Pre-treatment platelet counts as a prognostic and predictive factor in stage II and III rectal adenocarcinoma

Table 1 Baseline characteristics of all patients in the series and comparison of the groups with lower (≤ 300 × 10⁹/ L) and higher (> 300 × 10⁹/ L) platelet counts n (%)

	Total (%) (n = 51)	≤300 (n = 26)	> 300 (n = 25)	χ2
Age (yr)
> 60	21 (41.2)	10 (38.5)	11 ( 44.0)	P = 0.69
≤ 60	30 (58.8)	16 (61.5)	14 (56.0)
Clinical stage
II	25 (49.0)	15 (57.7)	10 (40.0)	P = 0.21
III	26 (51.0)	11 (42.3)	15 (60.0)
CEA (n = 50)
> 5	25 (50.0)	11 (44.0)	14 (56.0)	P = 0.4
< 5	25 (50.0)	14 (56.0)	11 (44.0)
Symptoms
Obstruction/pain	13 (25.5)	6 (23.1)	7 (28.0)	P = 0.69
Bleeding/ asymptomatic	38 (74.5)	20 (76.9)	18 (72.0)
Type of surgery
Anterior resection	27 (52.9)	13 (50.0)	14 (56.0)	Anterior resection vs
APR	19 (37.3)	11 (42.3)	8 (32.0)	APR/exenteration
Pelvic/exenteration	2 (3.9)	0	2 (8.0)	P = 0.77
None	3 (5.9)	2 (7.7)	1 (4.0)
Pathologic response
No response	15 (29.4)	8 (30.8)	7 (28.0)	No/minimal/
Minimal	7 (13.7)	4 (15.3)	3 (12.0)	Moderate resp vs
Moderate	15 (29.4)	3 (11.6)	12 (48.0)	Good/complete
Good	5 (9.8)	5 (19.2)	0	P = 0.015
Complete	9 (17.6)	6 (23.1)	3 (12.0)
Lymph nodes at surgery
Negative	31 (60.8)	15 (57.7)	16 (64.0)	P = 0.61
Positive	16 (31.4)	9 (34.6)	7 (28.0)
No surgery	3 (5.9)	2 (7.7)	1 (4.0)

Pre-operative CEA not available in one patient. Lymph node evaluation was not available in the pathology report in one patient. APR: Abdomino-perineal resection; CEA: Carcinoembryonic antigen.

Table 2 Comparison of characteristics of patients according to their pathologic response at surgery (n = 48) or at post-neoadjuvant treatment endoscopy (n = 3) n (%)

	No response/minimal/moderate	Good/ complete	χ2P value
Age (yr)
> 60	13 (35.1)	8 (57.1)	0.15
≤ 60	24 (64.9)	6 (42.9)
Clinical stage
II	16 (43.2)	9 (64.3)	0.18
III	21 (56.8)	5 (35.7)
CEA (n = 50)
> 5	24 (64.9)	1 (7.7)	0.0004
< 5	13 (35.1)	12 (92.3)
Symptoms
Obstruction/pain	12 (32.4)	1 (7.1)	0.06
Bleeding/asymptomatic	25 (67.6)	13 (92.9)
Platelets
≤ 300	15 (40.5)	11 (78.6)	0.015
> 300	22 (59.5)	3 (21.4)

Pre-operative CEA not available in one patient. CEA: Carcinoembryonic antigen.

Table 3 Logistic regression analysis of pathologic response (complete or good vs moderate or minimal or no response) as the outcome variable and platelet counts (≤vs > 300 × 10⁹/L), carcinoembryonic antigen (≤ 5 μg/L vs > 5 μg/L) and symptoms (obstruction or pain vs bleeding or asymptomatic) at presentation as the predictor variables

Variable	OR	95%CI	P value
Platelet count	0.15	0.02-0.85	0.03
CEA	0.04	0.004-0.41	0.006
Symptoms at presentation	4.7	0.39-55.8	0.20

CEA: Carcinoembryonic antigen.