Inadvertent spread of cancer at surgery

Transmission of Genetic Material and Malignant Cells of Cutaneous Origin via Surgical Sutures

BACKGROUND

Seeding of skin cancer cells following diagnostic or therapeutic surgical procedures can occur and might cause local recurrences. As current preferred therapy for skin malignancy is surgical excision, seeding of tumour cells by manipulating malignant tissue or suturing can be another factor leading to recurrences.

OBJECTIVE

To evaluate whether genetic material and malignant cells adhere to standard suture materials.

METHODS

This prospective study included patients who underwent excision of skin lesions. Monofilament and braided sutures were examined. Sutures were passed through the observed tumour or healthy skin margins and were examined for DNA material and cells by cytological analysis, cell culture and characterization, and DNA analysis.

RESULTS

Twenty-two patients and 148 sutures were included. DNA quantification showed DNA material on all sutures, with no significant difference between braided and monofilament sutures. Cytological analysis showed that all slides prepared from cell blocks contained normal squamous and atypical cells. Cell culture and characterization showed viable cells adhering to the sutures under direct light microscopy. Cell cultures showed rapid proliferation of epithelial cells from squamous cell carcinoma specimens.

CONCLUSION

Suture materials carry DNA material and cells, including malignant cells of cutaneous origin and may seed them at distant sites.

The use of oncolytic virotherapy in the neoadjuvant setting

Surgical removal of tumors remains a front-line therapy for many types of cancer. However, this treatment often fails to eradicate disease due to either recurrence of the original tumor or development of distant micrometastases. To address these challenges, patients are often given non-curative treatments presurgery with the intent of improving surgical outcomes. These treatments, collectively known as neoadjuvant therapies, have traditionally focused on the presurgical use of chemotherapeutics. Recently, however, a variety of immunotherapies have also been identified as potentially effective in the neoadjuvant setting. One of these immunotherapies is oncolytic virotherapy, whose clinical use has exploded with the Food and Drug Administration approval of Talimogene Laherparepvec. This review summarizes both the preclinical and clinical literature examining the use of oncolytic virotherapy in the neoadjuvant setting for different types of cancers and discusses some of the major questions that still need to be addressed in order for this unique use of immunotherapy to become clinically viable.

Association of postoperative influenza vaccine on overall mortality in patients undergoing curative surgery for solid tumors

Recent findings have found that the influenza vaccine induces changes in the immune system in favor of antitumor cytotoxicity. The aim of our study was to investigate if an influenza vaccine given in the postoperative period decreased overall and cancer-specific mortality in patients undergoing curative surgery for solid cancers. We conducted a registry-based national observational study in Denmark in the period January 1, 2010 to December 31, 2015 with a follow-up period of 3 years starting from 180 days after surgery. Patients with solid cancers undergoing curative surgery were included. The primary outcome was overall mortality. The secondary outcome was cancer-specific mortality. A total of 21 462 patients were included in the study with 2557 patients receiving an influenza vaccine within 6 months after surgery. In a Cox regression model, a decrease in overall mortality (hazard ratio [HR] = 0.89, 95% confidence interval [CI] = 0.81-0.99, P = .03) and cancer-related mortality (HR = 0.82, 95% CI = 0.71-0.93, P = .003) was found among patients given a vaccine vs patients never receiving a vaccine. In a predefined subgroup of patients receiving a vaccine within 30 days after surgery, a decrease in overall mortality (HR = 0.82, 95% CI = 0.72-0.94, P = .007) and cancer-specific mortality (HR = 0.70, 95% CI = 0.53-0.91, P = .009) was found. No association was evident in patients receiving the vaccine after 30 days to 6 months after surgery (overall mortality: HR = 0.96, 95% CI = 0.86-1.07, P = .46); cancer-specific mortality: HR = 0.88, 95% CI = 0.76-1.03, P = .12). These findings must be investigated in larger clinical trials where both immunological biomarkers and survival outcomes are included.

