Papers by Paul Williamson
Geophysical Prospecting, 1994
Differences between traveltimes from sonic to seismic frequencies, commonly known as drift, can b... more Differences between traveltimes from sonic to seismic frequencies, commonly known as drift, can be attributed to a combination of multiple scattering and absorption. The portion due to scattering can be estimated directly by calculating synthetic seismograms from sonic logs. A simple alternative approach is suggested by the long-wave equivalent averaging formulae for the effective elastic properties of a stack of thin layers, which gives the same traveltime delays as the lowfrequency limit of the scattering dispersion. We consider the application of these averaging formulae over a frequency-dependent window with the hope of extending their use to frequencies higher than those allowed by the original validity conditions. However, comparison of the time delay due to window-averaging with the scattering dispersion predicted by the O'Doherty-Anstey formula reveals that it is not possible to specify a form of window that will fit the dispersion across the spectrum for arbitrary log statistics. A window with a width proportional to the wavelength squared matches the behaviour at the low-frequency end of the dispersive range for most logs, and allows an almost exact match of the drift across the entire spectrum for exponential correlation functions. We examine a real log, taken from a hole in nearly plane-layered geology, which displays strong quasi-cyclical variations on one scale as well as more random, smaller-scale fluctuations. The details of its drift behaviour are studied using simple models of the gross features. The form of window which gave a good theoretical fit to the dispersion for an exponential log correlation function can only fit the computed drift at high or low frequencies, confirming that there are at least two significant scale-lengths of fluctuation. A better overall fit is obtained for a window whose width is proportional to the wavelength. The calculated scattering drift is significantly less than that observed from a vertical seismic profile, but the difference cannot be wholly ascribed to absorption. This is because the source frequency of the sonic tool is not appropriate for its resolution (receiver spacing) so that the scattering drift from sonic to seismic frequencies cannot be fully estimated from the layer model derived from the log.
Southern medical journal, 1992
We evaluated local recurrences of midrectal cancer in 33 patients treated with low anterior resec... more We evaluated local recurrences of midrectal cancer in 33 patients treated with low anterior resection and stapled end-to-end anastomosis. All patients had follow-up for at least 2 years or until death. There were 21 men and 12 women. Data were analyzed with attention to Astler-Coller modified Dukes' stage, distal margin of resection, degree of histologic differentiation, location of the tumor, blood transfusion, and adjuvant therapy. Distal margin of resection, histologic differentiation, and location of the tumor had no prognostic significance regarding local recurrence. The use of adjuvant therapy remains controversial. The immunosuppressive effects of blood transfusion may affect local recurrence. Dukes' staging remains the standard for prognosis of recurrence in rectal cancer.
Seminars in Colon and Rectal Surgery, 2003
Anorectal physiology testing provides the clinician with objective evidence of functional disorde... more Anorectal physiology testing provides the clinician with objective evidence of functional disorders. Standardization of tests and scoring system is desirable. This information is important to develop meaningful treatment algorithms. Anorectal manometry, electromyography, defecography, colon transit study, and anorectal ultrasound are utilized to delineate treatment strategies in patients with chronic constipation, rectocele, rectal prolapse, solitary rectal ulcer, chronic anal fissure, chronic anal pain, anismus, and fecal incontinence. Biofeedback therapy is helpful in many patients with functional disorders and should be available wherever anorectal physiology tests are performed. In addition, anorectal functional tests assist in the selection and management of patients who require low anal or rectal anastomosis and transanal and trans-sphincteric procedures. The future development of pelvic floor units will enhance the interspecialty cooperation between colon and rectal surgeons, urologists, and urogynecologists with great advantages for patients with functional pelvic disorders.
