnipeg, Manitoba, Canada.

Address reprint requests to E.J. Bow, MD, Room GD600, Health Sciences Centre, 820 Sherbrook St, Winnipeg, Manitoba, Canada R3A 1R9; email ebow{at}hsc.mb.ca

	ABSTRACT

TOP ABSTRACT INTRODUCTION PATIENTS AND METHODS RESULTS DISCUSSION REFERENCES

 
PURPOSE: To examine the safety, efficacy, costs, and impact on quality of life of venous access ports implanted at the outset of a course of intravenous cancer chemotherapy.

PATIENTS AND METHODS: Adults beginning a course of intravenous chemotherapy at two university-affiliated hospitals were randomly allocated to have venous access using a surgically implanted venous access port (Port-a-Cath; Pharmacia, Canada Inc, Montreal, Québec, Canada) or using standard peripheral venous access. All accesses were documented by number, route, purpose, and procedure duration. Outcome measurements included port complications, access strategy failure, access-related anxiety and pain, quality of life (Functional Living Index–Cancer [FLI-C]), and costs.

RESULTS: Port complication rates were low (0.23/1,000 days). Failure occurred in two (3.4%) of 59 port subjects and 16 (26.7%) of 60 controls (P = .0004) at a median period of 26 days after randomization (95% confidence interval, 8 to 92). Peripheral accesses in port subjects took less time, had less access-related anxiety and pain, and were less costly to perform than in controls. Allocation had no effect on FLI-C scores. Peripheral access failure correlated with allocation to the control group (P = .007), higher pain scores with intravenous (IV) starts (P = .003), and anxiety with IV starts (P = .01). Venous accessing overall in port patients was four times more costly than that in controls ($2,178/patient v $530/patient, respectively).

CONCLUSION: Ports were safe and effective but had no detectable impact on functional quality of life, despite less access-related anxiety, pain, and discomfort. Because only approximately one quarter of control patients ultimately required central venous access, economic considerations suggest that port-use policies should be based upon defined criteria of need.

	INTRODUCTION

TOP ABSTRACT INTRODUCTION PATIENTS AND METHODS RESULTS DISCUSSION REFERENCES

 
VENOUS ACCESS is a problem for patients receiving prolonged courses of cytotoxic therapy for solid tissue malignancies. Venous integrity may be compromised by venotoxic antineoplastic agent–induced inflammatory changes and trauma related to repetitive blood sampling. Accordingly, reliable peripheral venous access becomes progressively harder to achieve and even more difficult to maintain over the period of a 6- to 9-month course of chemotherapy.

Indwelling tunneled, externalized central venous catheters of the Hickman or Broviac types^1,2 and totally implantable central venous access port systems³ have been advocated to improve venous access reliability, reduce the discomfort and anxiety associated with repetitive venous cannulation, and improve the overall quality of life. Externalized central venous catheter systems have the advantages of ease of implantation and reliable, multilumen venous access but the disadvantages of requiring frequent maintenance to maintain patency, a high incidence of malfunction due to thrombotic occlusion,⁴ a high risk of associated infection due to the endogenous skin microflora,^5,6 and, for reasons of safety, a requirement for some activity restrictions.⁷ Totally implantable venous access port systems have several advantages over externalized indwelling catheter systems,^7,8 including reliable venous access, a requirement for only monthly flushing and anticoagulation to maintain patency, fewer restrictions on activities such as bathing, and a relatively low incidence of infection and malfunction compared with externalized systems.^6,7,9-13

It is common practice to implant these devices in patients beginning a course of chemotherapy to avoid potential peripheral venous accessing problems; however, there have been no prospective, randomized, controlled clinical trials evaluating the advantages and disadvantages of this strategy. Accordingly, we designed and conducted a study to critically examine the safety, efficacy, costs, and impact on quality of life of totally implantable venous access port systems in patients receiving cytotoxic therapy for solid tissue malignancies.

