Tumor volume regression during preoperative chemoradiotherapy for rectal cancer: a prospective observational study with weekly MRI.
Acta Oncol
; 57(6): 723-727, 2018 Jun.
Article
in En
| MEDLINE
| ID: mdl-29157069
ABSTRACT
PURPOSE:
Few data is available on rectal tumor shrinkage during preoperative chemoradiotherapy (CRT). This regression pattern is interesting to optimize timing of dose escalation on the tumor.METHODS:
Gross tumor volumes (GTV) were contoured by two observers on magnetic resonance imaging (MRI) obtained before, weekly during, 2-4 weeks after, and 7-8 weeks after a 5-week course of concomitant CRT for rectal cancer.RESULTS:
Overall, 120 MRIs were acquired in 15 patients. A statistically significant tumor volume reduction is seen from the first week, and between any two time points (p < .007). At the end of CRT, 46.3% of the initial tumor volume remained, and 32.4% at time of surgery. PTV measured 61.2% at the end of treatment. Tumor shrinkage is the fastest in the beginning of treatment (26%/week), slows down to 7%/week in the last 2 weeks of CRT, and finally to 1.3%/week in the last 5 weeks before surgery.CONCLUSIONS:
The main rectal tumor regression occurs during CRT course itself, and mostly in the first half, with shrinking speed decreasing over the course. This suggests that a sequential boost is preferably done after the elective fields, yielding an average PTV-reduction of 39%. A simultaneous integrated boost strategy could benefit from adaptive planning during the course.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Rectal Neoplasms
/
Adenocarcinoma
/
Chemoradiotherapy, Adjuvant
Type of study:
Observational_studies
Limits:
Adult
/
Aged
/
Female
/
Humans
/
Male
/
Middle aged
Language:
En
Journal:
Acta Oncol
Journal subject:
NEOPLASIAS
Year:
2018
Document type:
Article
Affiliation country:
Belgium
Publication country:
ENGLAND
/
ESCOCIA
/
GB
/
GREAT BRITAIN
/
INGLATERRA
/
REINO UNIDO
/
SCOTLAND
/
UK
/
UNITED KINGDOM