Surgical Endoscopy, 2010
This study aimed to develop a noninvasive orthotopic model for metastasis of colon and rectal can... more This study aimed to develop a noninvasive orthotopic model for metastasis of colon and rectal cancer using a transanal approach. Currently, the most accurate orthotopic representation of metastatic human colon cancer is via a cecal injection. The transanal model allows for further examination of systemic immune responses, tumor take, and onset of metastasis without prior surgical intervention. For this study, 60 Balb/c mice were anesthetized and subjected to gentle anal dilation using blunt-tipped forceps at the anal opening. Murine colon cancer parental CT26 or luciferase-labeled CT26 (CT26-luc) cells were injected submucosally into the distal posterior rectum (30 CT26 and 30 CT26 injections) at concentrations of 2.5 x 10(4), 1 x 10(5), and 1 x 10(6) in a volume of 50 microl. Tumor growth and metastatic development was monitored at 5-day intervals for 50 days. All the remaining mice were killed on postinjection day 50. The optimal concentration for metastasis and survival of the mice was 2.5 x 10(4) cells. Higher concentrations of cells yielded higher mortality but did not result in metastasis. The overall success of tumor growth in both experiments using the transanal rectal injection was 65%. Histology showed that all tumors were poorly differentiated adenocarcinomas. Two mice (3.3%) from the 2.5 x 10(4) CT26-luc group showed metastatic colonic adenocarcinoma to the liver on postinjection day 50. Transanal rectal injection of colon cancer cells offers a nonoperative orthotopic murine model for colon cancer that may lead to the development of metastasis. By using an orthotopic model, more aspects of metastatic colon cancer can be evaluated without the influence of a previous abdominal incision. These results warrant more investigation.
Southern Medical Journal, 1991
The Journal of Trauma: Injury, Infection, and Critical Care, 1993
Blunt pelviperineal trauma has been associated with mortality rates of 32% to 58% in recent liter... more Blunt pelviperineal trauma has been associated with mortality rates of 32% to 58% in recent literature. A review of our institution's experience revealed a much lower mortality rate, prompting further investigation. Nine hundred-seventy five patients with pelvic fractures were admitted to our institution from July 1984 through June 1991. The mortality rate for all pelvic fractures was 7.3%. During this interval 21 patients (2.2%) were admitted with open pelvic fractures. Only one patient in this group died. Our low mortality figures were the result of better control of pelvic hemorrhage and sepsis, and a lower incidence of associated injuries to the head and thorax, representing a more favorable mechanism of injury.
Journal of Gastrointestinal Surgery, 2013
Although the literature describes mutY homolog gene (MYH) polyposis as an autosomal recessive syn... more Although the literature describes mutY homolog gene (MYH) polyposis as an autosomal recessive syndrome, we report a case of colorectal cancer in a carrier of MYH polyposis. Biallelic mutations in the MYH gene have been shown to increase the risk of colorectal cancer over the lifetime of the mutation carrier.1,2 However, there is no clear consensus in the literature as whether a monoallelic mutation increases the risk for colorectal cancer.3 In this report, we postulate that a single mutation is sufficient to increase the risk of colorectal cancer. We also propose that the G382D MYH mutation may play a dominant rather than a recessive role in polyposis and cancer development.
Diseases of the Colon & Rectum, 2007
PURPOSE: In this article, we review the laparoscopic experience of general surgery and colorectal... more PURPOSE: In this article, we review the laparoscopic experience of general surgery and colorectal residency training programs in the United States during the past 5 and 12 years, respectively. The purpose of this study was to determine whether an adequate experience was being provided, and at what level of training, to safely and effectively perform advanced laparoscopy. METHODS: General Surgery Operative Reports from the training years 2000 to 2004 were obtained from the Accreditation Council for Graduate Medical Education. Similarly, colorectal operative performance logs from the training years 1994 to 2005 were obtained from the American Board of Colon and Rectal Surgery. RESULTS: From 2000 to 2004, basic and advanced laparoscopic cases (as designated by the Accreditation Council for Graduate Medical Education) have increased from 10.1 to 12.2 percent and 2.1 to 3.7 percent, respectively. Within this period, the number of laparoscopic colon cases/resident/career has increased from 1.8 to 4.6. The percentage of cases performed laparoscopically increased from 3.9 to 22.5 percent from 1993-1994 to 2004-2005 training years. From 1993 to 2001, the average number of laparoscopic cases/resident increased from 6.3 to 16.1. In 2004, the average number of cases/resident increased to 45.3. Of this number, 30 were colon, 9.4 were rectal, and the remaining 5.9 were miscellaneous colorectal procedures. CONCLUSIONS: Learning curves for laparoscopic colectomy are reported in the range of 20 to 60 cases. Based on the most recent data reviewed, colon and rectal resident experience is trending toward this threshold. Recent general surgery graduates may be lacking the appropriate volume to reach proficiency in laparoscopic colorectal surgery.