	PATIENTS AND METHODS

TOP ABSTRACT INTRODUCTION PATIENTS AND METHODS RESULTS DISCUSSION REFERENCES

 
Between May 1988 and January 1991, 145 patients were referred for enrollment onto the study. Twenty-five patients either declined to participate or were deemed inappropriate for inclusion for the following reasons: refusal to undergo port implantation if allocated to the port arm (n = 11), inability to obtain informed consent because of a language barrier (n = 4) or because patients were overwhelmed by the diagnosis of cancer (n = 3), urgency to institute chemotherapy (n = 4), or treatment scheduled for rural or community hospitals where follow-up would be compromised (n = 3). A total of 120 adult patients with solid tissue malignancies were enrolled. Eligibility criteria included adults with a diagnosis of a solid tissue malignancy, beginning a course of intermittent bolus intravenous chemotherapy with an expected duration of treatment of 3 months or longer, with normal hemostatic parameters (prothrombin time, activated partial thromboplastin time, and platelet count), and with no end-organ failure. All patients gave written informed consent after interview and eligibility assessment. The study protocol was sanctioned by the University of Manitoba Committee on the Use of Human Subjects in Research and by the review boards of the participating institutions. During the study period, ports were not routinely available in the participating institutions except within this trial.

Study Design
This was an open, nonblinded, prospective, randomized, controlled trial. Eligible patients had standard peripheral venous access (control subjects) or an implantable venous access port system (study subjects), depending on computer-generated randomizations enclosed in sealed envelopes stratified by sex and underlying diagnosis. Patients were followed from the date of allocation until the completion of the planned course of chemotherapy. All venous accesses were recorded and classified according to route (that is, from the port or a peripheral site) and purpose (that is, intravenous [IV] start, phlebotomy for blood sample testing, simultaneous IV start and phlebotomy, and peripheral fingerprick with a blood lancet for complete blood counts). The presence or absence of access-related anxiety (based upon the presence of physical signs such as agitation, tachycardia, pallor, or sweating), tearfulness, voiced apprehension, or pain was recorded. The magnitude of pain and discomfort was recorded on a visual analog symptom distress scale (SDS) ranging from 0 (no pain or discomfort) to 100 (the worst pain imaginable). Whenever multiple attempts were required to achieve venous access, the mean SDS value for the attempts was recorded. Topical anesthesia was not used for accesses in this study. The time required to perform the venous access procedure was recorded in 5-minute increments; 0 to 5 minutes, more than 5 but 10 minutes, more than 10 but 15 minutes, more than 15 but 20 minutes, more than 20 but 25 minutes, more than 25 but 30 minutes, and more than 30 minutes. Quality of life was measured using a well-validated, standardized 22-item questionnaire, the Functional Living Index–Cancer (FLI-C), developed at the University of Manitoba.¹⁴

Patients who failed the assigned venous access strategy could cross over to the alternate arm. Criteria for port failure included documentation of irreversible port malfunction (occlusion, disconnection, or catheter fracture or rupture), port complications (eg, infection of the port pocket or persistent bacteremia), and patient intolerance of the port. To meet criteria for peripheral access failure, patients had to have at least two of the following: receipt of intravenous vesicant cytotoxic chemotherapy, difficulty in achieving reliable stable venous access (defined by the inability to maintain the integrity of the needle/vein access site, causing local pain, redness, swelling, or extravasation, or three unsuccessful attempts at venous cannulation on at least two successive occasions), or anxiety associated with venous cannulation, and at least one of the following: a requirement for at least once weekly venous access or two or more episodes of focal phlebitis at chemotherapy infusion sites. The principal investigator (E.J.B.) and study nurse (M.G.K.) carefully reviewed each patient with respect to the eligibility criteria before cross-over was allowed.

