Instrumental clinical restaging, pathological evaluation, and tumor regression grading: how to assess the response to neoadjuvant chemoradiotherapy for rectal cancer.
BACKGROUND
The object of neoadjuvant chemoradiotherapy regimens is a downstaging or downsizing of advanced rectal tumor to increase the rate of curative resection and reduce loco-regional failure. A reliable method of assessing response to adjuvant therapies is required to help standardize the assessments of new multimodality therapies. The purpose of this study was to evaluate the role played by tumor regression grading on the evaluation of pathological response to chemoradiotherapy, compared with both the predicting value of the clinical response to neoadjuvant therapy and pathologic response evaluation.


METHODS
From 1994 to 2003, 58 patients with a primary diagnosis of rectal cancer were studied at our department and enrolled in a single center, not randomized study based on 5-week sessions of radiotherapy associated with a 30-day 5-fluorouracil (FU) infusion, followed by surgical resection. Instrumental restaging and routine histological examination, including tumor regression grading, were performed to asses the response to neoadjuvant therapy.


RESULTS
The cCR rate corresponds to pCR rate, while a 3.5% of cPR and a 3.4% of cSD corresponded to a pPD. cPR and cSD show a PPV of 92.8% and 90.9% respectively, while cPD NPV is 20%. No case was found with no regression (grade 0). Tumor regression was defined grade 1 in 24.5% of cases, grade 2 was found in 58.5% of cases, 7.5% were grade 3, and 9.5% showed complete regression (grade 4). Pathologic response resulted to be associated with regression grade (p=0.006). Tumor regression grading is an independent variable for pT (p=0.0002), pN status (p=0.00004), pathologic staging (p=0.000001) and local recurrence (p=0.003).


CONCLUSIONS
Our results lead us to consider only pathologic evaluation to determine the response to neoadjuvant treatment: the application of tumor regression grading on the specimens obtained after combined neoadjuvant chemoradiotherapy and surgery is useful to plan a better therapeutic strategy on the ground of a quantitative evaluation of the response to neoadjuvant treatment; it shows it is an important comparable pathological feature, useful in comparing different protocols' results and differences between patient's response as well as prognostic factors.
Benzoni
Enrico
E
Department of Surgery, University of Udine, School of Medicine, Udine, Italy. enricobenzoni@yahoo.it
Terrosu
Giovanni
G
Intersimone
Donatella
D
Milan
Elisa
E
Chiaulon
Germana
G
Bresadola
Vittorio
V
Sacco
Cosimo
C
Sattin
Elisa
E
Bresadola
Fabrizio
F
Avellini
Claudio
C
D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001706:Biopsy; D003113:Colonoscopy; D018450:Disease Progression; D019160:Endosonography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging / Q000379:methods*; D012004:Rectal Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000532:radiotherapy; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
D000970:Antineoplastic Agents