Diseases of the Colon & Rectum, 1999
Small-cell carcinoma of the rectum is an ingrequent pathologic finding, and its precise incidence... more Small-cell carcinoma of the rectum is an ingrequent pathologic finding, and its precise incidence is unknown. Its incidence is less than 0.2 percent among all colorectal cancers. This tumor manifests highly aggressive behavior. The treatment of choice is combination chemotherapy similar to that used for small-cell carcinoma of the lung, but in small localized tumors surgery plus chemotherapy is an alternative. We present two cases of small-cell carcinoma of the lower rectum and a review of the literature.
JSLS : Journal of the Society of Laparoendoscopic Surgeons / Society of Laparoendoscopic Surgeons
Laparoscopic colorectal surgery is an established safe procedure with demonstrated benefits. Prof... more Laparoscopic colorectal surgery is an established safe procedure with demonstrated benefits. Proficiency in this specialty correlates with the volume of cases. We examined training in this surgical field for both general surgery and colon and rectal surgery residents to determine whether the number of cases needed for proficiency is being realized. We examined the Accreditation Council for Graduate Medical Education (ACGME) and American Board of Colorectal Surgeons (ABCRS) operative statistics for graduating general surgery and colon and rectal surgery residents. Although the number of advanced laparoscopy cases had increased for general surgery residents, there was still a significant gap in case volume between the average number of laparoscopic colorectal operations performed by graduating general surgery residents (21.6) and those performed by graduating colon and rectal surgery residents (81.9) in 2014. There is a gap between general surgery and colon and rectal surgery residenc...
Diseases of The Colon & Rectum, 1994
Pain after hemorrhoidectomy is widely feared by many patients who are mostly still treated with o... more Pain after hemorrhoidectomy is widely feared by many patients who are mostly still treated with oral/intramuscular narcotics to control their pain postoperatively. PURPOSE: In an effort to decrease posthemorrhoidectomy pain by applying newer methods of analgesia, a prospective trial was conducted to investigate the postoperative analgesic effect of Toradol® (ketorolac tromethamine; Syntex Labs, Palo Alto, CA) injected into the sphincter muscle at the time of hemorrhoidectomy and taken orally during a five-day postoperative period in a group of 24 patients (Toradol® group). Results were compared with two other groups of matching patients: one group (narcotics, n=18) treated with standard postoperative narcotic intramuscular/oral analgesics after overnight hospital stay, and a group (SQMP, n=21) previously treated by one of us with outpatient, subcutaneous infusion of morphine sulfate (Roxane Laboratories, Columbus, OH) via a home infusion pump. METHOD: The length of hospitalization, severity of postoperative pain and complications, costs, and side effects were analyzed by patient questionnaire at the time of the first postoperative visit and hospital and clinic records were reviewed. Differences between groups were analyzed using Student's t-test withP<0.05 being significant. RESULTS: Subjective pain response and hospitalization cost were significantly less in the SQMP group; however, this was at the expense of increased postoperative complications (urinary retention) and side effects (day until first bowel movement, nausea) although without a decrease in satisfaction rating. The Toradol® group had pain control equivalent to that of the narcotics group, a higher satisfaction rating, and suffered no increase in complications relative to either group. Significantly, there was no urinary retention in the Toradol® group. CONCLUSION: Postoperative pain after hemorrhoidectomy can be safely controlled as an outpatient using newer methods of pain control. These include both constant-infusion pain pump or supplemental use of the nonsteroidal analgesic ketorolac, both of which allow early release of the patient the day of surgery by diminishing postoperative pain. An important advantage of local injection of ketorolac is the elimination of urinary retention in our study group, probably by blunting the pain reflex response facilitated by prostaglandins, thus allowing safe same-day discharge.