Materials
Standard sets of supplies for port accessing included two sterile towels, one alcohol swab, three povidone-iodine swabs, one pair of sterile gloves, one 20-mL syringe and one 10-mL syringe, an extension tubing set with a four-way stopcock, one Huber needle (Pharmacia, Canada, Inc, Montreal, Quebec, Canada), two 21-gauge needles, 100 U/mL heparin solution for anticoagulating the port reservoir, and one vial of sterile 0.9% saline for flushing the port reservoir and catheter. Port IV starts also required a 250-mL bag of 0.9% saline solution and IV tubing. Port phlebotomy required one additional 10-mL syringe for discard and one additional 20-mL syringe for the blood sample. Peripheral IV starts required one 22-gauge Jelco needle, one alcohol swab, IV tubing, and a 250-mL bag of 0.9% saline solution. Peripheral phlebotomy required two 20-mL syringes, two 22-gauge needles, one alcohol swabs, and a Band-Aid (Johnson & Johnson, New Brunswick, NJ). Fingerpricks required a blood lancet, an alcohol swab, and a sterile cotton ball for hemostasis.

The totally implantable titanium venous access port system (Port-a-Cath) with a silicone rubber catheter (OD 2.8 mm and ID 1.0 mm) was supplied by Pharmacia, Canada, Inc. The implantation procedure required the use of a no. 7-French peel-away introducer; a modified Seldinger technique was used for cannulation of the subclavian vein. Ports were implanted under local anesthesia by one of four surgeons who had agreed to follow a standardized implantation procedure.¹⁵ Only one port, implanted by a nonstudy surgeon, had to be replaced because of improper positioning. Port reservoirs were anticoagulated with 5 mL of heparin solution (100 U/mL) once every 4 weeks in the outpatient oncology clinics. Ports were accessed and dressed aseptically. Huber needles were changed weekly if indwelling venous access was required. The mean time used for port implantation in the operating theatre was 48.9 ± 15.9 minutes, whereas the mean total operating room time used was 79.7 ± 17 minutes. Prophylactic anticoagulants were not used during the course of this study.

Cost Analysis
Venous accessing costs were estimated in January 1992 Canadian dollars by examining the procedural costs and the expendable supply costs. Procedural costs were derived from the product of the median time required to perform the access (based upon the median of each of the 5-minute time intervals) and the hourly wage of an experienced registered nurse (based upon the median of the hourly pay scale for a nurse II, Health Sciences Centre, Winnipeg, Manitoba, Canada, January 1, 1992).

Port implantation costs included the port system ($510 on January 1, 1992; Pharmacia, Canada, Inc), the peel-away introducer kit ($55; Cook Catheter Systems, Bloomington, IN) used for central venous cannulation, the surgical fee ($130.50; Manitoba Health Care Commission, April 1, 1990), the operating room time, personnel and equipment ($16/minute multiplied by the time used for each patient; Health Sciences Centre, Winnipeg), and one postoperative chest radiograph ($25.84; Manitoba Health Care Commission, April 1, 1990). The standard supply kit costs for port IV starts and phlebotomy were $13.84 and $12.01, respectively. The supply kit costs for peripheral IV starts, phlebotomy, and fingerprick were $3.16, $1.03, and $1.03, respectively.

Quality of Life
The 22-item FLI-C questionnaire, which addresses patients' quality of life over the preceding 2-week period, was administered on the first day of each cycle of chemotherapy. Scores on the 1 to 7 response scale were recorded for each question. Subscale scores were derived from groups of questions comprising the five component scales measured by the FLI-C: physical well-being, psychologic well-being, hardship due to cancer, sociability, and nausea.¹⁴

Statistical Analysis
Demographics were compared using the two sample t test for continuous data and the ² test for categorical data. The time to failure for the venous access strategies was estimated for each study group using the Kaplan-Meier method¹⁶ and compared using the log-rank test. Factors influencing failure of peripheral access were examined using multiple linear regression. The FLI-C data were analyzed using the SAS-STAT Proc Mixed (SAS Institute, Cary, NC) procedure, which allows for intermittent missing data. Repeated-measures analysis of variance was undertaken by allocation and chemotherapy cycle for each subscale. The power analysis for this study was based upon estimates of the minimal clinically significant differences in the quality-of-life scores.^14,17 P values of less than .05 indicated statistical significance.

