Recommendations for radiation ports in adjuvant radiation therapy for rectal cancer are mainly based on analysis of recurrence patterns. To evaluate whether changes in surgical technique have influenced this pattern of recurrence, a multicenter retrospective analysis was carried out on a patient population treated recently.

BACKGROUND AND PURPOSE:Recommendations for radiation ports in adjuvant radiation therapy for rectal cancer are mainly based on analysis of recurrence patterns. To evaluate whether changes in surgical technique have influenced this pattern of recurrence, a multicenter retrospective analysis was carried out on a patient population treated recently.PATIENTS AND METHODS:123 patients were evaluated with the help of a CT-based self-developed 3-D data file system and an extensive questionnaire. Major inclusion criteria (one sufficient) for eligibility were: histological confirmation, clear bone destruction, and a positive PET scan, or at least three minor criteria: progressive soft tissue mass, invasion of adjacent organs on follow-up CT or MRI, rising tumor markers, and typical appearance in cross-sectional imaging. Clinical or serologic signs of inflammation were exclusion criteria.RESULTS:Initially, 54% of the evaluated patients were N0; in the remainder, N1 and N2 were distributed evenly. Initial T-category was T1 in 2%, T2 in 24%, T3 in 60%, and T4 in 13%, the male-to-female ratio was 2:1. Recurrent tumors were mainly situated in the posterior part of the bony pelvis as displayed in the figures. When abdominoperineal resection was compared to low anterior resection as primary operation, there was a significant difference in extension of recurrent tumors in the inferior parts of the pelvis (p<0.025 in all statistical tests applied), whereas no significant difference was found in the superior parts of the pelvis.CONCLUSION:Based on these results, a modest field size reduction in adjuvant radiotherapy for rectal cancer seems feasible, offering the perspective of a reduction in acute and late side effects.

Background and aims. The lateral pelvic sidewall is an area not routinely dissected during standard operative procedures in surgery for rectal cancer in Western countries. This study analyzed data to evaluate the pattern of recurrence in rectal cancer with special emphasis on lateral tumor extension in a recently treated patient population. Patients and methods. In a multicenter retrospective study 123 patients were evaluated by our own CT-based three-dimensional datafile system and an extensive questionnaire. Patients had histological confirmation, clear bone destruction, a positive PET scan, and at least three minor criteria: progressive soft tissue mass, invasion of adjacent organs on follow-up CT or MRI, rising tumor markers, and typical appearance in cross-sectional imaging. Clinical or serological signs of inflammation were exclusion criteria. Initially 54% of the evaluated patients were N0, and the others were distributed evenly between N1 and N2; initial T stage was T1 in 2%, T2 in 24%, T3 in 60%, and T4 in 13%. Results. Recurrent tumors were situated mainly in the posterior part of the bony pelvis. The pelvic side wall was a rare site of recurrence and involved in fewer than 5%. When abdominoperineal resection was compared to low anterior resection as primary operation, there was a significant difference in extension of recurrent tumors in the inferior parts of the pelvis; no significant differences were found in superior or lateral parts of the pelvis. Conclusion. Because most tumor recurrences arise in the central pelvis, extending surgery to include dissecting the iliac vessels would probably offer only a moderate benefit, which must be balanced against potential side effects.

Concerns have been raised about harmful effects of radiotherapy, especially in older patients. In one meta-analysis,1Colorectal Cancer Collaborative Group Adjuvant radiotherapy for rectal cancer: a systematic overview of 8507 patients from 22 randomised trials.Lancet. 2001; 358: 1291-1304Summary Full Text Full Text PDF PubMed Scopus (892) Google Scholar the researchers concluded this risk may in part be caused by outdated radiotherapy techniques since parallel opposed field arrangements had been used in many of the studies assessed. Use of a more advanced treatment set-up, such as conformal radiotherapy, with which the optimum target volume for adjuvant radiotherapy is defined, is essential to reduce side-effects without compromising efficacy, since salvage in recurrent disease is seldom achievable.2Wiig JN Tveit KM Poulsen JP et al.Preoperative irradiation and surgery for recurrent rectal cancer: will intraoperative radiotherapy (IORT) be of additional benefit? A prospective study.Radiother Oncol. 2002; 62: 207-213Summary Full Text Full Text PDF PubMed Scopus (97) Google Scholar Precise data on pelvic sites of recurrence are rare and sometimes outdated because major changes in operative procedures have been adopted in the past few years.3Gunderson LL Sosin H Areas of failure found at reoperation (second or symptomatic look) following “curative surgery” for adenocarcinoma of the rectum: clinicopathologic correlation and implications for adjuvant therapy.Cancer. 1974; 34: 1278-1292Crossref PubMed Scopus (673) Google Scholar, 4Bagatzounis A Kölbl O Mueller G et al.Das lokoregionäre Rezidiv des Rektumkarzinoms. Eine comutertomographische Analyse und ein Zielvolumenkonzept für die adjuvante Radiotherapie.Strahlenther Onkol. 1997; 173: 68-75Crossref PubMed Google Scholar, 5MacFarlane JK Ryall RD Heald RJ Mesorectal excision for rectal cancer.Lancet. 1993; 341: 457-460Summary PubMed Scopus (1555) Google Scholar We have analysed the location of recurrent rectal cancer in the pelvis in 122 patients with a three-dimensional CT-based data-file system. To be included, patients had to have one of the major criteria—histological confirmation of recurrent disease, clear evidence of bone destruction on CT or MRI, or a positive positron-emission tomography scan—or at least three of the following minor criteria: progressive soft-tissue mass on repeated CT or MRI examinations; invasion of adjacent organs; typical appearance on CT, MRI, or endoscopic ultrasonography; and consecutive rise of tumour markers. Clinical or serological signs of inflammation or abscess formation were exclusion criteria. Exclusion of areas involved in less than 5%, as shown in the figure, shows a pattern of involved sites that may provide a guide to target radiation ports to an essential minimum and, therefore, reduce toxic effects.