Lemuel Herrera-Ornelas

Polyamine biosynthetic activity in normal and neoplastic human colorectal tissues

Polyamine biosynthetic activity was assessed in various colorectal tissue samples consisting of noninvolved mucosa, benign adenomatous polyps and adenocarcinomas taken at surgery from a total of 40 patients. Ornithine decarboxylase (ODC) displayed a gradient of enzyme activity (i.e., adenocarcinoma > polyps > mucosa) which seemed to correlate positively with the neoplastic status of the tissue. In 10 of the patients, samples were obtained for all three tissue types. Five of these exhibited a clear repetition of the trends in enzyme activity seen with the mixed patient tissue sampling whereas the remainder differed by having the highest ODC activity in the polyps. In nine of the ten cases, ODC activity was substantially lower in the mucosa than in either of the neoplastic lesions. Trends in enzyme activity were the same for tissues obtained from either the colon or rectum. The ODC activity in adenocarcinomas could not be correlated with histologic differentiation, stage or site of the disease, however, in samples from female patients (all postmenopausal) the activity was elevated over normal mucosa to a greater extent (ten‐fold) than in male patients (seven‐fold). S‐adenosylmethionine decarboxylase activity was assessed in 27 of the 40 patients and found to follow the same distribution as ODC; however, the mean value differences ± SEM between tissues were less distinct. In general, tissue polyamine pool analysis of these same specimens reflected the levels of ornithine and S‐adenosylmethionine decarboxylase activities. Overall, the data reveal an increase in polyamine biosynthetic activity in colorectal neoplasms, relative to surrounding mucosa, which may correlate with (1) progression of the neoplastic process, (2) the proportion of proliferating cells, (3) the rate of cell proliferation, or (4) a combination of two or all of these possibilities.

Photodynamic therapy in patients with colorectal cancer

A pilot study was conducted, in which photodynamic therapy (PDT), a technique in which malignant cells are destroyed by light after being previously photosensitized by a chemical compound, was tried in a group of 14 patients with recurrent or residual colorectal cancer in the pelvis. Three of the six patients with unresectable pelvic recurrences experienced a significant relief of pain after PDT. In two of the five patients who had an incomplete resection of their pelvic recurrences, there was also a substantial relief of pelvic pain after surgery and PDT. In one of these patients subsequent biopsies proved the disappearance of the residual pelvic microscopic disease after several sessions of PDT. Three patients had a recurrence from a squamous cell carcinoma primary of the anal canal. All recurrences were amenable to surgical resection. In one of the patients, PDT was used in an attempt to sterilize an area of residual tumor that was located over the left ischial tuberosity. The patient experienced good relief of pain, but died of her disease 7 months after PDT. In the other two patients, PDT was used as an „adjunct”︁ after resection of their recurrences. One of these patients was free of disease and died of an unrelated cause 12 months after PDT. The other is alive and well. This study demonstrated that PDT can be safe and tolerable in patients with pelvic malignancies. PDT is capable of tumor destruction, can be used repeatedly in areas previously exposed to ionizing radiation, and may have a role in the prevention and management of pelvic‐perineal recurrences from colorectal cancer.

A comparison of the 25-cm rigid proctosigmoidoscope with the 65-cm flexible endoscope in the screening of patients for colorectal carcinoma.

A comparison of the rigid with the flexible sigmoidoscope was evaluated in 293 patients as part of a screening project for colorectal cancer at Roswell Park Memorial Institute. Patients with either a positive family history for colorectal cancer, a positive stool guaiac test result, a history of hematochezia, or a change in bowel habits were randomly assigned to either rigid or flexible sigmoidoscopy. The median distance of colon examined with the flexible instrument was significantly greater than with the rigid scope (55 versus 17 cm, respectively). A significantly greater number of malignant and premalignant lesions were found with the flexible instrument than with the rigid scope. It was concluded that the flexible sigmoidoscope is superior to the rigid scope in the process of screening for colorectal lesions.

Results of synchronous surgical removal of primary colorectal adenocarcinoma and ovarian metastases.

Ovarian metastases from colorectal carcinoma are seldom isolated, frequently of a large size and bilateral; and a signal for a poor prognosis for survival. This report analyzes the clinical course of patients in whom ovarian involvement was recognized and treated at the time of surgery for their primary carcinoma.

Adenocarcinoma of the colon masquerading as primary ovarian neoplasia

This paper reviews the clinical characteristics of a group of patients in whom unsuspected primary adenocarcinoma of the colon presented with signs and symptoms of a primary ovarian neoplasia. In most patients the ovaries were removed, the correct diagnosis was established at a later time, and a second surgery for resection of the primary adenocarcinoma of the colon was then performed. Preoperative use of colonoscopy or barium-enema examination would have helped. We compared these patients to a group of patients with similar clinical characteristics, but in whom the ovarian metastases were clinically apparent months after the resection of a primary colorectal cancer. We found that, in both groups, age of the patients, anatomic distribution of the primary tumor, histologic differentiation, serosal or mesenteric lymph node tumor involvement, and timing of the oophorectomy in relationship to removal of the primary colorectal tumor did not affect the overall survival. Once ovarian metastases were documented, patients died regardless of treatment, approximately 16 1/2 months after the diagnosis.

Subcutaneous metastases without visceral metastases from an adenocarcinoma of the rectum

Skin metastasis from colorectal carcinoma without evidence of visceral metastases is exceedingly rare. However, it must be considered when-ever a new skin growth appears in a patient with a history of carcinoma. A diagnostic biopsy is mandatory as the appearance of these metastases is not distinctive.

Phase-I clinical trial of sodium cyanate in patients with advanced colorectal carcinoma.

Sodium cyanate, a drug that selectively suppresses amino acid incorporation for protein synthesis in tumor tissue, was given to patients with advanced colorectal carcinoma who had failed to conventional therapy, with the purpose of assessing a maximum tolerable oral dose. At 35 mg/kg p.o. daily, the drug had to be stopped in approximately half (4) of the patients because of gastrointestinal toxicity (nausea, vomiting) and neurologic toxicity (hallucinations, disorientation). However, in 5 other patients, at the same dose, the drug was well tolerated for up to 147 days and for a total cumulative dose of 308 g. In this group of patients, sodium cyanate was stopped because of evidence of tumor progression. No hematologic toxicity was observed. We observed no therapeutic effects. We therefore recommend a starting dose of 30 mg/kg p.o. if a phase-II study is considered.