	RESULTS

TOP ABSTRACT INTRODUCTION PATIENTS AND METHODS RESULTS DISCUSSION REFERENCES

 
Patients
Sixty subjects were enrolled in both the study and control groups. One subject allocated to the study group received a port but was withdrawn from the study because of a change in the diagnosis of the underlying malignancy. Table 1 lists the demographic characteristics of the sample. Gynecologic malignancies accounted for the majority of diagnoses (76.7%). There were no statistical differences between the groups with respect to age, sex, underlying malignancy, institution, number of study days, classification of chemotherapy, or number of cycles of chemotherapy administered.

Venous Access Data
One hundred nineteen assessable subjects had a total of 3,017 venous accesses over 24,818 study days (study subjects, 12,691 days; control subjects, 12,127 days). The distribution of venous accesses is listed in Table 2. The majority (61.4%) of the 1,537 study group accesses were peripheral. Of these, the majority (86.8%) were peripheral phlebotomies for blood testing. The study group had the majority of IV starts established via the port. Fingerpricks were more frequent in study patients compared with controls (60 [6.3%] of 944 v 36 [2.6%] of 1,371, respectively; P < .0001).

Access Failure
Eighteen (15%) of 119 assessable patients failed the assigned venous access strategy. Two study patients (3.4%) crossed over to peripheral venous access because of port occlusion (day 64) and catheter fracture (day 386), compared with 16 controls (26.7%; P = .0004), of whom 14 received a port and two received an externalized central venous catheter. Inability to achieve stable reliable venous access was cited as the main reason for peripheral access failure in 14 controls (88%). Anxiety was cited as an additional significant component in 10 (71%) of these 14 patients. Anxiety and a requirement for total parenteral nutrition were cited as the main reasons for failure in the remaining two patients. The time to venous access failure is illustrated in Fig 1 (P = .002, log-rank test). Among control subjects who failed peripheral venous access and crossed over, failure occurred after a median period of 26 days (95% confidence interval, 8 to 92). Failure was correlated with allocation to the control group (P = .007), higher symptom distress scores on IV starts (P = .003), and anxiety with IV starts (P = .01) by multiple linear regression.

View larger version (18K): [in this window] [in a new window]   Fig 1. Kaplan-Meier time-to-failure plots (in days from randomization) for the two port group subjects on days 64 and 386 and for the 16 control group subjects (P = .002, log-rank test). Subjects were censored at the time they came off study.

Access-Related Anxiety and Pain
Table 2 summarizes these results according to type of access. Port access–related anxiety, tearfulness, apprehension, and pain were observed with similar frequencies among study and control (cross-over) patients, except that pain was reported more frequently by cross-over control patients who had a combined IV start plus phlebotomy procedures compared with study patients (34% v 16%, respectively; P = .03). Despite this, the SDS scores measuring the magnitude of pain and discomfort reported for port accesses in both groups were similar, which suggests that the more frequent reporting of pain with port accessing in the cross-over control subjects may have represented an element of sensitization by their previous negative experience with peripheral accessing. Pain with peripheral IV starts, phlebotomy, and fingerprick was reported more often among control than study patients (Table 2). Similarly, apprehension associated with peripheral IV starts and fingerpricks was also reported more often among controls. The SDS scores demonstrated greater pain and discomfort with peripheral accesses (particularly with phlebotomy) for control than for study subjects (22 ± 19 mm v 12 ± 10 mm, respectively; P < .0001). Further, the mean SDS scores for the 14 control subjects who failed peripheral accessing and subsequently required a port were higher than those for the remaining 44 control subjects who did not require central venous access (54 ± 37 mm v 24 ± 20 mm, P = .014).

Quality of Life
The analysis was based upon 92 subjects completing six cycles of chemotherapy. Although no statistical differences were detected in the total FLI-C scores or subscale scores between the study groups, we observed a rise in the total scores over the course of the study consistent with a chemotherapy-related effect (P < .0001, Fig 2). The physical, psychologic, social, and cancer hardship subscale scores all increased with time, but the nausea subscale score remained constant. Juniper et al¹⁷ have shown that the minimal important differences on questions with 7-point response options is half a scale point. Because the various FLI-C scales have different numbers of questions, this would translate into different amounts for each subscale. Differences of 4.5 points on the physical scale, three points on the psychologic scale, 1.5 points on the hardship scale, one point on each of the nausea and social scales, and 11 points on the total scale (provided all subscales differed in the same direction) would be considered clinically important. When the observed SDs and the useable sample size were used and a one-tailed test was assumed, the powers to detect these scale differences were 0.51, 0.63, 0.48, 0.61, 0.70, and 0.74, respectively. Had the sample size remained at 60 subjects per group, the powers to detect these differences would have been 0.56, 0.82, 0.54, 0.71, 0.79, and 0.83, respectively.