Anti-Tumor Potential of a 5-HT3 Receptor Antagonist as a Novel Autophagy Inducer in Lung Cancer: A Retrospective Clinical Study with In Vitro Confirmation

Unlike 5-hydroxytryptamine (5-HT, serotonin) 1 and 5-HT2, the effect of 5-HT3 receptors on tumor cells is poorly understood. We conducted this study to determine whether the perioperative use of 5-HT3 receptor antagonists, which are widely used antiemetics, impacts the recurrence and mortality after lung cancer surgery and related anti-tumor mechanisms. From data on 411 patients, propensity score matching was used to produce 60 1:2 matched pairs of patients, and variables associated with the prognosis after open lung cancer surgery were analyzed. Additionally, the effects of 5-HT3 receptor antagonists were confirmed in vitro on A549 human lung adenocarcinoma cells. Cancer recurrence occurred in 10 (8.2%) and 14 (22.95%) patients (p = 0.005), treated or untreated, with palonosetron or ramosetron. Perioperative usage of palonosetron or ramosetron was also associated with lower recurrence rate after lung cancer surgery (hazard ratio (HR), 0.293; 95% confidence interval (CI) 0.110-0.780, p = 0.0141). Our in vitro experiments also showed that palonosetron and ramosetron inhibited cell proliferation and colony formation and reduced migration, which was associated with autophagic cell death via the extracellular signal-regulated kinase (ERK) pathway. Palonosetron and ramosetron may have anti-tumor potential against lung cancer cells, suggesting the need to consider these drugs as first-choice antiemetics in patients undergoing lung cancer surgery.

Combining surgery and immunotherapy: turning an immunosuppressive effect into a therapeutic opportunity

Background

Cancer surgery is necessary and life-saving. However, the majority of patients develop postoperative recurrence and metastasis, which are the main causes of cancer-related deaths. The postoperative stress response encompasses a broad set of physiological changes that have evolved to safeguard the host following major tissue trauma. These stress responses, however, intersect with cellular mediators and signaling pathways that contribute to cancer proliferation.

Main

Previous descriptive and emerging mechanistic studies suggest that the surgery-induced prometastatic effect is linked to impairment of both innate and adaptive immunity. Existing studies that combine surgery and immunotherapies have revealed that this combination strategy is not straightforward and patients have experienced both therapeutic benefit and drawbacks. This review will specifically assess the immunological pathways that are disrupted by oncologic surgical stress and provide suggestions for rationally combining cancer surgery with immunotherapies to improve immune and treatment outcomes.

Short conclusion

Given the prevalence of surgery as frontline therapy for solid cancers, the emerging data on postoperative immunosuppression and the rapid development of immunotherapy for oncologic treatment, we believe that future targeted studies of perioperative immunotherapy are warranted.

Risk of leptomeningeal carcinomatosis in patients with brain metastases treated with stereotactic radiosurgery

There is limited available literature examining factors that predispose patients to the development of LMC after stereotactic radiosurgery (SRS) for brain metastases. We sought to evaluate risk factors that may predispose patients to LMC after SRS treatment in this case-control study of patients with brain metastases who underwent single-fraction SRS between 2011 and 2016. Demographic and clinical information were collected retrospectively for 19 LMC cases and 30 controls out of 413 screened patients with brain metastases. Risk factors of interest were evaluated by univariate and multivariate logistic regression analyses and overall survival rates were evaluated by Kaplan-Meier survival analysis. About 5% of patients with brain metastases treated with SRS developed LMC. Patients with LMC (median 154 days, 95% CI 33-203 days) demonstrated a poorer overall survival than matched controls (median 417 days, 95% CI 121-512 days, p = 0.002). The most common primary tumor histologies  that lead to the development of LMC were non-small cell lung cancer (36.8%), breast cancer (26.3%), and melanoma (21.1%). No association was found between the risk of LMC and the location of the brain lesion or total volume of brain metastases. Prior surgical resection of brain metastases before SRS was associated with a 6.5 times higher odds (95% CI 1.45-29.35, p = 0.01) of developing LMC post-radiosurgery compared to those with no prior resections of brain metastases. Additionally, adjuvant WBRT may help to reduce the risk of LMC and can be considered in decision-making for patients who have had brain metastasectomy.

