Historically, several retrospective series suggested a clinical benefit
to adjuvant radiation therapy for renal cell carcinoma. Two European studies were
undertaken to test the efficacy of preoperative radiation therapy in renal cell
cancer. A prospective randomized study of preoperative irradiation and nephrectomy versus
nephrectomy was conducted in Rotterdam. No advantage was demonstrated in patients
receiving radiation therapy with respect to overall survival or survival free of distant
metastasis. In Sweden, a second prospective randomized clinical trial was also unable to
demonstrate an advantage to patients receiving preoperative radiation therapy.
Postoperative radiation therapy was reported to be beneficial in early
retrospective studies. Two prospective randomized studies testing the value of
postoperative irradiation did not demonstrate an advantage to patients receiving radiation
therapy after surgery. The four prospective randomized trials that have studied the
effects of adjuvant radiation therapy seem to argue convincingly against its routine use
in patients with renal cell carcinoma. There are some circumstances in which radiation
therapy should be considered as part of the curative treatment for renal cell carcinoma.
Radiation therapy has increased the resectability of locally advanced tumors in both
prospective and retrospective series. The lack of benefit from postoperative irradiation
in the prospective clinical trials may be explained by poor patient selection and
radiation therapy technique. A retrospective review from Memorial Sloan-Kettering Cancer
Center of 172 patients treated by radical nephrectomy demonstrated an overall local
failure rate of only 5%. The majority of patients in this series had T1 or T2 tumors.
Patients with lymph node metastases or positive margins had a significantly higher local
failure rate of 21%, compared with 4% in patients without these bad prognostic features.
This suggests that if a benefit from postoperative irradiation exists, it would be
demonstrable only in patients with pathologic features that would increase their risk of
local failure. Early-stage tumors have an extremely good local control rate, and therefore
radiation therapy would not be expected to play a beneficial role in patients with these
tumors.
Kao and associates reported that, in a retrospective series, 12 patients with high-risk,
locally advanced tumors with perinephric invasion or surgically positive margins had a
100% local control rate if treated adjuvantly with postoperative irradiation. Patients
received 41.4 to 63 Gy in 1.8- to 2-Gy fractions. The 5-year local failure rate was 30% in
a comparable group of patients treated by surgery only during this same period Another
retrospective series demonstrated that 37 patients with T3 tumors had a statistically
significant lower local failure rate (10%) when given postoperative irradiation, compared
with 30 similar patients undergoing nephrectomy alone (37%). Patients received a
median dose of 46 Gy in 1.8- to 2-Gy fractions; CT-assisted treatment planning was used in
most patients. Recent retrospective series have suggested a benefit to postoperative
radiation therapy in patients selected because of a high risk of local recurrence.
Based on this collection of both prospective and retrospective
data, the following indications for adjuvant radiation therapy should be considered:
(1) unresectable nonmetastatic tumors (preoperative irradiation); (2) incomplete resection
with gross or microscopically positive margins; (3) locally advanced tumor with
perinephric fat extension or adrenal invasion (T3a or T3c) -- renal vein or inferior vena
cava involvement alone (T3b) does not necessarily increase the risk of local recurrence
and should not be considered an indication for radiation therapy; or (4) lymph node
metastases. Lymph node metastases are associated with both a high rate of distant
metastasis and local failure. Although radiation therapy may decrease the local recurrence
rate, an improvement in overall survival may not be demonstrated in this circumstance. Read some of the studies |