View larger version (16K): [in this window] [in a new window]   Fig 2. FLI-C total scores over six cycles of chemotherapy for the port () and control () groups. Although there was no allocation effect, there was a significant rise in total scores over the observation period (P < .0001).

Safety
There were six (8.3%) complications among the 74 patients who received a port in the course of this study, corresponding to a rate of 0.23 per 1,000 days of port use. No port-related infections were observed during this study. In three subjects, port implantation was complicated by pneumothorax. There was one episode each of thrombotic occlusion of the port, catheter fracture with migration, and erosion of the port through the overlying skin on the chest wall.

Costs
Table 3 details the costs in Canadian dollars associated with venous accessing, including port implantation, access equipment, and costs of performing the access procedures, both peripheral and port, in this study. Overall, the average per patient costs of venous accessing were higher in study patients compared with controls ($2,178 ± $271 v $530 ± $894, respectively; P < .0001). The average per patient costs of venous accessing for port recipients were similar regardless of allocation ($2,178 ± $271 v $2,193 ± $361 for study subjects and control subjects who received a port after cross-over, respectively; P = .87). The average per patient costs for peripheral venous access in the 44 controls who did not require central venous access was only $80.92.

	DISCUSSION

TOP ABSTRACT INTRODUCTION PATIENTS AND METHODS RESULTS DISCUSSION REFERENCES

 
Clinical trials to evaluate the safety and efficacy of these devices have been primarily open, single-arm, phase II studies^3,8,15,18-21 or comparative studies with externalized indwelling central venous catheter systems that used nonrandomized^7,9,10,13,22 or randomized^11,12,23 trial designs. This report is the first randomized, controlled clinical trial comparing the use of totally implantable venous access port systems implanted before chemotherapy and standard peripheral venous access.

Our study design allowed control subjects to cross over to receive central venous access if peripheral venous access could not be reliably achieved and maintained, thus providing an accurate estimate of the need for central venous access. Over one quarter (27%) of controls failed peripheral venous access and required a central venous access device to complete treatment. The majority of failures occurred within 3 months of the start of chemotherapy (median, 26 days).

The overall safety of port systems was demonstrated by the low complication rate observed in this study (0.23/1,000 port-use days) compared with the published range of 0.23 to 4.6/1,000 days.^{9,10,15,18-23} The absence of port-related infections observed in our study may have been due, in part, to the relative infrequency of prolonged myelosuppression and to the restriction of access to a limited number of skilled nurses. As in other studies, catheter fracture, occlusion, and reservoir erosion through the overlying skin were observed. Only one catheter failed because of thrombotic occlusion. Monthly heparinization proved to be a convenient and effective method of maintaining catheter patency. The 3.4% port failure rate was consistent with the average reported failure rate of 10% (range, 1% to 24%).^7,9,10-13,22

The study design also permitted a cost comparison of two strategies of port use, namely, "prophylactic" implantation before a planned course of chemotherapy and implantation on the basis of defined need. As noted previously, the latter approach was applied to the control population at one quarter the cost, overall (Table 3). We estimate that the prophylactic strategy would have to be applied to four patients in order to prevent one peripheral access failure, on the basis of the proportion of controls who failed peripheral access. The average costs of all venous accesses in control patients who did not require central venous access were 26 times less than for accesses in the port group. Benefits of the prophylactic strategy included reduced peripheral venous access–related pain and anxiety and some procedure-related cost advantages associated with less time-consuming peripheral accesses. Our observations suggest that use of the port for the administration of chemotherapy may have preserved venous integrity by reducing local venous trauma caused by repetitive cannulation and exposure to venotoxic agents. Knowledge that the port was available if peripheral access failed may also have contributed to the decreased incidence of anxiety among port recipients.

