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I Alvarado

Publications and source records attributed to I Alvarado.

13 recordsLinked to original sources

Specific c-K-ras gene mutations as a tumor-response marker in locally advanced rectal cancer treated with preoperative chemoradiotherapy.

BACKGROUND: Forty percent of patients with colorectal cancer develop mutations in the K-ras gene. OBJECTIVE: Our objective was to evaluate whether the presence of c-K-ras gene mutations is a useful tumor-response marker in patients with locally advanced rectal cancer treated with preoperative chemoradiotherapy. MATERIAL AND METHODS: Thirty seven patients with locally advanced rectal cancer were treated with preoperative chemoradiotherapy. Four to six weeks later, surgery was performed. Specimens were classified according to the UICC-AJC classification. A segment of the tumor was obtained to analyze specific c-K-ras gene mutations. Restriction fragment length polymorphism (RFLP) and single strand confirmation polymorphism (SSCP) techniques were used with a set of probes to detect specific c-K-ras mutations in codons 12, 13, and 61. The 37 patients were divided into Group A (with mutations) and Group B (without mutations). RESULTS: All 37 patients completed the scheduled treatment. Group A consisted of 12 patients, whose tumors were classified and specific c-K-ras mutations were located as follows: eight in codon 12, two in codon 13, and one in codon 61. Group B consisted of 25 patients. The tumors were classified and there were more early-stage tumors in Group A, whereas in Group B there were more advanced-stage tumors (P = .05, respectively). The mean follow-up was 36.2+/-18.3 months. All Group A patients survived, whereas 8 of the 25 patients in Group B died due to progressive metastatic disease. Survival in Group A was 100%, whereas in Group B it was 59% (P = .03). CONCLUSIONS: The presence of specific c-K-ras mutations is an indicator of tumor response in patients with locally advanced rectal cancer treated with preoperative chemoradiotherapy and surgery. Therefore, responding patients may be more amenable to less radical surgical procedures based on c-K-ras mutations.

Adenocarcinoma↗

Second lethal events associated with treatment for Hodgkin's disease: a review of 2980 patients treated in a single Mexican institute.

Presence of second neoplasms and cardiac toxicity has been recognized as potential late lethal second events in patients treated for Hodgkin's disease. However, most reports analyze these association independently. We reviewed 2980 cases of patients treated during 1970-1995 with long-term follow-up (> 4 years) in an attempt to identify all late events in Hodgkin's disease secondary to the treatment or those which are unrelated. Three hundred and ten patients died, and of these 156 were secondary to relapse and tumor progression. Death associated second tumors and cardiac events were increased 37 fold and 29 fold respectively compared to the general population. The risk factors for this complications did not differ to previous reports and included alkylating agents and/or radiotherapy for second neoplasms and anthracycline therapy and radiotherapy for cardiac toxicity. Moreover, 61 patients died secondary to non-related events. Nevertheless, at 20-years overall survival was 90 % (95 % confidence interval (CI): 78 % to 97 %) and event free survival was 88 % (95 % CI: 76 % to 96 %) for these patients. Thus, second events, fatal in most cases, should be considered as an expected risk to the treatment in patients with Hodgkin's disease; the proposed modifications of therapy may indeed be useful to avoid or diminish these complications in the future.

Adult↗

Colorectal sarcoma: analysis of failure patterns.