Attacking Postoperative Metastases using Perioperative Oncolytic Viruses and Viral Vaccines

Surgical resection of solid primary malignancies is a mainstay of therapy for cancer patients. Despite being the most effective treatment for these tumors, cancer surgery has been associated with impaired metastatic clearance due to immunosuppression. In preclinical surgery models and human cancer patients, we and others have demonstrated a profound suppression of both natural killer (NK) and T cell function in the postoperative period and this plays a major role in the enhanced development of metastases following surgery. Oncolytic viruses (OV) were originally designed to selectively infect and replicate in tumors, with the primary objective of directly lysing cancer cells. It is becoming increasingly clear, however, that OV infection results in a profound inflammatory reaction within the tumor, initiating innate and adaptive immune responses against it that is critical for its therapeutic benefit. This anti-tumor immunity appears to be mediated predominantly by NK and cytotoxic T cells. In preclinical models, we found that preoperative OV prevents postoperative NK cell dysfunction and attenuates tumor dissemination. Due to theoretical safety concerns of administering live virus prior to surgery in cancer patients, we characterized safe, attenuated versions of OV, and viral vaccines that could stimulate NK cells and reduce metastases when administered in the perioperative period. In cancer patients, we observed that in vivo infusion with oncolytic vaccinia virus and ex vivo stimulation with viral vaccines promote NK cell activation. These preclinical studies provide a novel and clinically relevant setting for OV therapy. Our challenge is to identify safe and promising OV therapies that will activate NK and T cells in the perioperative period preventing the establishment of micrometastatic disease in cancer patients.

Risk of tumor cell seeding through biopsy and aspiration cytology

Cancer cells, besides reproducing uncontrollably, lose cohesiveness and orderliness of normal tissue, invade and get detached from the primary tumor to travel and set up colonies elsewhere. Dislodging neoplastically altered cells from a tumor during biopsy or surgical intervention or during simple procedure like needle aspiration is a possibility because they lack cohesiveness, and they attain the capacity to migrate and colonize. Considering the fact that, every tumor cell, is bathed in interstitial fluid, which drains into the lymphatic system and has an individualized arterial blood supply and venous drainage like any other normal cell in our body, inserting a needle or a knife into a tumor, there is a jeopardy of dislodging a loose tumor cell into either the circulation or into the tissue fluid. Tumor cells are easier to dislodge due to lower cell-to-cell adhesion. This theory with the possibility of seeding of tumor cells is supported by several case studies that have shown that after diagnostic biopsy of a tumor, many patients developed cancer at multiple sites and showed the presence of circulating cancer cells in the blood stream on examination. In this review, we evaluate the risk of exposure to seeding of tumor cells by biopsy and aspiration cytology and provide some suggested practices to prevent tumor cell seeding.

Preventing postoperative metastatic disease by inhibiting surgery-induced dysfunction in natural killer cells

Natural killer (NK) cell clearance of tumor cell emboli following surgery is thought to be vital in preventing postoperative metastases. Using a mouse model of surgical stress, we transferred surgically stressed NK cells into NK-deficient mice and observed enhanced lung metastases in tumor-bearing mice as compared with mice that received untreated NK cells. These results establish that NK cells play a crucial role in mediating tumor clearance following surgery. Surgery markedly reduced NK cell total numbers in the spleen and affected NK cell migration. Ex vivo and in vivo tumor cell killing by NK cells were significantly reduced in surgically stressed mice. Furthermore, secreted tissue signals and myeloid-derived suppressor cell populations were altered in surgically stressed mice. Significantly, perioperative administration of oncolytic parapoxvirus ovis (ORFV) and vaccinia virus can reverse NK cell suppression, which correlates with a reduction in the postoperative formation of metastases. In human studies, postoperative cancer surgery patients had reduced NK cell cytotoxicity, and we show for the first time that oncolytic vaccinia virus markedly increases NK cell activity in patients with cancer. These data provide direct in vivo evidence that surgical stress impairs global NK cell function. Perioperative therapies aimed at enhancing NK cell function will reduce metastatic recurrence and improve survival in surgical cancer patients.

Incidence and risk factors for leptomeningeal carcinomatosis in breast cancer patients with parenchymal brain metastases

OBJECTIVE

The objective of study is to evaluate the incidence of leptomeningeal carcinomatosis (LMC) in breast cancer patients with parenchymal brain metastases (PBM) and clinical risk factors for the development of LMC.

METHODS

We retrospectively analyzed 27 patients who had undergone surgical resection (SR) and 156 patients with whole brain radiation therapy (WBRT) as an initial treatment for their PBM from breast cancer in our institution and compared the difference of incidence of LMC according to clinical factors. The diagnosis of LMC was made by cerebrospinal fluid cytology and/or magnetic resonance imaging.