The ports in this study, as in the study of Mirro et al,¹³ were recommended for all venous accesses. In practice, however, study patients received the majority (61%) of their venous accesses for blood testing by peripheral phlebotomy or fingerprick. This may have introduced a systematic negative bias obscuring the potential quality-of-life benefit accruable through port use. Ports were used primarily for the administration of cytotoxic chemotherapy and other intravenous products. Although there were personnel trained in port access on the inpatient and outpatient cancer services, it was frequently more convenient to use peripheral access. Similarly, venous access procedures during off hours often required the services of health care providers who were less familiar with central venous accessing and tended to use peripheral rather than port accessing.

Quality-of-life studies were performed to examine whether port use could influence functional quality of life as reflected in the FLI-C total or factor subscores. Although port use reduced venous access trauma and discomfort, we found no measurable improvement in quality of life attributable to ports.

There were a number of limitations to this study. First, there was an uneven distribution of diagnoses between the study groups, despite the stratification and randomization procedures (Table 1), that may have resulted in an imbalance of factors, such as the choice of cytotoxic regimen, that could affect quality-of-life measurements and the frequency of venous accesses. Consequently, the generalizability of our results may be limited. Despite this, the observed differences did not reach statistical significance. Second, we failed to control for the effect of the port implantation procedure on quality-of-life and pain measurements in the port group. This bias could have been avoided by implanting ports into all patients followed by randomization to port or peripheral accessing. For ethical reasons, such a design was not believed to be justified. Despite this, the baseline quality-of-life measurements were similar for both groups (Fig 2). Third, serial quality-of-life data over six cycles of chemotherapy were available for analysis from only 92 subjects. Accordingly, our study sample size had limited power to detect clinically important quality-of-life differences derived from each of the subscale scores individually. This trial was designed before the availability of estimates for quality-of-life score differences from which sample sizes could be estimated.¹⁷ Despite this, powers of 0.83 and 0.74 for differences in total scores were observed for our original and assessable sample sizes, respectively, which suggests that our trial design was sufficiently robust to detect clinically important differences. Further, the repeated-measures analysis of variance applied in this analysis was a more powerful test of group differences than the single-point comparison upon which the power analysis was based. Last, our study underestimated the costs associated with port use because we omitted the costs associated with port-related complications. This omission would reduce the magnitude of the differences observed in the cost analysis but not the overall direction of those differences. Our study was not intended to prove that ports were more expensive than peripheral accessing, but rather to estimate the costs associated with port use in light of the other outcomes we studied, such as pain and discomfort.

During these times of economic restraint and limited health care resources, our findings have important implications for health care planners trying to rationalize the few health care dollars for the supportive care of increasing numbers of cancer patients requiring chemotherapy. This study has shown that totally implantable port systems are a safe, effective strategy for venous access in cancer patients. Although port use was associated with a reduction in peripheral access-related anxiety, pain, and discomfort, it is not clear whether these benefits outweigh the overall costs. Our results suggest that only a subgroup of patients identified by the criteria defined herein as failing peripheral accesses may accrue the most benefit from these devices. We would suggest these criteria could be used as a basis for deciding who would be best served by having an implantable port. In the Canadian universal health care system, in which health care dollars are scarce, it seems prudent to reserve the use of implantable port systems for patients who satisfy criteria mutually agreed upon by the health care providers and the funding agencies.

	ACKNOWLEDGMENTS

 
Supported by the St Boniface General Hospital Research Foundation and Pharmacia, Canada, Ltd

We are indebted to Drs R. Lotoki, G. Krepart, M. Heywood, and T. Shore for allowing us to study their patients; to A. Meekison, B. Scott, S. Genik, B. Lucko, and the Departments of Nursing of the Manitoba Cancer Treatment and Research Foundation, St Boniface General Hospital, and the Health Sciences Centre, who contributed greatly to the initial planning and subsequent conduct of this study; to B. Coss for her help with the manuscript; to Barbara Freed for her meticulous coordination of the data management; to Catherine Njui for her assistance with the quality-of-life analysis; and to Dr H. Schipper for his guidance with the quality-of-life assessment.

