Mr McLeod, 66, died at Waipuna Hospice on October 1, 2012, from a severe reaction after a catheter inserted into his chest to administer chemotherapy drugs moved into his trachea.
The significance of the event was not appreciated by the radiologist nor the clinicians treating him.
Dr Bain said he agreed with Mr McLeod's family that there were "systematic inter-department failures" that resulted in a "cascade of missed opportunities" to prevent the tragic administration of highly toxic drugs going directly into his lungs on September 19, 2012.
On September 21, 2012, Mr McLeod had another coughing fit and coughed up a significant amount of blood and lost consciousness.
The cause of death was from acute pneumonia and chest infection against a background of rectal cancer treatment from 2011 and "significant and serious failings" in his health care.
Tauranga Hospital failed in five areas, including a failure to appreciate the severity of Mr McLeod's condition on September 19, and a lack of communication between the emergency radiology and oncology departments, the coroner said.
Dr Bain said the health board's deficiencies were "profound and alarming" and included significant deficiencies in the way the board communicated with the families.
The McLeod family asked the hospital and health board to make changes after Mr McLeod's death but the hospital failed to acknowledge their concerns nor change its protocols.
Dr Bain made a number of recommendations, including the need for unwell patients to be assessed medically before each course of chemotherapy, and phrases such as "position is unchanged" in patient reports should be avoided.
He recommended the changes should not only be implemented by Tauranga Hospital but applied nationwide, and inter-departmental gaps in communications should be addressed urgently.
Mr McLeod's son, Scott, told the Bay of Plenty Times Weekend, he, his brother, Peter, and mother Anne were "very pleased" with the inquiry outcomes.
"We are extremely grateful to Dr Bain as his findings and recommendations included a number of recommendations my dying father had called for."
Mr McLeod said the defensive nature of the DHB's response and the arrogance shown when they first raised their concerns was "quite disappointing".
"My mother was gutted. The DHB seemed to think the hospital had done nothing wrong. It's been a terrible burden to carry to ensure Curly's last wishes were fulfilled. It shouldn't have taken a family still grieving to force a coroner's inquiry to see changes made, and it wasn't a cheap process.
"But this was never about attributing blame. It has only ever been about making sure future patients get the best care possible and don't have to suffer what our family has gone through."
The coroner earlier said Mrs Strongman would still be alive "on the balance of probabilities" if there had been appropriate interventions, and reiterated that view in his report.
Mrs Strongman was admitted on June 17, 2010, with a cough, vomiting, dehydration, irregular pulse and a two-inch lump in her groin after referral by her GP.
Her death had earlier been the subject of a damning Health and Disability Commissioner report, which found the health board failed in its duty to provide an adequate level of care.
The Accident Compensation Corporation also held an inquiry and ACC accepted a claim after concluding there was an unreasonable failure to diagnose Mrs Strongman's condition and was caused by lack of appropriate treatment.
Inadequate records, inconsistent and flawed clinical handover processes by medical staff involved and a failure to diagnose an abdominal hernia with bowel obstruction resulted in breaches of the Code of Health and Disability Services Consumers' Rights, the report said.
Dr Bain said he endorsed the earlier recommendations made by the Health and Disability Commissioner and added four more, including a recommendation that an independent consultant be retained whenever there was a compliant laid with the Health and Disability Commissioner.
The Strongman family told the newspaper they wanted more time to consider Dr Bain's report before commenting.
In a written statement, Gail Bingham, the health board's governance and quality general manager, said "noted by Dr Bain the board frankly acknowledged its deficiencies in these cases and has demonstrated that significant remedial action has been taken in their aftermath to ensure they could not happen again".