Diseases of The Colon & Rectum, 1995
PURPOSE: A retrospective analysis of 48 patients treated over a 20-year period (March 1973–April ... more PURPOSE: A retrospective analysis of 48 patients treated over a 20-year period (March 1973–April 1993) was undertaken to assess the results of our practice of early surgical intervention in suppurative complications of perianal Crohn's disease. METHODS: All patients were either seen in the office within the last six months or contacted by phone. RESULTS: The average age of our patients was 30 years at initial diagnosis. Thirty-four patients (71 percent) initially presented with intestinal disease and four (8 percent) with only perianal disease. Thirteen patients (27 percent) initially presented with simultaneous intestinal and perianal disease. The various fistulas at initial presentation included 8 intersphincteric (17 percent), 14 transphincteric (29 percent), 11 complex or multiple (23 percent), 5 rectovaginal (10 percent), and 2 unclassified, for a total of 40 patients. Eight patients (17 percent) presented with only an abscess. Eighty five percent of our patients healed after their first procedure, with an average time to heal of 2.8 months. Thirteen (27 percent) patients had recurrences after initial healing of their wounds. The mean time to recurrence after healing was 5.25 years. Fifty-four percent of our recurrences (7 patients) were treated by incision and drainage of an abscess only. Seven of 13 recurrences healed after the second procedure (54 percent), and 5 of 6 healed after a third procedure (83 percent). Only seven (14 percent) of our patients underwent a proctocolectomy during the study period, through September, 1993. Our overall probability of avoiding proctectomy and healing perineal wounds of 86 percent is consistent with published literature. CONCLUSIONS: Early aggressive surgical management of suppurative complications of perianal Crohn's disease before complex management problems ensue results in a high incidence of healing and a low risk of subsequent proctectomy.
Diseases of The Colon & Rectum, 1996
Laparoscopic resection for carcinoma of the colon and rectum is currently under intense scrutiny.... more Laparoscopic resection for carcinoma of the colon and rectum is currently under intense scrutiny. PURPOSE: The purpose of this study is to review our three-year experience of laparoscopic surgery for colon and rectal carcinoma. METHODS: From October 1991 to September 1994, 76 laparoscopic procedures were performed for colorectal neoplasia (32 males and 44 females; mean age, 69 years). Fifty-five procedures were done for carcinoma, 16 for large polyps, and five for diversion in patients with unresectable cancer. For resectable tumors, the average size was 4 cm; staging was as follows: Dukes A, 10 patients; Dukes B1, 11; Dukes B2, 18; Dukes C1, 1; Dukes C2, 9; and Dukes D, 8. Fourteen cases (25 percent) that were converted to open procedures were compared with the 41 cases that were completed laparoscopically for differences in tumor size, surgical margins, number of lymph nodes harvested, length of hospital stay, and evidence of recurrence. Procedures completed laparoscopically were then compared with a group of open controls completed during the same time period. RESULTS: During the first six months, the conversion rate was 32 percent but dropped to 8 percent in the last six months. There were a total of 19 complications (25 percent), of which 8 (14 percent) were directly related to the laparoscopic technique. The mean number of lymph nodes harvested in laparoscopic resection for carcinoma was 8.5, and the average closest tumor margin was 4.5 cm. When laparoscopic resections were compared with converted and standard open colectomies, there was no significant difference in tumor margins or numbers of nodes resected. Length of stay was significantly shorter for anterior resections completed laparoscopically than for converted or conventional colectomies. Although this was also the trend for right hemicolectomies, it did not reach statistical significance. Mean follow-up of the group completed laparoscopically was 16.7 months, during which there was one recurrence. There were no trocar site recurrences. CONCLUSIONS: This early experience seems to indicate that laparoscopic surgery for colorectal carcinoma does not per se compromise surgical oncologic principles and encourages us to continue our critical appraisal of this technique.