	REFERENCES

TOP ABSTRACT INTRODUCTION PATIENTS AND METHODS RESULTS DISCUSSION REFERENCES

 
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6. Groeger JS, Lucas AB, Thaler HT, et al: Infectious morbidity associated with long-term use of venous access devices in patients with cancer. Ann Intern Med 119:1168-1174, 1993[Abstract/Free Full Text]

7. Ingram J, Weitzman S, Greenberg M, et al: Complications of indwelling venous access lines in the pediatric hematology patient: A prospective comparison of external catheters and subcutaneous ports. Am J Pediatr Hematol Oncol 13:130-136, 1991[Medline]

8. Becton DL, Kletzel M, Gollady ES, et al: An experience with an implanted port system in 66 children with cancer. Cancer 61:376-378, 1988[Medline]

9. Stanislav G, Fitzgibbons RJ Jr, Bailey RT, et al: Reliability of implantable central venous access devices in patients with cancer. Arch Surg 122:1280-1283, 1987[Abstract/Free Full Text]

10. Greene FL, Moore W, Strickland G, et al: Comparison of a totally implantable access device for chemotherapy (Port-a-Cath) and long-term percutaneous catheterization (Broviac). South Med J 81:580-583, 1988[Medline]

11. Carde P, Cosset-Delaigue MF, LaPlanche A, et al: Classical external indwelling central venous catheter versus totally implanted venous access systems for chemotherapy administration: A randomized trial in 100 patients with solid tumours. Eur J Clin Oncol 25:939-944, 1989

12. Kappers-Klunne MC, Degener JE, Stijnen T, et al: Complications from long-term indwelling central venous catheters in hematologic patients with special reference to infection. Cancer 64:1747-1752, 1989[Medline]

13. Mirro J Jr, Rao BN, Stokes DC, et al: A prospective study of Hickman/Broviac catheters and implantable ports in pediatric oncology patients. J Clin Oncol 7:214-222, 1998[Abstract]

14. Clinch JJ: The Functional Living Index–Cancer: Ten years later, Spilker B (ed):Quality of Life and Pharmacoeconomics in Clinical Trials (ed 2)215-225Philadelphia, PA, Lippincott-Raven, 1996

15. Strum S, McDermed J, Korn A, et al: Improved methods for venous access: The Port-a-Cath, a totally implanted catheter system. J Clin Oncol 4:596-603, 1986[Abstract/Free Full Text]

16. Kaplan ER, Meier R: Non-parametric estimation from incomplete observations. J Am Stat Assoc 53:457-481, 1958

17. Juniper EF, Guyatt GH, Willan A, et al: Determining a minimal important change in a disease-specific quality of life questionnaire. J Clin Epidemiol 47:81-87, 1994[Medline]

18. Lokich JJ, Bothe A Jr, Benotti P, et al: Complications and management of implanted venous access catheters. J Clin Oncol 3:710-717, 1985[Abstract]

19. Brincker H, Saeter G: Fifty-five patient years' experience with a totally implanted system for intravenous chemotherapy. Cancer 57:1124-1129, 1986[Medline]

20. Brothers TE, Von Moll LK, Neiderhuber JE, et al: Experience with subcutaneous infusion ports in three hundred patients. Surg Gynecol Obstet 166:295-301, 1988[Medline]

21. Harvey WH, Pick TE, Solenberger RI: A prospective evaluation of the Port-a-Cath implantable venous access system in chronically ill adults and children. Surg Gynecol Obstet 169:495-500, 1989[Medline]

22. Guenier C, Ferreira J, Pector JC: Prolonged venous access in cancer patients. Eur J Surg Oncol 15:553-555, 1989[Medline]

23. Mueller BU, Skelton J, Callender DPE, et al: A prospective randomized trial comparing the infectious and non-infectious complications of an externalized catheter versus a subcutaneously implanted device in cancer patients. J Clin Oncol 10:1943-1948, 1992[Abstract]

Submitted July 7, 1998; accepted December 3, 1998.

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