Review for 10.1186/s12876-015-0396-x (2015)

Reviewer's report
Title:Immunohistochemical Expression and Outcome in Curatively Resected
Ampulla of Vater Cancer
Version:2Date:12 August 2015
Reviewer: Jae-Hoon Lee
Reviewer's report:
Authurs analyzed the prognostic significance of IHC subtype in term of CK7 and
CK20. This study has sufficient clinical interest and importance, and manuscript
is well written and organized. But population size is small and statistical analys
should be refined in some parts. And poor prognosis of CK7+/CK20- was already
reported.
Major Compulsory Revisions
][
1. RESULT SECTION
- In general, minimum of 100 subjects is considered to be sufficient for a factor
analysis study, and the ratio of cases to variables should be at least 10:1. In the
present study with 37 AoV carcinoma patients, however, too many factors were
evaluated in the multivariate analysis. Authors need to minimize the number of
variables that should be included in multivariate analysis.
2. RESULT SECTION
- Authors analyzed both histologic type (PB type vs. intestinal type) and
CK7+/CK20- simultaneously in the multivariate analysis. But, CK7+/CK20- type is
significantly more common in PB type than intestinal type (by chi-square test)
and CK7+/CK20- often refers to PB type. This means, there is potential
collinearity between two variables - histologic type and IHC type - and therefore it
is not recommend to analyze those variables simultaneously in the multivariate
analysis.
3. METHODS SECTION
- all included AOV carcinomas were clearly divided into two types. Was there any
mixed or other histologic types? In addition, this study lacks confirmation of
histologic subtype by testing expression of MUC1 and CDX2, etc, thus it needs to
be mentioned in limitation-like part of the discussion section.
4. METHODS SECTION, PATIENTS PART
- Type of surgery needs to be documented.
5. RESULT SECTION AND TABLES
- Authors dichotomize patients according to CA19-9 and total bilirubin levels with
cutoff values of 200 and 10, respectively. Please provide the rationales for those
values.
6. RESULT SECTION
- I recommend that survival graphs (CK7+/CK20- vs. others; with censored data
marked) be added to clearly show the differences in survival outcome.
- Minor Essential Revisions
- Discretionary Revisions
1. DISCUSSION SECTION, THE LAST SENTENCE OF 4TH PARAGRAPH
- Authors suggest patients with AOVC of CK7+/CK20- can be considered as
candidates for adjuvant treatment. Generally adjuvant treatment can be
considered for those who have high risk of recurrence if the adjuvant treatment
has a definite survival benefit. In contrast, for AOVC, only a few randomized trials
have been performed and its survival benefit is still under debate. Data is limited
but better treatment outcome is reported for patients with intestinal type AOVC.
So please could you explain why the authors are considering adjuvant treatment
for +/- type AOVC that is dominanttype of PB AOVC?
2. TABLES
- Tables seem redundant. Table-2 can be omitted as long as the main idea is not
affected, because it is also mentioned in discussion section. Table 3 and 4 can
be merged together, and Table 5 and 6 as well. In addition, IHC types which are
not of clinical interest or importance can be omitted. Last, (+) and (-) for LN, LVI,
PNI can be changed in to yes/no or positive/negative.
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests