The natural history of small renal masses

PURPOSE

Ultrasound, computerized tomography and magnetic resonance imaging are widely available. Incidentally discovered small renal masses are reported more frequently. Most of these masses are low stage renal cell carcinomas. To understand better the natural history of these lesions and offer appropriate management, we followed prospectively a series of patients with this type of lesion.

MATERIALS AND METHODS

A total of 13 patients with radiologically detected solitary small renal masses who were unfit for or refused surgery were followed with abdominal imaging for a median of 42 months. Median patient age was 69 years and mean lesion volume at diagnosis was 13.6 cm.3 or 2.95 cm. in diameter. Growth rate was calculated based on tumor volume rather than bi-dimensional diameter. Individual slopes of tumor size in time were calculated.

RESULTS

Of the 13 patients 5 underwent surgery following a period of surveillance because of apparent tumor enlargement or new onset of symptoms. Pathological evaluation revealed renal cell carcinoma in all 5. No patient had metastases. Only 2 tumors were fast growing and these were the only 2 cases in which symptoms developed. When these patients were excluded from analysis, average growth rate was 1.32 cm.3 per year (p = 0.5, 95% confidence interval -3.00 to 5.76 cm.3 per year), which was not statistically significantly different from 0 slope or no growth.

CONCLUSIONS

These results demonstrate that the growth rate of small renal tumors is variable, tumors that are destined to grow and possibly metastasize do so early and most small tumors grow at a low rate or not at all.

Factors influencing long-term primary cadaveric kidney transplantation--importance of functional renal mass versus avoidance of acute rejections--the Toronto Hospital experience 1985-1997

1. The 5-year actuarial graft, patient and functional graft survival rates were analyzed in 743 consecutive primary cadaveric kidney transplants from The Toronto Hospital between January 1985-December 1997. 2. Recipient age > or = 55 years, male recipient sex, recipient diabetes mellitus, CIT > 36 hours and delayed graft function were found to significantly decrease patient survival. 3. Recipient age > or = 55 years, sensitization to HLA antigens (peak PRA > 50%), donor/recipient HLA antigen mismatches, CIT > 36 hours, delayed graft, function and 6-month SCr > 200 mumol/L were found to significantly decrease graft survival. 4. Acute rejection episodes had no significant impact on overall 5-year patient or graft survival. 5. The observation that serum creatinine > 200 mumol/L had a major adverse influence on long-term outcome reflects the importance of functional renal mass on graft survival.

An analysis of predictors of long-term cadaveric renal allograft survival

To determine factors predictive of long-term graft function in patients treated prophylactically with an antilymphocyte antibody, 670 first cadaveric adult renal transplant procedures performed between 1985 and 1991 were reviewed. The actuarial 1- and 5-year patient survival in this group was 95% and 87% respectively, and graft survival was 84% and 70% respectively. The final analysis was based on a study group of 635 patients which excluded 28 patients who lost grafts to early technical failures and 8 patients who were not induced with an antilymphocyte preparation. Multivariate analysis showed that 5-year graft survival was lower in patients with delayed graft function (p = 0.0001), in those who had an acute rejection episode in the first 6 months post-transplant (p = 0.0001), recipients greater than 55 years of age at the time of transplant (p = 0.0001), in patients who were highly sensitized at the time of transplant (p = 0.0331) and, finally, in those who received a graft from an older donor (p = 0.044). The 209 patients with delayed graft function had a 16% lower long-term graft survival than 425 patients with early graft function (62% vs. 78% respectively at 5 years). One or more rejection episodes in the first 6 months post-transplant (329 patients) reduced long-term graft survival by 13% compared to those who did not have a rejection episode (67% vs. 80% respectively at 5 years).(ABSTRACT TRUNCATED AT 250 WORDS)

Possible association of donor blood group A with higher alloantibody responses after renal transplantation