BACKGROUND AND OBJECTIVES: Colorectal sarcomas (CRS) are rare and their treatment remains controversial, especially for those located in the rectum. The aim of this paper is to evaluate our experience, with special emphasis on the failure pattern after surgical therapy alone or combined with postoperative radiotherapy. MATERIALS AND METHODS: The medical records and histological slides of 13 CRS patients treated between 1986 and 1996 were reviewed retrospectively. RESULTS: The patients included eight males and five females, with a median age of 54 years; nine of their primary tumors were located in the rectum, and four in the colon. The histologies were leiomyosarcoma in nine cases and malignant fibrous histiocytoma in four cases. Surgical treatment consisted of anatomical colectomy (four); local excision (three); abdominoperineal resection (APR)(two); low anterior resection (LAR)(two); LAR en bloc with the prostate (one), and total pelvic exenteration (one). One operative death occurred. The median size of the tumors was 8 cm (range, 5-40). The tumors were graded as low, three, and high, ten. The median follow-up was 24 months. Eight patients in the overall group developed recurrences as follows: local, three; local and distant, three, and distant, two. Five out of nine patients with rectal sarcoma received adjuvant postoperative radiotherapy (PRT). Local recurrence occurred in 20% (1/5) of those who received PRT, and in 100% (3/3) of those who did not. The overall 5-year survival was 40%, and the 5-year survival for patients with low-grade tumors was 66%, as compared with 22% for those with high-grade tumors. CONCLUSIONS: The patterns of failure in CRS are combined in both local and distant sites. However, our results suggest that in rectal sarcoma, the use of surgery + PRT may reduce the local recurrence rate; in selected patients, it may allow for anal sphincter preservation.

Adult↗

Modified clearing technique to identify lymph node metastases in post-irradiated surgical specimens from rectal adenocarcinoma.

The aim of this study is to describe a modification of the original method of clearing lymph nodes in specimens from rectal adenocarcinoma and its yield in comparison to a control group whose specimens were studied by a manual technique. There were 32 consecutive patients with locally advanced rectal adenocarcinoma. All patients received preoperative radiation therapy (PRT) at doses of 45 Gy, concomitant with 5-fluorouracil at the doses of 450 mg/m2 IV bolus, days 1-5 and 28-33 of PRT; 4-8 weeks later radical surgery with a curative intent was performed. Twenty two specimens were studied by a manual technique consisting of fixation in 10% formalin. Ten specimens were studied with the modified clearing technique consisting of administration through the inferior mesenteric artery of methylene blue; fixation with 10% formalin plus 0.01% of methylene blue; clearing the fat with a sequence of 95% alcohol-100% acetone-100% xylene. In the 32 specimens, 413 lymph nodes were found. Using the manual technique 104 lymph nodes were found (average 4.7 lymph nodes per specimen); 309 lymph nodes by the modified clearing technique (average 30.9 lymph nodes per specimen), (p < 0.0001). Using the manual technique 23 out of 104 lymph nodes (22%) contained metastases. All metastatic lymph nodes measured > 5 mm; 18 out of 23 metastatic lymph nodes were located on the perirectal area (level 2); and five were located in the root of the inferior mesenteric artery (level 5). Using the modified clearing technique 278 out of 309 (89%) lymph nodes measured < 5 mm; 15 out of 309 (4.8%) lymph nodes contained metastases; 9 out of 15 (60%) measured > 5 mm and were located on levels 2 and 5; and six, located on level 5, measured < 5 mm. The modified clearing technique is a quick, easy and reproducible method for identifying lymph nodes in post-irradiated surgical specimens. In comparison to the traditional manual method of searching for lymph nodes, it improves in the detection of small lymph nodes (< 5 mm), allowing better staging in patients with rectal adenocarcinoma.

Adenocarcinoma↗

p53 protein overexpression and response to induction chemoradiation therapy in patients with locally advanced rectal adenocarcinoma.

BACKGROUND: The association between mutations in the p53 gene and prognosis in colorectal cancer remains controversial. This report evaluates the role of p53 protein to predict the response of neoadjuvant chemoradiation therapy in patients with primary locally advanced rectal adenocarcinoma. METHODS: Between January 1993 and December 1994, 26 patients were seen with locally advanced primary rectal adenocarcinoma, located between 0 and 10 cm from the anal verge, demonstrated clinically and by CT scan. Each received 45 Gy of preoperative radiation therapy (RT) concomitantly with bolus infusion of 5-fluorouracil (5-Fu) (450/mg/m2 on days 1 to 5 and 28 to 33 of RT). Surgery was performed between 4 and 8 weeks later. All the primary tumors were mapped and sliced. The response rate was divided according to the percentage of malignant cells in the rectal wall and perirectal fat. Lymph nodes were studied with the manual or modified clearing technique. p53 mutant status was assessed immunohistochemically from sections of the formalin-fixed, paraffin-embedded pretreatment biopsy and the resected specimen. RESULTS: There were 14 females and 12 males, with a mean age of 54 years. All received the scheduled treatment. An abdominoperineal resection (n = 10), low anterior resection (n = 10), and pelvic exenteration (n = 6) were performed. The stages of tumors were as follows: no residual tumor (n = 4); T2 (n = 6); T3-4 (N = 9); and T3-4, N1,2 (n = 7). Fourteen specimens (54%) had mutated p53, and 10 (71%) had >50% of residual tumor, whereas only two (17%) of the specimens with normal p53 had >50% of residual tumor (P = .018). Eight of the 10 low anterior resections were performed in patients whose specimens expressed normal p53. CONCLUSION: Our results suggest that the determination of p53 is a factor in predicting tumor response in patients who undergo preoperative chemoradiation therapy for rectal adenocarcinoma.