RESULTS

A total of 27 patients (14%) in the study population developed LMC at a median of 6.0 months (range, 1.0-50). Ten of 27 patients (37%) developed LMC after SR, whereas 17 of 156 (11%) patients who received WBRT were diagnosed with LMC after the index procedure. The incidence of LMC was significantly higher in the SR group compared with the WBRT group and the hazard ratio was 2.95 (95% confidence interval; 1.33-6.54, p<0.01). Three additional factors were identified in the multivariable analysis : the younger age group (<40 years old), the progressing systemic disease showed significantly increased incidence of LMC, whereas the adjuvant chemotherapy reduce the incidence.

CONCLUSION

There is an increased risk of LMC after SR for PBM from breast cancer compared with WBRT. The young age (<40) and systemic burden of cancer in terms of progressing systemic disease without adjuvant chemotherapy could be additional risk factors for the development of LMC.

Risk for leptomeningeal seeding after resection for brain metastases: implication of tumor location with mode of resection

Object

Surgical spillage has been one of the causative factors for the development of leptomeningeal seeding (LMS) after resection of brain metastases. In this paper, the authors' goal was to define the factors related to the development of LMS and to evaluate the difference according to tumor location.

Methods

The authors retrospectively analyzed 242 patients who had undergone resection for brain metastases. The factors investigated included tumor location with proximity to the CSF pathway (that is, contacting, involved with, or separated from the CSF pathway), the method of resection, and the use of the Cavitron Ultrasonic Surgical Aspirator (CUSA).

Results

A total of 39 patients (16%) developed LMS at a median of 6.0 months (range 1–42 months) after resection. The risk of developing LMS was significantly higher in patients whose tumors were resected piecemeal than in those whose tumors were removed en bloc, with a hazard ratio (HR) of 4.08 (p < 0.01). The incidence of LMS was significantly higher in patients in whom the CUSA was used, and the HR was 2.64 (p < 0.01). The proximity of tumor to the CSF pathway in the involved group conferred an increased risk of LMS compared with the separated group (HR 11.36, p < 0.01). The risk of piecemeal resection for LMS was significant only in involved lesions (p < 0.01), and the use of the CUSA in both contact and involved lesions increased the incidence of LMS (p < 0.01 and p < 0.03, respectively).

Conclusions

The authors suggest that piecemeal resection using the CUSA should be limited because of the risk of postsurgical LMS, especially when the tumor is in contact with the CSF pathway.

Using Self-Assembled Nanomaterials to Inhibit the Formation of Metastatic Cancer Stem Cell Colonies in Vitro

The isolation of cells with stem-like properties from prostate tumors suggests the presence of a cancer stem cell (CSC) population, which may account for the initiation, progression, and metastasis as well as drug resistance of the disease. We hypothesized that containing, or at least immobilizing, the CSCs in a nano-self-assembling material might help prevent prostate tumor progression or metastasis. CSCs were plated in three conditions: 1) placed in 1% concentration self-assembled peptide (SAP) preequilibrate with culture medium; 2) placed in 3% concentration SAP preequilibrate with culture medium; and 3) in nonadherent culture. All were grown for 14 days, after which the cells in both 1% and 3% concentrations were washed out of the SAP and grown for an additional 14 days. Here we report that CSCs from prostate cancer cell lines remained quiescent for more than 28 days when embedded in SAP. When the prostate CSCs were embedded in 1% and 3% SAP, most of the CSCs remained single cells 14 days after plating in a nonadherent plate; no prostaspheres could be detected 14 days after plating, suggesting that self-renewal was significantly suppressed. In the controls, prostate CSCs began to divide 1 day after plating in a nonadherent plate and prostaspheres were visible at day 10, indicating the active self-renewal property of the prostate CSCs. Our findings suggest that SAP can completely inhibit a prostate CSC from self-renewal while preserving its viability and CSC property. Therefore, SAP may be an effective nanomaterial for inhibiting cancer progression and metastasis to stop the progression during treatment and removal.