Donor-specific alloantibody responses were studied in 55 patients receiving their first cadaver kidney transplant, using 51Cr release assays for complement-dependent cytotoxicity and antibody-dependent cell-mediated cytotoxicity against two types of donor targets: fibroblasts and lymphoid cells. When patients with pretransplant donor-specific antibody were excluded, the alloantibody responses were significantly more frequent in recipients of blood group A kidneys than in recipients of non-A (P = .004). The association was seen with both lymphocyte and fibroblast target cells, but was stronger when fibroblast targets were used. The association could not be explained adequately by differences in transfusion status or in graft survival between the A and non-A groups. The results suggest that certain types of alloantibody response against the graft are more vigorous in recipients of group A kidneys than in other recipients. Such responses may contribute to the tendency of group A patients to show poorer graft survival in some studies.

Autoantibody against fibroblasts in renal transplant recipients: analysis by 51Cr-release assays

In testing for donor-specific alloantibody in renal transplantation we discovered that sera of many recipients lysed their own fibroblasts in complement-dependent cytotoxicity. The incidence of this autoreactivity before and during the first month post-transplant was 15 and 10% respectively, but rose to 48% after 2 months. There was a significant association between autoantibody formation and the presence of donor-specific alloantibody, but no association between autoantibody and graft survival. Autoantibody reactive with fibroblasts was three times more frequent than lymphocytotoxic autoantibody, and showed no association with the presence of such antibody, indicating that these autoantibodies were directed against different antigens. Reduction with 2-mercaptoethanol indicated that much of the autoreactivity was IgM. By absorption tests the autoantigen was shown to be expressed extensively on fibroblasts, but not on lymphocytes, platelets or red cells. Susceptibility to lysis by the autoantibody varied from day to day in the fibroblasts of a particular individual, and also varied from individual to individual. These results are of interest because they indicate that autoantibody formation in human renal allografts may result from chronic allogeneic stimulation, and that the antibody may be detecting a previously unknown fibroblast antigen.

Detection of antidonor antibody: advantages of fibroblast target cells

Donor specific alloantibody was monitored in 40 kidney transplants for 3 most post-transplant. Two 51Cr release assays were used: complement-dependent lysis and antibody-dependent cell-mediated cytotoxicity. Fibroblast, lymphocyte, and lymphoblast target cells were all tested whenever possible. Antibody was detected in only 6 of 22 patients who achieved satisfactory function (creatinine less than 3 at 3 mos), but in 15 of 18 patients who had an unfavorable outcome (return to dialysis or creatinine greater than 3 at 3 mos). The association of antifibroblast antibody with poor function was particularly striking: in the 33 patients in whom donor fibroblasts were tested, none of 20 with good function had detectable antibody, whereas 10 of 16 with graft loss or poor function had detectable antibody. Studies with mouse fibroblasts indicated that the association of antifibroblast antibody with graft destruction may be explainable in terms of selective expression of various alloantigens on fibroblasts.

Ankylosing spondylitis and the major histocompatibility system

The purpose of this investigation was to see whether or not the hypothetical disease susceptibility locus to ankylosing spondylitis is linked to the MLC determinant 27a. Firstly, we discovered a strong MLC determinant which we called 27a because of its association with the second series specificity W27. Later, we found that this determinant was the same as that which Jorgensen et al. (1973) found to be associated with the second series specificity W5. These MLC determinants may, therefore, be in linkage disequilibrium with more than one HL-A specificity (in this case, of the second series) as previously described by Dupont et al. (1973). However, we found no association between 27a and ankylosing spondylitis. On the other hand, we confirmed the association of ankylosing spondylitis with W27 and also found an increase of HL-A2 of the first series which, however, was not statistically significant. In view of the high incidence of HL-A2 in the general population, more information is required to definitely establish such an association. We found no special association with specificities AJ and Hu (Sa 532), third series antigens, but confirmed their linkage disequilibrium with W27. Disease predisposition loci seem, therefore, to be associated with either type of MHS marker, multiple sclerosis and MLC determinant 7a, or ankylosing spondylitis and the second series antigen W27. It will be interesting to discover whether there is any special significance of the association of one marker rather than another.