Colorectal Cancer Specialist in Guatemala
Colon and rectal cancer is treatable. With the right profile from diagnosis.
Not all colon cancers respond to the same medications. Some respond better to immunotherapy. Others shouldn't receive certain antibodies. Testing from the moment of diagnosis determines the right plan.
When should you consult Dr. Reynoso?
You were diagnosed with colon or rectal cancer and need a complete oncologic evaluation
Your diagnosis doesn't include MSI/MMR testing or RAS/BRAF mutation analysis
You have rectal bleeding, a change in bowel habits, or unexplained anemia
A mass was found on colonoscopy and you need guidance on the next step
Your current treatment isn't working and you're looking for options
You want a second opinion before starting chemotherapy
⚡ Consultations Monday, Tuesday, and Thursday | By appointment only
15%
of colorectal tumors are MSI-high — eligible for immunotherapy with far superior responses
40%
of metastatic colorectal cancers are RAS wild-type — eligible for anti-EGFR therapy
8+
years treating colorectal cancer at every stage in Guatemala
Q600
initial consultation with molecular review and treatment plan
MSI, RAS, BRAF. Three markers that change the treatment.
Colorectal cancer isn't a single disease. MSI/MMR status, RAS mutations (KRAS and NRAS), and BRAF V600E divide patients into groups with completely different treatments and prognoses. An MSI-high tumor responds extraordinarily well to immunotherapy. A RAS-mutated tumor doesn't respond to anti-EGFR antibodies.
Without knowing the molecular profile, it's impossible to select the best treatment for that specific tumor. A patient with RAS wild-type metastatic colorectal cancer treated with FOLFOX plus cetuximab has significantly better outcomes than with FOLFOX alone. That difference starts with molecular testing — and with an oncologist who knows how to use it.
“In metastatic colorectal cancer, the molecular profile isn't optional. RAS, BRAF, and MSI determine which agents are going to work and which aren't. Without that, treatment is generic when it could be specific.”—Dr. Giovanni Reynoso
Symptoms that shouldn't be ignored.
Colorectal cancer is often detected at advanced stages because early symptoms are subtle or attributed to benign conditions. Early diagnosis significantly improves the prognosis.
Rectal bleeding
Blood in the stool — red or black. Rectal bleeding in adults over 40 always requires a colonoscopy to rule out colorectal cancer.
Change in bowel habits
New, persistent diarrhea or constipation, a change in stool caliber, or a feeling of incomplete evacuation. A common symptom in rectal cancer.
Anemia with no obvious cause
Iron-deficiency anemia in an adult with no obvious explanation — occult bleeding in stool. May be the first sign of right-sided colon cancer with no obvious digestive symptoms.
Persistent abdominal pain
Abdominal pain or discomfort that doesn't improve and has no identified cause. May indicate partial obstruction or tumor extension.
Palpable abdominal mass
A palpable lump or mass in the abdomen — especially in the right iliac fossa. Common in advanced right-sided colon tumors.
Unexplained weight loss
Weight loss without a change in diet or physical activity. A common systemic symptom in advanced colorectal cancer.
Finding on colonoscopy
A large polyp, mass, or suspicious lesion on colonoscopy. Requires a biopsy and a complete oncologic evaluation with staging.
Elevated CEA
Elevated carcinoembryonic antigen on lab testing. In the right context, this may point toward colorectal cancer — or indicate relapse in patients with a prior diagnosis.
Do you identify with any of these?
A first one-hour consultation is enough to begin your workup and, if applicable, reach a clear diagnosis
The tumor progressed. There are more options than you were told.
Progression in metastatic colorectal cancer is one of the hardest moments for the patient and family. But it's not the end of the therapeutic road. Second- and third-line treatments have options with demonstrated benefit — and in MSI-high tumors without prior immunotherapy, the response can be extraordinary.
Progression on first-line treatment without immunotherapy
Patients with an MSI-high tumor treated only with conventional chemotherapy who never received pembrolizumab. In MSI-high cases, immunotherapy has response rates above 40% — far higher than any second-line chemotherapy. Identifying this profile in time completely changes the outlook.
Diagnosis without a complete molecular profile
Patients treated without RAS, BRAF, or MSI testing from diagnosis. Without that information, the oncologist couldn't choose the best agents from the start. Dr. Reynoso completes the profile on available tissue and redirects the strategy.
Initially unresectable metastatic disease
In some patients with liver or lung metastases, the right systemic treatment can convert an unresectable situation into a resectable one — opening the possibility of curative surgery. That evaluation requires active oncologic and surgical coordination.
