Biomedical subjects

Ramesh Rengan

Publications and source records attributed to Ramesh Rengan.

4 recordsLinked to original sources

PubMed2006

Ten-year results of preoperative radiation followed by sphincter preservation for rectal cancer: increased local failure rate in nonresponders.

BACKGROUND: The primary objective of this study was to determine the long-term outcome of sphincter preservation with preoperative radiation therapy (RT) and surgical resection in the treatment of distal rectal adenocarcinoma. PATIENTS AND METHODS: Between April 1988 and December 1996, 36 (cT2, n=9; cT3, n=27) patients with rectal adenocarcinoma were enrolled on a phase I/II trial of preoperative RT followed by surgical resection. All patients had distal tumors that were clinically judged to require an abdominoperineal resection and received preoperative RT (50.4 Gy) followed by surgery. The median follow-up was 94.5 months (range, 4-187 months). RESULTS: Of the 35 patients in this study who underwent resection, 77% were able to undergo sphincter preservation after preoperative RT. The pathologic complete response rate for these patients was 14%. The 10-year rates of overall survival and local failure for patients undergoing sphincter preservation were 54% and 21%, respectively. The 10-year local failure was 26% in patients with cT3 disease who underwent sphincter preservation. All local failures in this study occurred in patients with cT3 disease undergoing sphincter preservation; however, none of the patients with cT3 disease that was downstaged by preoperative RT experienced local failure. In contrast, 10-year local failure was 67% in the patients with cT3 disease that was not downstaged by RT. Sphincter function was good or excellent in 85% of patients at the time of last follow-up. CONCLUSION: This approach provides excellent long-term results in all patients with cT2 disease and those with cT3 disease that is downstaged by RT. However, patients with cT3 disease that is not downstaged by RT have an increased risk of local failure. These data underscore the impact of tumor response to radiation on long-term oncologic outcome.

Adenocarcinoma↗

PubMed2005

Distal cT2N0 rectal cancer: is there an alternative to abdominoperineal resection?

PURPOSE: Patients with cT2N0 distal rectal cancer do not require adjuvant therapy. However, when a patient refuses an abdominoperineal resection (APR), is there an alternative? The purpose of this trial is to determine whether preoperative external-beam radiation therapy can increase the rate of sphincter preservation for patients with distal cT2N0 adenocarcinoma of the rectum. PATIENTS AND METHODS: Between April 1988 and October 2003, 27 patients with distal rectal adenocarcinoma staged T2 by clinical and/or endorectal ultrasound who were judged by the operating surgeon to require an APR were treated with preoperative pelvic radiation alone (50.4 Gy). Surgery was performed 4 to 7 weeks later. If pathologic positive pelvic nodes were identified, postoperative adjuvant chemotherapy was recommended. The median follow-up was 55 months (range, 9 to 140 months). RESULTS: The pathologic complete response rate was 15% and 78% of patients underwent a sphincter-sparing procedure. The crude incidence of local failure for patients undergoing a sphincter sparing procedure was 10% and the 5-year actuarial incidence was 13%. The actuarial 5-year survival for patients undergoing sphincter preservation was as follows: disease-free, 77%; colostomy-free, 100%; and overall, 85%. Using the Memorial Sloan-Kettering Cancer Center sphincter function score, 54% of those undergoing a sphincter-sparing procedure had good/excellent bowel function at 12 to 24 months after surgery, and 77% had good/excellent function at 24 to 36 months after surgery. CONCLUSION: Our data suggest that for patients with cT2N0 distal rectal cancer who require an APR, preoperative pelvic radiation improves sphincter preservation without an apparent compromise in local control or survival.

Adenocarcinoma↗

PubMed2005

Does registration of PET and planning CT images decrease interobserver and intraobserver variation in delineating tumor volumes for non-small-cell lung cancer?

PURPOSE: To compare tumor volume delineation using registered positron emission tomography (PET)/CT vs. side-by-side image sets. METHODS AND MATERIALS: A total of 19 patients with non-small-cell lung cancer had 18-fluorine-deoxyglucose (FDG)-PET scans registered with planning CT scans. The disease was Stage I-II in 26%, IIIA in 42%, and IIIB in 32%. Two radiation oncologists contoured 9 tumor volumes using registered images (registered) and 10 using separate FDG-PET images as a guide (nonregistered). A third physician, who had done the treatment planning for these patients a median of 40 months before using registered images, repeated all contours: 10 on registered images (registered/registered) and 9 without registration (registered/nonregistered). Each pair of volumes (A and B) was compared. Quantitative comparison used the concordance index, (A intersection B)/(A union or logical sum B). For qualitative analysis, pairs of volumes were projected onto digitally reconstructed radiographs. The differences were graded as insignificant, minor, moderate, or major. RESULTS: The median interobserver percentage of concordance among nonregistered pairs was 61% vs. 70% in the registered group (p <0.05). On qualitative analysis, in the nonregistered group, the differences were insignificant in 5, minor in 3, and moderate in 2 of 10. The differences in the registered group were insignificant in 7 and minor in 2 of 9. The median intraobserver percentage of concordance in the registered/nonregistered group was 58% vs. 71% in the registered/registered group (p = 0.10). On qualitative analysis, the intraobserver differences in the registered/nonregistered group were insignificant in 2, minor in 2, moderate in 0, and major in 5 of 9. In the registered/registered group, the differences were insignificant in 2, minor in 6, moderate in 2, and major in 0 of 10. CONCLUSION: Registration of FDG-PET and planning CT images results in greater consistency in tumor volume delineation.

Adult↗

PubMed2004

Improved local control with higher doses of radiation in large-volume stage III non-small-cell lung cancer.

PURPOSE: It has been suggested that larger tumor volume is associated with poor survival in patients with non-small-cell lung cancer (NSCLC). We investigated whether high-dose radiation improved local control in patients with large-volume Stage III NSCLC. METHODS AND MATERIALS: Seventy-two patients with Stage III NSCLC and gross tumor volumes (GTV) of greater than 100 cc were treated with three-dimensional conformal radiotherapy (3D-CRT). Patients were divided into two groups: those treated to less than 64 Gy (37 patients) and those treated to 64 Gy or higher (35 patients). RESULTS: The 1-year and 2-year local failure rates were 27% and 47%, respectively, for Stage III patients treated to 64 Gy or higher, and 61% and 76%, respectively, for those treated to less than 64 Gy (p = 0.024). The median survival time for patients treated to 64 Gy or higher was 20 months vs. 15 months for those treated to less than 64 Gy (p = 0.068). Multivariate analysis revealed that dose and GTV are predictors of local failure-free survival. A 10 Gy increase in dose resulted in a 36.4% decreased risk of local failure. CONCLUSIONS: Our data suggest that administration of higher doses using 3D-CRT improves local control in Stage III NSCLC patients with large GTVs.

Adult↗