Diseases of The Colon & Rectum, 1997
PURPOSE: The aim of this study was to test if the techniques learned during our early learning ex... more PURPOSE: The aim of this study was to test if the techniques learned during our early learning experience have proved to be effective in reducing the complications specifically related to the laparoscopic technique of colorectal surgery. METHODS: From October 1991 until July 1996, 195 laparoscopic operations were performed on the colon and the rectum. These data were divided into “early” and “latter” groups. The conversion reasons and early and late postoperative complications were analyzed and compared. RESULTS: Incidence of conversions required because of iatrogenic injuries showed a decline from 7.3 percent in the early group to 1.4 percent in the latter group. Sixty-six postoperative complications were observed in 59 (30.3 percent) patients. Complications specifically related to the technique of laparoscopic surgery occurred in nine (4.6 percent) patients. These were postoperative bleeding in three patients, port site hernias in five patients, and left ureteric stricture in one patient. Eight (6.5 percent) of these complications occurred in the early group, whereas one (1.4 percent) occurred in the latter group. Analyzing the conversions caused by intraoperative iatrogenic injuries and the specific postoperative complications together reveals that the incidence of 13.8 percent (17/123) in the early group has been reduced significantly to 2.8 percent (2/72) in the latter group. CONCLUSIONS: On the basis of our experience, we have identified techniques, which are discussed in detail, to make laparoscopic colorectal surgery safe. Strict adherence to these techniques has significantly reduced the incidence of complications, specifically those related to the laparoscopic technique.
Diseases of The Colon & Rectum, 1993
PURPOSE: Many anorectal procedures are currently being performed on an outpatient basis, hemorrho... more PURPOSE: Many anorectal procedures are currently being performed on an outpatient basis, hemorrhoidectomy being the exception because of the need for parenteral narcotics postoperatively. We investigated the effectiveness of a subcutaneous morphine pump (SQMP) for outpatient posthemorrhoidectomy pain control. METHODS: In Phase 1 of our study, 22 patients undergoing radical hemorrhoidectomy were started on an SQMP protocol postoperatively. Twenty-nine patients received conventional postoperative narcotic dosing. In Phase 2, 19 patients enrolled in an SQMP protocol underwent hemorrhoidectomy in an ambulatory setting. Length of hospitalization, catheterization rate, and pain control were evaluated. RESULTS: In Phase 1, zero patients in the study group and two in the control group required additional hospitalization beyond 23 hours for pain control. The rates of catheterization were similar between the two groups. Pain control was considered satisfactory in 21 of 22 study patients. There was no correlation between pain level and morphine dose. Eighteen of 22 patients experienced minor side effects, necessitating pump removal in two patients. In Phase 2, 18 of 19 patients on the SQMP were discharged from the recovery room. Cost analysis shows the combination of outpatient hemorrhoidectomy and the SQMP to be cost-effective in comparison with an inpatient stay. CONCLUSIONS: The SQMP enables hemorrhoidectomy to be done on an outpatient basis. It provides effective pain control, enjoys high patient acceptance, and is cost-effective.
Diseases of The Colon & Rectum, 1996
PURPOSE: This study was undertaken to assess the accuracy and ability of endorectal ultasound (ER... more PURPOSE: This study was undertaken to assess the accuracy and ability of endorectal ultasound (ERUS) to predict changes in rectal tumor stage after a preoperative chemoradiation protocol. METHODS: Since December 1990, all rectal malignancies at our institution have been preoperatively staged with ERUS. ERUS has been an essential tool in preoperative staging of rectal cancer patients, possessing an overall accuracy of 84 percent for T stage and 81 percent for lymph node status in our hands (Williamson PR, unpublished data). Beginning in July 1992, all patients staged with T3 or T4 lesions on initial ERUS have been entered into a protocol consisting of preoperative chemoradiation therapy (CRT). This protocol consists of patients receiving 4,500 to 5,040 rads for five to eight weeks and concomitantly receiving sensitizing doses of 5-fluorouracil and/or leucovorin. All patients were scheduled for sphincter-saving or abdominoperineal resections six to eight weeks following completion of CRT. A repeat ERUS was performed on each patient one week before surgery. RESULTS: The study group consisted of 15 patients who completed CRT, including 12 males and 3 females. Evidence of tumor shrinkage via ERUS measurement was seen in all patients. Average tumor shrinkage as assessed by ERUS was 16 percent by width and 32 percent by depth of invasion. Sonographic level of invasion and nodal status were each downstaged in 38 percent of patients. Pathologic evaluation comparison revealed that the level of invasion was downstaged in 47 percent and nodal status in 88 percent compared with initial ERUS staging. Of those patients downstaged, 4 of 11 (36 percent) revealed no tumor in the pathology specimen. CONCLUSIONS: We conclude from our early experience that although ERUS offers a method for assessing degree of shrinkage and downstaging of T3 and T4 lesions after CRT, presently it does not closely predict the pathologic results. Results are strongly related to the experience of the ultrasonographer. The ability to distinguish tumor from radiation-induced changes to perirectal tissues is under continued investigation, and a new method of interpreting the data obtained by ERUS after CRT will need to be established.
Diseases of The Colon & Rectum, 1997
PURPOSE: Biofeedback treatment is often offered to patients in colorectal centers; however, stand... more PURPOSE: Biofeedback treatment is often offered to patients in colorectal centers; however, standards of treatment are still lacking. A dedicated team approach is desirable but difficult to coordinate. We present our three-year experience of electromyographic-based biofeedback treatment offered within a multicenter, statewide organization. METHODS: Between October 1992 and October 1995, 188 patients completed a biofeedback treatment program in one of five coordinated centers within a 200-mile radius. A unified common database was established and continuously updated. A colorectal surgeon served as statewide director, and dedicated teams were established at each location. Each local team included the medical director and a certified biofeedback therapist and had access to a dietitian and a nurse data coordinator. Electromyographic-based biofeedback sessions were given weekly, and a home trainer program was established. RESULTS: A total of 116 patients with chronic constipation had a mean of eight (range, 2–14) weekly sessions. A total of 72 patients with fecal incontinence had a mean of seven (range, 2–11) weekly sessions. A total of 84 percent of the constipated and 85 percent of the incontinent patients had significant improvement with biofeedback treatment. Patient compliance and satisfaction were high. Constipated patients increased the mean number of weekly unassisted bowel movements from 0.8 to 6.5. Incontinent patients decreased the mean number of weekly gross incontinence episodes from 11.8 to 2. CONCLUSIONS: Biofeedback treatment can be extremely successful in both incontinent and constipated patients. A large geographic area can be covered with coordinated centers in which each dedicated team uses a unified treatment protocol, and a common database is established.
Diseases of The Colon & Rectum, 1997
INTRODUCTION: Biofeedback training is an effective modality for the treatment of chronic constipa... more INTRODUCTION: Biofeedback training is an effective modality for the treatment of chronic constipation and fecal incontinence. In general, patients express satisfaction and perceive functional improvement following biofeedback therapy; however, quantifying these observations has been difficult. AIM: This study was undertaken to evaluate the physiologic benefits of biofeedback therapy as reflected by noninvasive electromyography parameters. METHODS: Fifty-five patients who underwent computerized electromyography-based biofeedback treatment at our institution between July 1993 and July 1995 were identified. Noninvasive electromyographic testing was performed before, during (weekly), and at completion of training. Mean number of weekly sessions was seven (range, 5–11). Short-term and ten-second contractions (amplitude/μV), sustained contractions (endurance, in seconds), and net strength (μV) of the external anal sphincter before and after biofeedback were compared for differences. RESULTS: There were 30 patients with chronic constipation, mean age, 65.3 (range, 33–86) years, composed of 24 women, and 25 patients with fecal incontinence, mean age 66 (range, 34–85) years, composed of 12 males. Statistically significant improvement in endurance and net strength following biofeedback training was noted in both the constipated and the fecal incontinence groups. Fifty-three of 55 (96.4 percent) patients expressed 50 to 100 percent subjective satisfaction after biofeedback therapy. Forty-six of 55 (83.6 percent) patients demonstrated individually improved endurance. CONCLUSIONS: Sphincter endurance and net strength, as measured by noninvasive electromyography, significantly improve following biofeedback therapy in both constipated and fecal incontinence patients. These data suggest that endurance and net strength may be useful tools in assessing a benefit from biofeedback training in these patients.