“I've seen patients with MSI-high colorectal cancer treated with four lines of chemotherapy with no response. With pembrolizumab, the response was complete. The molecular profile isn't a detail — it's what determines whether the treatment is going to work.”—Dr. Giovanni Reynoso
How colorectal cancer is evaluated in consultation
A complete oncologic diagnosis of colorectal cancer requires histology, molecular profile, staging, and resectability assessment. The first consultation with Dr. Reynoso reviews what's already complete and what's missing to make the right decisions.
Complete case review
Detailed medical history, review of colonoscopy, imaging — CT of chest, abdomen, and pelvis, rectal MRI for rectal tumors — biopsy result, and prior treatments.
Complete molecular profile
MSI/MMR status, KRAS and NRAS mutations (exons 2, 3, and 4), BRAF V600E, and PD-L1 expression. If not yet performed, it's requested on available biopsy or surgical specimen tissue.
Staging
TNM classification to determine the stage — localized, locally advanced, or metastatic. In rectal cancer, MRI defines the circumferential margin and the need for neoadjuvant treatment.
Resectability assessment in metastatic disease
In liver or lung metastases, a multidisciplinary evaluation with surgery determines whether they're resectable — with curative intent — or whether management is palliative. Dr. Reynoso coordinates that evaluation.
Multidisciplinary coordination
In localized and locally advanced disease, the plan is designed in coordination with surgical oncology and radiotherapy. Dr. Reynoso defines the systemic component — chemotherapy, monoclonal antibodies, or immunotherapy.
Personalized treatment plan
With the molecular profile, stage, and complete multidisciplinary evaluation in hand, the protocol is designed — neoadjuvant, adjuvant, or palliative — with the right agents for that specific profile.
Why consult Dr. Reynoso for colon and rectal cancer?
Complete molecular profile from diagnosis
Dr. Reynoso doesn't design a colorectal cancer treatment protocol without knowing MSI, RAS, and BRAF status. Those three markers determine which agents are going to work and which aren't.
Immunotherapy available for MSI-high tumors
MSI-high colorectal tumors have extraordinary responses to pembrolizumab — superior to any available chemotherapy. Dr. Reynoso identifies these patients from diagnosis and treats them with the correct protocol.
Management of metastatic disease with curative intent when applicable
Not all metastatic colorectal disease is incurable. In resectable liver or lung metastases, prior systemic treatment can convert an unresectable situation into a resectable one. Dr. Reynoso evaluates this possibility in every case.
Real multidisciplinary coordination
Colorectal cancer requires surgery, radiotherapy, and medical oncology. Dr. Reynoso coordinates the systemic component with the surgical and radiotherapy team at Bonanova Health so the plan is coherent and complete.
Complete molecular profile from diagnosis
Dr. Reynoso doesn't design a colorectal cancer treatment protocol without knowing MSI, RAS, and BRAF status. Those three markers determine which agents are going to work and which aren't.
Immunotherapy available for MSI-high tumors
MSI-high colorectal tumors have extraordinary responses to pembrolizumab — superior to any available chemotherapy. Dr. Reynoso identifies these patients from diagnosis and treats them with the correct protocol.
Management of metastatic disease with curative intent when applicable
Not all metastatic colorectal disease is incurable. In resectable liver or lung metastases, prior systemic treatment can convert an unresectable situation into a resectable one. Dr. Reynoso evaluates this possibility in every case.
Real multidisciplinary coordination
Colorectal cancer requires surgery, radiotherapy, and medical oncology. Dr. Reynoso coordinates the systemic component with the surgical and radiotherapy team at Bonanova Health so the plan is coherent and complete.
Received a cancer diagnosis? The next step is a consultation.
First visit, second opinion, or oncologic follow-up — you deserve an oncologist who explains everything.
Medical Oncology in Guatemala City
Dr. Giovanni Reynoso - Oncólogo
Edificio Spazio, 15 avenida y 5 calle 5-50, Vista Hermosa III, Zona 15. Nivel 10, Oficina 10-01Bonanova Health, private hospital specializing in cancer in Zona 15
Office Hours
Monday to Tuesday from 4:00 PM to 6:00 PM Thursday from 3:00 PM to 5:00 PM
Emergency Care
Dr. Reynoso does not handle emergencies. For oncologic emergencies, go to the nearest hospital.
Coverage Areas
Guatemala City
- • Zona 15, Vista Hermosa I, II, and III
- • Zona 10, 14, 16
- • Zona 9, 13
- • Carretera a El Salvador
Metropolitan Area
- • Mixco
- • Villa Nueva
- • Santa Catarina Pinula
- • San Cristóbal
Departmental Coverage
- • All departments of Guatemala
- • Patients traveling from other parts of the country
- • Zacapa, Chiquimula, Izabal, San Marcos, Petén
International Coverage
- • El Salvador
- • Belize
- • Honduras
- • Costa Rica
Common questions, clear answers
Still have questions? Let’s talk directly on WhatsApp for personalized answers.