Comparative risk of leptomeningeal dissemination of cancer after surgery or stereotactic radiosurgery for a single supratentorial solid tumor metastasis

OBJECTIVE

To test the hypothesis that differential risks of developing leptomeningeal disease (LMD) exist in patients having a single supratentorial brain metastasis resected via a piecemeal or en bloc approach or treated with stereotactic radiosurgery (SRS).

METHODS

Between 1993 and 2006, 827 patients with a supratentorial brain metastasis underwent resection or SRS at The University of Texas M.D. Anderson Cancer Center. The primary outcome was the incidence of LMD.

RESULTS

Resection was performed piecemeal in 191 patients and en bloc in 351 patients; 285 patients received SRS. LMD occurred in 33 patients, 29 in the resection group and 4 in the SRS group. Risk of LMD was significantly higher with piecemeal tumor resection than with other procedures (SRS: hazard ratio [HR] for piecemeal, 5.8; 95% confidence interval [CI], 1.9-17.2; P = 0.002; en bloc, HR for piecemeal, 2.7; 95% CI, 1.3-5.6; P = 0.009). The difference between piecemeal and en bloc was particularly pronounced in patients with a melanoma primary (HR, 8.4; 95% CI, 1.8-39.2; P = 0.007). The risk of LMD was not significantly different between en bloc resection and SRS (HR for en bloc, 2.1; 95% CI, 0.7-6.4; P = 0.21). Similar results were obtained when comparing effects of SRS and both resection approaches after limiting the sample to patients with tumors in a specific volume range.

CONCLUSION

Piecemeal resection of a supratentorial brain metastasis carries a higher risk of LMD than en bloc resection or SRS. Further assessment of the role of the 2 surgical resection approaches and SRS in a controlled prospective setting with large numbers of patients is warranted.

Peritoneal carcinomatosis in urinary bladder cancer

PURPOSE

The objective of this study is to describe the computed tomography findings of peritoneal carcinomatosis of urinary bladder cancer.

MATERIAL AND METHOD

Patients with urinary bladder cancer were reviewed from patient database of our hospital, and 384 patients with urinary bladder cancer were identified. Computed tomography scans of 105 patients with urinary bladder cancer were retrospectively reviewed. Images were reviewed for presence of peritoneal implant, ascites, solid organ metastases, and retroperitoneal lymphadenopathy. Surgical history and follow-up courses of the patients were reviewed.

RESULTS

Computed tomography findings of peritoneal metastases were found in eight (7.6%) patients. Peritoneal involvement was diffuse in three patients and was in the form of implantation in five patients. In two patients, liver metastases were detected; additionally, one patient had accompanying pleural implants and one patient had adrenal gland metastases. Peritoneal involvement was detected in the preoperative stage in five patients.

CONCLUSION

Presence of peritoneal carcinomatosis in cancer patients is an indicator of poor prognosis. Detection of peritoneal involvement in urinary bladder cancer patients can alter treatment strategy and may prevent unnecessary aggressive surgical interventions.

Blocking alpha2 integrins on rat CC531s colon carcinoma cells prevents operation-induced augmentation of liver metastases outgrowth

Currently, an operation is the only curative option for patients with colorectal cancer. Unfortunately, many patients will develop liver metastases even after successful resection of the primary tumor. Removal of primary colorectal carcinoma may paradoxically increase the risk of metastases development, because accumulating evidence suggests that surgical trauma can stimulate tumor growth. In the present study, we investigated the effects of abdominal trauma on liver metastases development. Surgical trauma dramatically increased adhesion of tumor cells in the liver, leading to enhanced outgrowth of metastases. Endothelial stress was observed rapidly after an operation, suggesting that abdominal trauma resulted in impairment of blood vessel integrity. Tumor cells preferentially adhered to extracellular matrix (ECM). Furthermore, preincubation of tumor cells with anti-alpha2 integrin antibodies completely reverted operation-induced augmentation of CC531s adhesion and liver metastases outgrowth. As such, we postulate that blood vessel integrity in the liver is compromised after abdominal trauma, resulting in enhanced ECM exposure, which enables tumor cell adhesion and metastases outgrowth.

CONCLUSION

Perioperative treatments that either aim to reduce endothelial stress or block the interaction between tumor cells and ECM represent promising new therapeutic strategies for the prevention of liver metastases development after resection of the primary tumor.

