The prognosis for gastric carcinoma depends to a large extent on both depth of tumor penetration and metastasis to lymph nodes; tumor diameter is generally not considered an independent prognostic factor . Tumor size is usually the most important factor when determining the division line during gastrectomy. It is not used, however, to indicate the extent of progression of a gastric carcinoma or the appropriate surgical procedure, such as lymphadenectomy or combined resection of neighboring organs.
This situation would change if the tumor size of gastric carcinoma was proven to be predictive of biologic malignancy. Knowledge of the three-dimensional shape and volume of a tumor is essential for understanding its true morphology and size. In recent years the ease of creating three-dimensional reconstruction from two-dimensional data has markedly increased because of advances in computer graphics technology. It may lead to a new tumor classification system for gastric cancer and influence therapeutic approaches in oncology based on a new concept of the extent of tumor progression.
The Kikuchi's study is limited to early and early-like advanced gastric carcinoma patients and does not encompass all types of gastric carcinoma.
Altogether 105 primary gastric carcinoma lesions, consisting of 16 advanced and 89 early carcinomas, are analyzed. A total of 942 lesion tissue sections, comprising 2 to 37 sections per lesion (mean 9 sections), are examined histologically. Surface rendering using a computer graphics analysis program is then performed from serial sections to create a three-dimensional reconstruction of tumor morphology from which to measure tumor volume.
In conclusion, conventional measurements of tumor diameter as a rough indicator of tumor size can predict the actual tumor size of a gastric carcinoma. Three-dimensional reconstruction using computer graphics provides a better estimation of true tumor size and extent of progression than tumor diameter
( 1 ).
Several parameters, including DNA ploidy, detection of products of oncogenes, and immunohistochemical detection of proliferative activity of cancer cells, have been offered as prognostic indicators for patients with advanced gastric cancer. However, determination of these parameters requires complex and difficult techniques. Nuclear profiles, such as the size of the nuclear area or nuclear shape, have recently been suggested as useful predictors of prognosis in various cancers. Interactive computerized morphometry is a quantitative technique that measures nuclear size and the shape of cancer cells. The resulting data are objective, and the technique is quickly performed using conventional microscopic analysis.
In the Ikeguchi's study morphometric nuclear features (nuclear area, perimeter, and shape) are analyzed in 202 patients with serosal-invaded gastric cancer (stage II and III) who underwent curative gastrectomy.
Lymph node metastasis, lymphatic invasion, and venous invasion are more frequently detected in patients with large nuclear areas. Significant correlations are detected between the size of the nuclear area of cancer cells and the biologic factors of tumors, such as expression of p53, Ki-67 labeling index, and DNA ploidy pattern. The 5-year survival rate of the 100 patients in the large-nuclear group (nuclear area >45.3 m2) is 47.6% and is significantly lower than the 74.4% rate of the 98 patients in the small-nuclear group (nuclear area 45.3 m2). Moreover, the nuclear area is found to be an independent prognostic factor in the multivariate analysis
( 2 ).
Guadagni et al. evaluate the accuracy of the Maruyama computer program for preoperative estimation of lymph node metastases from gastric cancer, in 282 italian patients submitted to curative gastrectomy and D2 or more extended LN dissections for gastric cancer.
In fact controversy still exist about the optimal lymph node dissection for potentially curable gastric cancer. For rationale LN dissection it is important to know the incidence of metastasis at each LN station.
The program predicts with good accuracy the extent of LN metastases from gastric cancer, but it is not recommended for directing the surgeon to perform more extensive lymphadenectomy
( 4 ).
References
1) Shiro Kikuchi, M.D.1, Yoshiki Hiki, M.D.1, Yuzuru Sakakibara, M.D.1, Akira.Measuring the Tumor Volume of Gastric Carcinoma by Computer Image Analysis: Clinical Significance. World J. Surg. 24, 603 (2000).
2) Masahide Ikeguchi, MD; Shinichi Oka, MD; Hiroaki Saito, MD; Akira Kondo, MD; Shunichi Tsujitani, MD; Michio Maeta, MD; Nobuaki Kaibara, MD. Computerized Nuclear Morphometry. Annals of Surgery 1999;229:55-61
3) Tosi P, Luzi P, Baak JPN, et al. Nuclear morphometry as an important prognostic factor in stage I renal cell carcinoma. Cancer 1986; 58:2512-2518.
4) Stefano Guadagni, Giovanni de Manzoni, Marco Catarci, Marco Valenti, Gianfranco Amicucci, Giancarlo De Bernardinis, Claudio Cordiano, Manlio Carboni, Keiichi Maruyama. Evaluation of the Maruyama computer program accuracy for preoperative estimation of lymph node metastases from gastric cancer. World J Surg 24, 1550-1558, 2000.