Diseases of The Colon & Rectum, 2003
PURPOSE: The aim of this study was to define the long-term oncologic outcomes of laparoscopic res... more PURPOSE: The aim of this study was to define the long-term oncologic outcomes of laparoscopic resections for colorectal cancer. METHODS: We analyzed our experience via a prospective, nonrandomized, longitudinal cohort study. The period of study extended from April 1991 to May 2001. Laparoscopic resection was offered selectively in the absence of a large mass, invasion into abdominal wall or adjacent organs, and multiple prior abdominal operations. Every laparoscopic resection performed with curative intent for adenocarcinoma was included. Twenty percent of patients whose procedures were converted to open resection were included in the laparoscopic-resection group because of intention to treat. Oncologic outcome measures of this group were compared with a computerized, case-matched, open-resection group, the case-matching variables being age, gender, site of primary tumor (colon vs. rectum), and TNM stage. The laparoscopic-resection group was followed up prospectively, and data were updated regularly. The follow-up techniques consisted of a combination of office visits, telephone calls, and the United States Social Security Death Index database. RESULTS: The laparoscopic-resection group consisted of 172 patients with a mean age of 67 (range, 27–85) years. The open-resection group consisted of 172 patients with a mean age of 69 (range, 30–90) years. Mean follow-up was 52 (range, 3–128) months. Complete (100 percent) follow-up data were available. The TNM stage distribution was 63 Stage I (37 percent), 51 Stage II (30 percent), 47 Stage III (27 percent), and 11 Stage IV (6 percent) tumors for the laparoscopic-resection group and 65 Stage I (38 percent), 48 Stage II (28 percent), 51 Stage III (29 percent), and 8 Stage IV (5 percent) tumors for patients in the open-resection group (P = 0.75, not significant). Thirty-day mortality was 1.2 percent (2 deaths) in the laparoscopic-resection group and 2.4 percent (4 deaths) in the open-resection group (P > 0.05, not significant). Early and late complication incidences were comparable. Local recurrence was observed in three patients (1.7 percent) in the laparoscopic resection group with the primary tumor in the colon and in three patients (1.7 percent) with the primary tumor in the rectum, for a total incidence of local recurrence in the laparoscopy group of 3.5 percent (6 patients). In the open-resection group, local recurrence was observed in two patients (1.2 percent) among those with primary tumor site in the colon and in three patients (1.7 percent) in the group with primary tumor in the rectum, for a total incidence of local recurrence in the open-resection group of 2.9 percent (5 patients). One of the local recurrences in the laparoscopy group occurred in the port/extraction site, for an incidence of 0.6 percent. Metastasis occurred in 18 patients (10.5 percent) in the open group and in 21 (12.2 percent) in the laparoscopy group. Stage-for-stage overall five-year survival rates were similar in the two groups. The Kaplan-Meier statistical analysis performed for colonic vs. rectal primary adenocarcinoma confirmed that TNM stage for stage-overall survival was similar in the laparoscopic and open-resection groups (log-rank P = 0.22). CONCLUSIONS: Notwithstanding the drawbacks of a nonrandomized study, no adverse long-term oncologic outcomes of laparoscopic resections for colorectal cancer were observed in a single center’s experience during a ten-year period.
Uploads
Papers by Paul Williamson