Adenocarcinoma↗

[Prevalence of Barrett's esophagus in patients with colorectal carcinoma].

OBJECTIVE: To determine Barrett's esophagus (BO) prevalence in patients diagnosed with colorectal carcinoma (CC) and feasibility-associated factors in a 10 week period from March 1st to June 15, 1999. PLACE: Endoscopy Department, Oncology Hospital, Centro Médico Nacional Siglo XXI, IMSS. METHOD: A prospective, transversal, observational and comparative assay of 48 patients with histologically confirmed diagnosis of colorectal carcinoma in whom high endoscopy with biopsy harvest was performed; otherwise, colonoscopy was performed in eight patients with confirmed BO. RESULTS: Thirty men and 18 women were studied with an average age of 53 years of age. In 100%, colon cancer was determined as adenocarcinoma and location were rectal in 43.7%. Prevalence of BO was 22.9% in addition to 0.74 to 2% in the general population. This implies an odds ratio calculated at 36.43 (p = 0.00000) and 3.09 p = 0.00007), respectively, for risk to present BO concomitant with CC. There was no statistical significance in relation to age, smoking habit, and/or alcoholism. Among eight patients with BO without CCR, only one had a tubulovellous polypus (12.5%) identified. CONCLUSIONS: Although the results were not to conclusive to affirm the association of BA with CCR, the high prevalence found justifies the performance of routine endoscopy in CCR carrier patients with reflux symptoms.

Adenocarcinoma↗

[The mechanisms of the dissemination and the treatment of ovarian metastases in colonic adenocarcinoma].

OBJECTIVE: The aims of this study are: 1) To known the frequency of ovarian metastasis, 2) to define the role of the surgical therapy and 3) to establish the mechanism of spread of colorectal cancer to the ovaries. MATERIAL AND METHODS: Between 1989 and 1993 624 patients with colorectal adenocarcinoma; were treated, 19 (7.7%) had ovarian metastasis; they were divided in 2 groups according to the diagnostic time: A) synchronous; B) metachronous. In most patients a peritoneal lavage were performed; the primary tumor was resected. RESULTS: The median age was 41.4 years. In group A: there were 9 patients; in 3 of them underwent elective surgery and in 6 an exploratory celiotomy due to colonic obstruction or perforation. The primary tumor was located in the sigmoid in 8 patients and in cecum in 1; the stage of the primary tumor was follows: B1, 2; B2, 3; C2, 4. The ovarian metastasis were located in the left ovary in 6; right, 2, and bilateral 1. The peritoneal lavage was positive in 6, and negative in 3. In group B: there were 10 patients; one underwent elective surgery and 9 exploratory celiotomy. The primary tumor was located in the sigmoid in 9, caecum in 1. The stage of the primary tumors were: B2, 4; C2 4; D, 2. The ovarian metastasis were located: left, 5; right, 1; bilateral, 4. The peritoneal lavage was positive in 6, negative in 2. The 5-year survival in group A was 16% in group B, 0%. CONCLUSION: Ovarian metastasis were associated with advanced metastatic diseases. The treatment of synchronous ovarian metastasis is the resection of primary tumor plus bilateral oophorectomy, and in metachronous metastasis it is palliative. The mechanism of spread to the ovaries is by direct implantation and hematogenous.

Adenocarcinoma↗