Comparative risk of leptomeningeal disease after resection or stereotactic radiosurgery for solid tumor metastasis to the posterior fossa

Object

The authors tested the hypothesis that patients with metastatic posterior fossa lesions (MPFLs) treated with resection have a higher risk of leptomeningeal disease (LMD) than those with MPFLs treated with stereotactic radiosurgery (SRS).

Methods

Between 1993 and 2004, 379 patients with MPFLs were treated with resection or SRS at The University of Texas M. D. Anderson Cancer Center. The authors' primary study outcome was the incidence of LMD, as diagnosed with cerebrospinal fluid cytological analysis and/or neuroimaging.

Results

Resection was performed in 260 patients, whereas 119 patients underwent SRS. The median patient age was 56 years, 51% of patients were male, and 93% had a Karnofsky Performance Scale score $ 70. The most common primary cancers were those of the lung, breast, and kidney, as well as melanoma. Leptomeningeal dissemination of cancer occurred in 33 patients: 26 in the resection group and 7 in the SRS group (resection group: rate ratio [RR] 2.06, 95% confidence interval [CI] 0.89–4.75, p = 0.09). Piecemeal tumor resection (137 cases) was associated with a significantly higher risk of LMD than en bloc resection (123 cases; RR 3.4, 95% CI 1.43–8.12, p = 0.006) or SRS (RR 3.37, 95% CI 1.41–8.04, p = 0.006), and there was no significant difference in the risk for LMD between en bloc resection and SRS (en bloc resection: RR 0.98, 95% CI 0.34–2.81, p = 0.98). The multivariate RR and significance associated with piecemeal resection, however, were consistent, with a strong effect (RR 2.45, 95% CI 1.19–5.02, p = 0.02) and no indication of biases associated with tumor size, location, or cystic/necrotic appearance.

Conclusions

There is an increased risk of LMD after piecemeal resection of an MPFL. This increase, although clinically and statistically significant, is not as alarming as previously reported and is absent when en bloc removal is achieved. Further assessment of the role of resection in a controlled prospective setting is warranted.

Cytoreduction and intraperitoneal chemotherapy for the management of peritoneal carcinomatosis, sarcomatosis and mesothelioma

Despite new developments in multi-modality treatments, complete resection remains as an absolute requirement for cure of gastrointestinal cancer. We have reported benefits from combined treatment with complete cytoreduction and intraperitoneal chemotherapy. This has been achieved with low morbidity and mortality. Success in the surgical management of peritoneal surface malignancy depends on the surgeon's ability to complete complex cytoreductive procedures so that only microscopic residual disease remains. This paper describes the current strategy that the surgical oncologist should pursue in the treatment of patients with peritoneal carcinomatosis, sarcomatosis and mesothelioma. Technical details required for this surgery include patient position, incision and exposure, complete lysis of adhesion, electroevaporative dissection with irrigation and suction to preserve the translucent quality of tissues, peritonectomy procedures, proper positioning of tubes and drains for intraperitoneal chemotherapy, and reconstructive surgery. Understanding the treatment and mastery of surgical skills to manage the peritoneal surface spread of cancer has led to long-term survival of selected patients. Combination of this treatment strategy with proper patient selection has reduced the mortality and morbidity. The success of cytoreductive surgery and perioperative intraperitoneal chemotherapy depends on a long-term dedication to achieve the full potential of a curative outcome. Our unit has continued to achieve good results over two decades as improved results of treatment have evolved.

Principles of oncologic abdominal surgery

The principles of abdominal oncologic surgery parallel the general principles of all types of oncologic surgery with some variations peculiar to the abdomen. Due to the presence of multiple organ systems within the abdominal cavity, many types of cancer can develop. The surgeon must be prepared to perform several different abdominal procedures depending on the organ system involved and the extent of the cancer. The surgeon as oncologist must be aware of the tumor type, its expected behavior, and current treatment options. This article describes the principles of performing cancer surgery, including preparation for abdominal exploration, methods to facilitate tumor removal, and ways of avoiding tumor recurrence.

Role of cytokines and growth factors in promoting the local recurrence of breast cancer

The pathogenesis of local recurrence in breast cancer is not well understood. Breast-conserving surgery is particularly prone to local recurrence as it leaves behind breast tissue that may harbour occult cancer, and lends itself to enhanced intraoperative shedding of cancer cells due to narrower resection margins and transection of lymphatic channels. A review of clinical breast cancer studies as well as experimental research strongly suggests that these persisting cancerous cells are unlikely to develop into clinically evident disease if their environment remains unstimulated. However, an inordinately high local recurrence rate occurs at the surgical scar, and such recurrence must be triggered by the release of growth factors and cytokines into the healing wound. These factors can stimulate any available cancer cells which express the proper growth factor receptors. Perioperative strategies to neutralize this tumour cell-growth factor interaction should maximize local control.

Quantitative comparison of xenotransplantation of a human soft tissue sarcoma into the subcutaneous tissue of normal, postincision, and postincision plus indomethacin-treated nude mice

The purpose of this study was to test the hypotheses that (1) surgical wounding can enhance the xenotransplantability of a human soft tissue sarcoma (HSTS26T) into subcutaneous (s.c.) tissue of nude mice, and (2) Indomethacin may reduce the xenotransplantability of this human tumor in the surgical wounding animal model by suppressing angiogenesis. The experimental method was to employ the quantitative transplantation assays (TD50, the number of tumor cells that, on average, would be expected to induce a tumor in 50% of the recipients). After an incisional wound (1.0-1.2 cm long) was made on the right leg of each experimental mouse, tumor cells were inoculated into the surgical wound, or into the contralateral leg at 24 and 72 hr postincision, and in another group tumor cells were inoculated into the wound at 72 hr postincision, plus daily s.c. injection of indomethacin, 2 mg/kg body weight for 8 consecutive days in a separate experiment. Nonincisional mice received the same inoculation as the control groups. The TD50s of surgically wounded groups were 3.5-10.7 times lower than that of the control groups. Significantly lower TD50 values were found in groups of cells inoculated into the surgical wound at 72 hr postincision (P < 0.05 or P < 0.01) and into the contralateral leg at 24 hr postincision (P = 0.05). No significant difference was found between the TD50 values in mice that received cells inoculated at 72 hr postincision plus indomethacin treatment, and those with no wound controls. Our conclusion is that the surgical wound can enhance the xenotransplantability of HSTS26T in nude mice. Indomethacin can decrease this enhancing effect level similar to that in no-wound controls and may prevent tumor recurrence in a surgical wound.

Principles of surgical oncology

Surgical treatment of cancer has many advantages over other treatment modalities. The principles of defining the goal of surgery, surgical planning, surgical technique, surgical margins, and patient aftercare are reviewed. Special attention is devoted to tumor seeding and obtaining adequate margins. Incorporation of biologic behavior and stage of disease into the surgical plan are paramount to the successful implementation of surgery in cancer treatment.

Nativity, complications, and pathology are determinants of surgical results for gastric cancer

BACKGROUND

About half the patients involved in the current study were born outside of the United States. Epidemiologic and histologic features and survival estimates were compared with persons born in the United States. Results of gastrectomy with lymph node dissection were studied.

METHODS

Records of 187 patients with adenocarcinoma of the stomach were reviewed. Seventy-six with a curative gastrectomy were staged retrospectively. Univariate and multivariate analyses were done.

RESULTS

Seventy-six percent of histologically reviewed curative resections had the intestinal subtype with the same frequency in U.S.-born and foreign-born patients. Fewer patients with proximal third lesions were foreign born. Thirty-six percent had complications. The overall 5-year Kaplan-Meier survival estimate was 46%: 77% for patients with negative nodes and 33% for patients with positive nodes. N1 survival estimate was 44%; N2, 25%; N3(M1), 0%. All six patients with early gastric cancer are alive 50-147 months after surgery. Other stage I patients had estimated survival of 65%; Stage II, 52%; Stage III, 40%; and Stage IV, 0%. Multivariate analysis revealed four significant prognostic variables: nativity, histologic subgroup, presence of complications, and number of positive nodes.

CONCLUSIONS

Proximal gastric cancer was more common in U.S.-born persons. Gastric cancer may be more malignant in U.S.-born persons than in foreign-born persons because their survival was significantly poorer. Complications, a significant adverse factor, were more common in U.S. series. Pancreatectomy with gastrectomy is rarely indicated, because microscopic involvement is rare and complications frequent. The prognostic advantage of a regional lymphadenectomy remains unclear.